Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2018
Document And Entity Information [Abstract]
Document Type	S-1/A
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Trading Symbol	BIOC
Entity Registrant Name	BIOCEPT INC
Entity Central Index Key	0001044378
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true

Balance Sheets - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash	$ 8,956,200	$ 2,146,611	$ 4,609,332
Accounts receivable, net	1,476,454	1,193,426	128,969
Inventories, net	581,498	498,702	549,045
Prepaid expenses and other current assets	636,746	416,600	484,649
Total current assets	11,650,898	4,255,339	5,771,995
Fixed assets, net	2,900,994	3,123,567	1,806,331
Total assets	14,551,892	7,378,906	7,578,326
Current liabilities:
Accounts payable	1,792,541	1,269,953	960,486
Accrued liabilities	1,953,970	1,425,761	1,160,036
Supplier financings	120,802	61,226	75,691
Current portion of equipment financings	571,774	408,992	262,674
Current portion of credit facility, net		1,168,811	1,934,665
Total current liabilities	4,439,087	4,661,345	4,393,552
Interest payable		326,602	20,776
Non-current portion of equipment financings	1,016,352	1,150,063	778,643
Non-current portion of credit facility, net			1,123,001
Non-current portion of interest payable			227,177
Non-current portion of deferred rent	158,045	271,464	397,292
Total liabilities	5,613,484	6,082,872	6,919,665
Commitments and contingencies
Shareholders’ equity:
Preferred stock, $0.0001 par value, 5,000,000 authorized	1
Common stock, $0.0001 par value, 150,000,000 shares authorized	394	118	58
Additional paid-in capital	223,382,018	196,545,523	174,294,473
Accumulated deficit	(214,444,005)	(195,249,607)	(173,635,870)
Total shareholders’ equity	8,938,408	1,296,034	658,661
Total liabilities and shareholders’ equity	$ 14,551,892	7,378,906	$ 7,578,326
Scenario, Previously Reported [Member]
Current liabilities:
Accrued liabilities		1,752,363
Shareholders’ equity:
Common stock, $0.0001 par value, 150,000,000 shares authorized		3,518
Additional paid-in capital		$ 196,542,123

Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Preferred stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000	5,000,000
Preferred stock, shares issued	11,587	0	0
Preferred stock, shares outstanding	11,587	0	0
Common stock, par value	$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000	150,000,000
Common stock, shares issued	3,937,226	1,181,179	583,313
Common stock, shares outstanding	3,937,226	1,181,179	583,313

Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Net revenues	$ 761,591	$ 1,111,411	$ 2,390,772	$ 4,073,437	$ 5,068,663	$ 3,223,096
Costs and expenses:
Cost of revenues	2,481,916	2,487,054	7,616,473	6,985,213	9,345,122	6,920,111
Research and development expenses	1,089,746	856,698	3,179,612	2,455,947	3,364,747	2,713,367
General and administrative expenses	1,793,720	1,834,771	5,441,354	5,539,432	7,189,529	6,560,425
Sales and marketing expenses	1,404,192	1,675,852	4,473,908	4,701,030	6,343,971	5,054,230
Total costs and expenses	6,769,574	6,854,375	20,711,347	19,681,622	26,243,369	21,248,133
Loss from operations	(6,007,983)	(5,742,964)	(18,320,575)	(15,608,185)	(21,174,706)	(18,025,037)
Other income/ (expense):
Interest expense, net	(63,764)	(88,269)	(230,677)	(385,172)	(482,623)	(525,880)
Other income	23,963	12,804	(6,037)	51,216
Total other income/ (expense):	(39,801)	(75,465)	(236,714)	(333,956)	(431,407)	(372,232)
Other income					51,216	153,648
Loss before income taxes	(6,047,784)	(5,818,429)	(18,557,289)	(15,942,141)	(21,606,113)	(18,397,269)
Income tax expense		(2,877)	(739)	(5,023)	(7,624)	(2,053)
Net loss and comprehensive loss	(6,047,784)	(5,821,306)	(18,558,028)	(15,947,164)	$ (21,613,737)	$ (18,399,322)
Deemed dividend related to warrants down round provision	(636,370)		(636,370)
Net loss attributable to common shareholders	$ (6,684,154)	$ (5,821,306)	$ (19,194,398)	$ (15,947,164)
Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic	2,767,440	995,254	2,322,749	860,539	908,209	19,276
Diluted	2,759,614	995,254	2,320,111	860,539	908,209	19,276
Earnings Per Share [Abstract]
Basic	$ (2.42)	$ (6.00)	$ (8.26)	$ (18.53)	$ (23.80)	$ (57.63)
Diluted	$ (2.42)	$ (6.00)	$ (8.27)	$ (18.53)	$ (23.80)	$ (57.63)
Scenario, Previously Reported [Member]
Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic		986,865
Diluted		986,865
Earnings Per Share [Abstract]
Basic		$ (5.90)
Diluted		$ (5.90)

Statements of Shareholders' Equity - USD ($)	Total	May 2016 Offering [Member]	October 2016 Offering [Member]	March 2017 Registered Direct Offering [Member]	August 2017 Private Placement [Member]	December 2017 Registered Direct Offering [Member]	Common Stock [Member]	Common Stock [Member] May 2016 Offering [Member]	Common Stock [Member] October 2016 Offering [Member]	Common Stock [Member] March 2017 Registered Direct Offering [Member]	Common Stock [Member] August 2017 Private Placement [Member]	Common Stock [Member] December 2017 Registered Direct Offering [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] May 2016 Offering [Member]	Additional Paid-in Capital [Member] October 2016 Offering [Member]	Additional Paid-in Capital [Member] March 2017 Registered Direct Offering [Member]	Additional Paid-in Capital [Member] August 2017 Private Placement [Member]	Additional Paid-in Capital [Member] December 2017 Registered Direct Offering [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2015	$ 3,692,735						$ 21						$ 158,929,262						$ (155,236,548)
Beginning balance, shares at Dec. 31, 2015							218,556
Net loss	(4,875,198)
Ending balance at Mar. 31, 2016	(489,231)
Beginning balance at Dec. 31, 2015	3,692,735						$ 21						158,929,262						(155,236,548)
Beginning balance, shares at Dec. 31, 2015							218,556
Stock-based compensation expense	1,593,947												1,593,947
Shares issued for restricted stock units, shares							148
Shares and warrants issued, net of issuance costs	1,400,000	$ 4,333,283	$ 8,972,725					$ 5	$ 30					$ 4,333,278	$ 8,972,695
Aggregate shares sold under right offering								55,406	303,333
Shares issued pursuant to stock purchase agreement, net of issuance costs	465,293												465,293
Shares issued pursuant to stock purchase agreement, net of issuance costs, shares							5,772
Fractional shares issued upon one-for-three reverse stock split, shares							98
Net loss	(18,399,322)																		(18,399,322)
Ending balance at Dec. 31, 2016	658,661						$ 58						174,294,473						(173,635,870)
Ending balance, shares at Dec. 31, 2016							583,313
Beginning balance at Mar. 31, 2016	(489,231)
Net loss	(4,594,174)
Ending balance at Jun. 30, 2016	(419,402)
Net loss	(4,743,076)
Ending balance at Sep. 30, 2016	(4,556,158)
Net loss	(4,186,874)
Ending balance at Dec. 31, 2016	658,661						$ 58						174,294,473						(173,635,870)
Ending balance, shares at Dec. 31, 2016							583,313
Net loss	(4,432,707)
Ending balance at Mar. 31, 2017	10,418,069
Beginning balance at Dec. 31, 2016	658,661						$ 58						174,294,473						(173,635,870)
Beginning balance, shares at Dec. 31, 2016							583,313
Net loss	(15,947,164)
Ending balance at Sep. 30, 2017	4,026,079
Beginning balance at Dec. 31, 2016	658,661						$ 58						174,294,473						(173,635,870)
Beginning balance, shares at Dec. 31, 2016							583,313
Stock-based compensation expense	1,247,481												1,247,481
Shares issued for restricted stock units, shares							5,194
Shares issued upon exercise of common stock warrants	7,498,535						$ 23						7,498,512
Shares issued upon exercise of common stock warrants, shares							227,228
Shares and warrants issued, net of issuance costs				$ 8,559,959	$ 2,023,939	$ 2,921,196				$ 15	$ 45	$ 16				$ 8,559,944	$ 2,023,934	$ 2,921,180
Aggregate shares sold under right offering										144,000	48,889	164,167
Fractional shares issued upon one-for-thirty reverse stock split							$ 1						(1)
Fractional shares issued upon one-for-thirty reverse stock split, shares							8,388
Net loss	(21,613,737)																		(21,613,737)
Ending balance at Dec. 31, 2017	1,296,034						$ 118						196,545,523						(195,249,607)
Ending balance, shares at Dec. 31, 2017							1,181,179
Beginning balance at Mar. 31, 2017	10,418,069
Net loss	(5,693,151)
Ending balance at Jun. 30, 2017	7,342,257
Net loss	(5,821,306)
Ending balance at Sep. 30, 2017	4,026,079
Net loss	(5,666,573)
Ending balance at Dec. 31, 2017	1,296,034						$ 118						$ 196,545,523						$ (195,249,607)
Ending balance, shares at Dec. 31, 2017							1,181,179
Net loss	(18,558,028)
Ending balance at Sep. 30, 2018	$ 8,938,408

Statements of Cash Flows - USD ($)	9 Months Ended		12 Months Ended
Statements of Cash Flows - USD ($)	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Cash Flows from Operating Activities
Net loss	$ (18,558,028)	$ (15,947,164)	$ (21,613,737)	$ (18,399,322)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	580,366	394,708	575,717	322,029
Inventory reserve	(92,488)	(22,431)	(50,532)	(31,659)
Stock-based compensation	511,929	1,232,149	1,247,481	1,593,947
Non-cash interest expense related to credit facility and other financing activities	29,425	23,983	45,788	100,005
Gain on sale of fixed assets				(30,662)
Increase/(decrease) in cash resulting from changes in:
Accounts receivable, net	(283,028)	(1,004,403)	(1,064,457)	(94,769)
Inventory	9,692	(203,630)	100,875	(168,115)
Prepaid expenses and other current assets	277,720	431,355	518,863	494,734
Accounts payable	413,662	508,176	349,932	332,732
Accrued liabilities	497,119	671,407	236,927	165,543
Accrued interest	(241,034)	71,417	78,649	55,444
Deferred rent	(82,329)	(52,143)	(76,232)	(36,965)
Net cash used in operating activities	(16,936,994)	(13,896,576)	(19,650,726)	(15,697,058)
Cash Flows from Investing Activities:
Proceeds from sale of fixed assets				30,662
Purchases of fixed assets	(145,253)	(1,055,549)	(1,400,180)	(482,065)
Net cash used in investing activities	(145,253)	(1,055,549)	(1,400,180)	(451,403)
Cash Flows from Financing Activities:
Net proceeds from issuance of common stock and warrants	25,688,205	10,583,898	13,505,094	13,771,301
Proceeds from exercise of common stock warrants	0	7,498,535	7,498,535
Net proceeds from sale-leaseback transaction			150,848
Payments on equipment financings	(160,111)	(109,811)	(166,348)	(86,227)
Payments on supplier and other third-party financings	(438,290)	(314,270)	(465,279)	(510,123)
Payments on credit facility	(1,197,968)	(1,436,534)	(1,934,665)	(1,238,487)
Net cash provided by financing activities	23,891,836	16,221,818	18,588,185	11,936,464
Net increase (decrease) in Cash	6,809,589	1,269,693	(2,462,721)	(4,211,997)
Cash at Beginning of Period	2,146,611	4,609,332	4,609,332	8,821,329
Cash at End of Period	8,956,200	5,879,025	2,146,611	4,609,332
Cash paid during the period for:
Interest	379,587	285,260	358,471	358,632
Income taxes	$ 739	$ 5,023	$ 5,273	$ 2,053

Statements of Cash Flows (Parenthetical) - USD ($)	1 Months Ended	3 Months Ended	9 Months Ended		12 Months Ended
Statements of Cash Flows (Parenthetical) - USD ($)	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cancelled insurance premiums previously financed through third-parties, remaining principal outstanding balance			$ 31,000
Financed insurance premium through third party financing			488,000	$ 360,000	$ 451,000	$ 547,000
Fixed assets purchased under capital lease obligations			270,000	363,000	719,000	975,000
Purchases of fixed assets			$ 55,000	$ 205,000	31,000	58,000	$ 64,000
Preferred stock converted to shares of common stock	1,012,622	1,012,622	1,012,622
Deemed dividend related to warrants down round provision	$ 636,000	$ 636,370	$ 636,370
Cancellation of insurance premiums partial amount received						3,933
Fixed assets with an aggregate net book value					$ 34,000	270,000
Equipment financing obligations with remaining outstanding balances						$ 240,000
Common stock, par value	$ 0.0001	$ 0.0001	$ 0.0001		$ 0.0001	$ 0.0001
Warrants [Member]
Class of warrant or rights, first exercisable date					Jun. 05, 2018
Class of warrant or rights, expiration date					Dec. 05, 2022
Series A Preferred Stock [Member]
Shares converted		4,582

The Company, Business Activities and Basis of Presentation

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

The Company, Business Activities and Basis of Presentation

1. The Company, Business Activities and Basis of Presentation

The Company and Business Activities

The Company was founded in California in May 1997 and effected a reincorporation to Delaware in July 2013. The Company is an early stage molecular oncology diagnostics company that develops and commercializes proprietary circulating tumor cell, or CTC, and circulating tumor DNA, or ctDNA, assays utilizing a standard blood sample, or liquid biopsy. The Company’s current and planned assays are intended to provide information to aid healthcare providers to identify specific oncogenic alterations that may qualify a subset of cancer patients for targeted therapy at diagnosis, progression or for monitoring in order to identify specific resistance mechanisms. Sometimes traditional procedures, such as surgical tissue biopsies, result in tumor tissue that is insufficient and/or unable to provide the molecular subtype information necessary for clinical decisions. The Company’s assays, performed on blood, have the potential to provide more contemporaneous information on the characteristics of a patient’s disease when compared with tissue biopsy and radiographic imaging. Additionally, commencing in October 2017, the Company’s pathology partnership program, branded as Empower TC^TM, provides the unique ability for pathologists to participate in the interpretation of liquid biopsy results and is available to pathology practices and hospital systems throughout the United States. Further, sales to laboratory supply distributors of the Company’s proprietary blood collection tubes commenced during the three months ending June 30, 2018, which allow for the intact transport of liquid biopsy samples for research use only from regions around the world.

The Company operates a clinical laboratory that is CLIA-certified (under the Clinical Laboratory Improvement Amendment of 1988) and CAP-accredited (by the College of American Pathologists), and manufactures cell enrichment and extraction microfluidic channels, related equipment and certain reagents to perform the Company’s diagnostic assays in a facility located in San Diego, California. CLIA certification and accreditation are required before any clinical laboratory may perform testing on human specimens for the purpose of obtaining information for the diagnosis, prevention, treatment of disease, or assessment of health. The assays the Company offers are classified as laboratory developed tests under the CLIA regulations.

Basis of Presentation

The accompanying unaudited condensed financial statements and notes are prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, and on the basis that the Company will continue as a going concern (see Note 2). The accompanying unaudited condensed financial statements and notes do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern.

The unaudited condensed financial statements included in this Form 10-Q have been prepared in accordance with the U.S. Securities and Exchange Commission, or SEC, instructions for Quarterly Reports on Form 10-Q. Accordingly, the condensed financial statements are unaudited and do not contain all the information required by GAAP to be included in a full set of financial statements. The balance sheet at December 31, 2017 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by GAAP for a complete set of financial statements. The audited financial statements for the year ended December 31, 2017, filed with the U.S. Securities and Exchange Commission, or SEC, with our Annual Report on Form 10-K on March 28, 2018 include a summary of our significant accounting policies and should be read in conjunction with this Form 10-Q. In the opinion of management, all material adjustments necessary to present fairly the results of operations for such periods have been included in this Form 10-Q. All such adjustments are of a normal recurring nature. The results of operations for interim periods are not necessarily indicative of the results of operations for the entire year.

On July 6, 2018, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s Certificate of Amendment of Certificate of Incorporation to effect a one-for-thirty reverse stock split of the Company’s outstanding common stock. As such, all references to share and per share amounts in these unaudited condensed financial statements and accompanying notes have been retroactively restated to reflect the one-for-thirty reverse stock split, except for the authorized number of shares of the Company’s common stock of 150,000,000 shares, which was not affected by the one-for-thirty reverse stock split.

Certain prior period balances have been reclassified to conform to the current period presentation.

Revenue Recognition and Accounts Receivable

The Company's commercial revenues are generated from diagnostic services provided to patient’s physicians and billed to third-party insurance payers such as managed care organizations, Medicare and Medicaid and patients for any deductibles, coinsurance or copayments that may be due. Through December 31, 2017, the Company recognized revenue in accordance with the provisions of Accounting Standards Codification, or ASC, 954-605, Health Care Entities—Revenue Recognition, which required that four basic criteria must be met prior to recognition of revenue: (1) persuasive evidence of an arrangement existed; (2) delivery had occurred and title and the risks and rewards of ownership had been transferred to the client or services had been rendered; (3) the price was fixed or determinable; and (4) collectability was reasonably assured. Commencing on March 31, 2017, the Company recognized commercial revenue related to billings for assays delivered and billed to Medicare and other third-party payers on an accrual basis when amounts that will ultimately be realized can be estimated upon delivery, whereby prior to March 31, 2017, the Company recognized revenues for its commercial diagnostic services on a cash basis as collected because the amounts ultimately expected to be received could not be estimated upon delivery due to insufficient collection history experience. Commencing on January 1, 2018, the Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers, or ASC 606, which requires that an entity recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. The Company adopted the provisions of ASC 606 using the modified retrospective application method applied to all contracts, which did not impact amounts previously reported by the Company, nor did it require a cumulative effect adjustment upon adoption, as the Company’s method of recognizing revenue under ASC 606 was analogous to the method utilized immediately prior to adoption. Accordingly, there is no need for the Company to disclose the amount by which each financial statement line item was affected as a result of applying the new standard and an explanation of significant changes.

Contracts

For its commercial revenues, while the Company markets directly to physicians, its customer is the patient. Patients do not enter into direct agreements with the Company that commit either them to pay any portion of the cost of the tests if they have not met their annual deductible limit under their insurance policy, if any, or if their insurance otherwise declines to reimburse the Company. Accordingly, the Company establishes a contract with a commercial patient in accordance with other customary business practices, as follows:


	•		Approval of a contract is established via the order and accession, which are submitted by the patient’s physician.
	•		The Company is obligated to perform its diagnostic services upon receipt of a sample from a physician, and the patient and/or applicable payer are obligated to reimburse the Company for services rendered based on the patient’s insurance benefits.


	•		Payment terms are a function of a patient’s existing insurance benefits, including the impact of coverage decisions with CMS and applicable reimbursement contracts established between the Company and payers, unless the patient is a self-pay patient, whereby the Company bills the patient directly after the services are provided.
	•		Once the Company delivers a patient’s assay result to the ordering physician, the contract with a patient has commercial substance, as the Company is legally able to collect payment and bill an insurer and/or patient, regardless of payer contract status or patient insurance benefit status.


	•		Consideration associated with commercial revenues is considered variable and constrained until fully adjudicated, with net revenues recorded to the extent that it is probable that a significant reversal will not occur.

The Company’s development services revenues are supported by contractual agreements and generated from assay development services provided to entities, as well as certain other diagnostic services provided to physicians, and revenues are recognized upon delivery of the performance obligations in the contract.

Performance Obligations

A performance obligation is a promise in a contract to transfer a distinct good or service, or a bundle of goods or services, to the customer. For its commercial and development services revenues, the Company’s contracts have a single performance obligation, which is satisfied upon rendering of services, which culminates in the delivery of a patient’s assay result(s) to the ordering physician or entity. The duration of time between accession receipt and delivery of a valid assay result to the ordering physician or entity is typically less than two weeks. Accordingly, the Company elected the practical expedient and therefore, does not disclose the value of unsatisfied performance obligations.

Transaction Price

The transaction price is the amount of consideration that the Company expects to collect in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties, such as sales taxes. The consideration expected from a contract with a customer may include fixed amounts, variable amounts, or both. The Company’s gross commercial revenues billed, and corresponding gross accounts receivable, are subject to estimated deductions for such allowances and reserves to arrive at reported net revenues, which relate to differences between amounts billed and corresponding amounts estimated to be subsequently collected and is deemed to be variable although the variability is not explicitly stated in any contract. Rather, the implied variability is due to several factors, such as the payment history or lack thereof for third-party payers, reimbursement rate changes for contracted and non-contracted payers, any patient co-payments, deductibles or compliance incentives, the existence of secondary payers and claim denials. The Company estimates the amount of variable consideration using the most likely amount approach to estimating variable consideration for third-party payers, including direct patient bills, whereby the estimated reimbursement for services are established by payment histories on CPT codes for each payer, or similar payer types. When no payment history is available, the value of the account is estimated at Medicare rates, with additional other payer-specific reserves taken as appropriate. Collection periods for billings on commercial revenues range from less than 30 days to several months, depending on the contracted or non-contracted nature of the payer, among other variables. The estimates of amounts that will ultimately be realized from commercial diagnostic services for non-contracted payers require significant judgment by management.

The Company limits the amount of variable consideration included in the transaction price to the unconstrained portion of such consideration. Revenue is recognized up to the amount of variable consideration that is not subject to a significant reversal until additional information is obtained or the uncertainty associated with the additional payments or refunds is subsequently resolved. Differences between original estimates and subsequent revisions, including final settlements, represent changes in the estimate of variable consideration and are included in the period in which such revisions are made. The Company monitors its estimates of transaction price to depict conditions that exist at each reporting date. If the Company subsequently determines that it will collect more consideration than it originally estimated for a contract with a customer, it will account for the change as an increase in the estimate of the transaction price in the period identified as an increase to revenue. Similarly, if the Company subsequently determines that the amount it expects to collect from a customer is less than it originally estimated, it will generally account for the change as a decrease in the estimate of the transaction price as a decrease to revenue, provided that such downward adjustment does not result in a significant reversal of cumulative revenue recognized. Revenue recognized from changes in transaction prices was not significant during the three and nine months ended September 30, 2018.

Allocate Transaction Price

For the Company’s commercial revenues, the entire transaction price is allocated to the single performance obligation contained in a contract with a customer. For the Company’s development services revenues, the contracted transaction price is allocated to each single performance obligation contained in a contract with a customer as performed.

Point-in-time Recognition

The Company’s single performance obligation is satisfied at a point in time, and that point in time is defined as the date a patient’s successful assay result is delivered to the patient’s ordering physician or entity. The Company considers this date to be the time at which the patient obtains control of the promised diagnostic assay service.

Contract Balances

The timing of revenue recognition, billings and cash collections results in accounts receivable recorded in the Company’s condensed balance sheets. Generally, billing occurs subsequent to delivery of a patient’s test result to the ordering physician or entity, resulting in an account receivable.

Practical Expedients

The Company does not adjust the transaction price for the effects of a significant financing component, as at contract inception, the Company expects the collection cycle to be one year or less.

The Company expenses sales commissions when incurred because the amortization period is one year or less, which are recorded within sales and marketing expenses.

The Company incurs certain other costs that are incurred regardless of whether a contract is obtained. Such costs are primarily related to legal services and patient communications. These costs are expensed as incurred and recorded within general and administrative expenses.

Disaggregation of Revenue and Concentration of Risk

The composition of the Company’s net revenues recognized during the three and nine months ended September 30, 2017 and 2018, disaggregated by source and nature, are as follows:

	For the three months ended September 30,				For the nine months ended September 30,
	2017		2018		2017		2018
Net revenues from contracted payers*	$	422,136	$	325,097	$	1,655,287	$	1,019,857
Net revenues from non-contracted payers		621,881		373,018		2,206,414		1,211,309
Development services revenues		67,394		63,476		211,736		159,606
Total net revenues	$	1,111,411	$	761,591	$	4,073,437	$	2,390,772

*Includes Medicare and Medicare Advantage, as reimbursement amounts are fixed and miscellaneous income from CEE-Sure blood collection tubes.

	For the three months ended September 30,				For the nine months ended September 30,
	2017		2018		2017		2018
Net commercial revenues recognized upon delivery	$	941,783	$	698,115	$	2,703,424	$	2,231,166
Development services revenues recognized upon delivery		67,394		63,476		211,736		159,606
Commercial revenues recognized upon cash collection		102,234		—		1,158,277		—
Total net revenues	$	1,111,411	$	761,591	$	4,073,437	$	2,390,772

The amount of nonrecurring net revenue recorded during the three and nine months ended September 30, 2017, had the Company commenced recognizing revenue for commercial diagnostic services upon delivery on or prior to December 31, 2016 instead of on March 31, 2017, was $102,000 and $839,000, respectively, and the corresponding decrease in net loss per common share was $0.10 and $0.97, respectively. The incremental net revenue and decrease in loss from operations as a result of recognizing revenue on an accrual basis commencing on March 31, 2017, or the total amount of net revenue recorded in excess of the amount of commercial cash collections, was $125,000 and $1,158,000 during the three and nine months ended September 30, 2017, respectively, and the corresponding decrease in net loss per common share was $0.13 and $1.35, respectively. For the nine months ended September 30, 2018 all revenues were recognized on an accrual basis.

Concentrations of credit risk with respect to revenues are primarily limited to geographies to which the Company provides a significant volume of its services, and to specific third-party payers of the Company’s services such as Medicare, insurance companies, and other third-party payers. The Company’s client base consists of many geographically dispersed clients diversified across various customer types.

The Company's third-party payers that represent more than 10% of total net revenues in any period presented, as well as their related net revenue amount as a percentage of total net revenues, during the three and nine months ended September 30, 2017 and 2018 were as follows:

	For the three months ended September 30,						For the nine months ended September 30,
	2017			2018			2017			2018
Medicare and Medicare Advantage		45	%		40	%		41	%		39	%
Blue Cross Blue Shield		16	%		9	%		17	%		14	%
United Healthcare		14	%		6	%		12	%		15	%

The Company's third-party payers that represent more than 10% of total net accounts receivable, and their related net accounts receivable balance as a percentage of total net accounts receivable, at December 31, 2017 and September 30, 2018 were as follows:

	December 31, 2017			September 30, 2018
Blue Cross Blue Shield		27	%		22	%
Medicare and Medicare Advantage		21	%		18	%
United Healthcare		15	%		11	%

Recent Accounting Pronouncements

In May 2014, and as subsequently updated and amended from time to time, the Financial Accounting Standards Board, or FASB, issued authoritative guidance that requires entities to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. This guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period, and may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. The Company adopted the new standard for the fiscal year beginning January 1, 2018 using the modified retrospective application method, which did not have a material impact on its financial statements or disclosures.

In January 2016, the FASB issued authoritative guidance requiring, among other things, that certain equity investments be measured at fair value with changes in fair value recognized in net income, that financial assets and financial liabilities be presented separately by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements, that the prior requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet be eliminated, and that a reporting organization is to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. This guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. The Company adopted this guidance for the fiscal year beginning on January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In February 2016, the FASB issued authoritative guidance requiring, among other things, that entities recognize the assets and liabilities arising from leases on the balance sheet under revised criteria, while the classification criteria for distinguishing between finance leases and operating leases are substantially similar to the classification criteria in the previous leases guidance. In transition, lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company anticipates that the adoption of this guidance will materially affect its statement of financial position and will require changes to its processes. The Company expects to adopt this guidance for the reporting period beginning on January 1, 2019 and has not yet made a decision on the method of adoption with respect to the optional practical expedients.

In August 2016, the FASB issued authoritative guidance clarifying the classification of certain cash receipts and cash payments in the statement of cash flows. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, on a retrospective transition method to each period presented. The Company adopted this guidance for the reporting period beginning January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In January 2017, the FASB issued authoritative guidance clarifying the definition of a business when evaluating transactions involving acquisitions or disposals of assets or businesses. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company adopted this guidance for the reporting period beginning January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In July 2017, the FASB issued authoritative guidance changing the classification analysis of certain equity-linked financial instruments (or embedded features) with down round features, whereby a down round feature no longer precludes equity classification when assessing whether the instrument is indexed to an entity’s own stock, and also clarifying existing disclosure requirements for equity-classified instruments. This guidance is effective for fiscal years beginning after December 15, 2019, and interim periods within fiscal years beginning after December 15, 2020. Early adoption is permitted. The Company early adopted this guidance for the fiscal year beginning on January 1, 2018, which did not have a material impact on its financial statements or disclosures upon adoption, but did result in equity classification for the warrants issued on January 30, 2018, whereby liability classification may have occurred in the absence of the adoption of this guidance due to the existence of a down round feature associated with the exercise price of the warrants, which would have resulted in material impacts to the Company’s financial statements and disclosures.

In August 2017, the FASB issued authoritative guidance that expands and refines hedge accounting for both nonfinancial and financial risk components and align the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. This guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early application is permitted. The Company currently intends to adopt this guidance for the fiscal year beginning on January 1, 2019 and does not anticipate that the adoption of this guidance will have a material impact on its financial statements or disclosures because the Company does not currently hold any financial instruments accounted for as a hedging activity.

In February 2018, the FASB issued authoritative guidance allowing a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from a tax bill, “H.R.1, An Act to Provide for Reconciliation Pursuant to Titles II and V of the Concurrent Resolution on the Budget for Fiscal Year 2018,” or the Tax Cuts and Jobs Act, enacted on December 22, 2017. These amendments eliminate the stranded tax effects resulting from the Tax Cuts and Jobs Act. However, because these amendments only relate to the reclassification of the income tax effects of the Tax Cuts and Jobs Act, the underlying guidance that requires that the effect of a change in tax laws or rates be included in income from continuing operations is not affected. This guidance also requires certain disclosures about stranded tax effects. This guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The Company currently intends to adopt this guidance for the fiscal year beginning on January 1, 2019 and does not anticipate that the adoption of this guidance will have a material impact on its financial statements or disclosures because the Company does not currently maintain any stranded tax effects in accumulated other comprehensive income.

In February 2018, the FASB issued authoritative guidance concerning certain fair value option liabilities, equity securities without a readily determinable fair value, and certain equity investments. This guidance is effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years beginning after June 15, 2018. Public entities with fiscal years beginning between December 15, 2017 and June 15, 2018 are not required to adopt these amendments until the interim period beginning after June 15, 2018. The Company adopted this guidance for the interim period beginning on July 1, 2018, which did not have a material impact on its financial statements or disclosures because the Company did not hold any fair value option liabilities, equity securities without a readily determinable fair value, or equity investments.

Liquidity and Going Concern Uncertainty	9 Months Ended	12 Months Ended
Liquidity and Going Concern Uncertainty	Sep. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Liquidity and Going Concern Uncertainty	2. Liquidity and Going Concern Uncertainty As of September 30, 2018, cash totaled $9.0 million and the Company had an accumulated deficit of $214.4 million. For the nine months ended September 30, 2018, the Company incurred a net loss of $18.6 million. At September 30, 2018, the Company had aggregate net interest-bearing indebtedness of $1.7 million, of which $693,000 was due within one year whereas at September 30, 2017, the Company had aggregate net interest-bearing indebtedness of $3.3 million, of which $2.4 million was due within one year in the absence of subjective acceleration of amounts due under a credit facility entered into in April 2014 with Oxford Finance LLC, or the April 2014 Credit Facility. Additionally, in February 2016, the Company signed a firm, non-cancelable, and unconditional commitment in an aggregate amount of $1,062,500 with a vendor to purchase certain inventory items, payable in minimum quarterly amounts of $62,500 through May 2020, under which $404,000 remained outstanding at September 30, 2018 (see Note 11). These factors raise substantial doubt about the Company’s ability to continue as a going concern for the one-year period following the date that these financial statements were issued. The accompanying financial statements and notes have been prepared assuming that the Company will continue as a going concern. The accompanying financial statements and notes do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern. While the Company is currently in the commercialization stage of operations, the Company has not yet achieved profitability and anticipates that it will continue to incur net losses for the foreseeable future. Historically, the Company’s principal sources of cash have included proceeds from the issuance of common and preferred stock, proceeds from the exercise of warrants to purchase common stock, proceeds from the issuance of debt, and revenues from laboratory services. The Company’s principal uses of cash have included cash used in operations, payments relating to purchases of property and equipment and repayments of borrowings. The Company expects that the principal uses of cash in the future will be for continuing operations, hiring of sales and marketing personnel and increased sales and marketing activities, funding of research and development, capital expenditures, and general working capital requirements. The Company expects that, as revenues grow, sales and marketing and research and development expenses will continue to grow, albeit at a slower rate and, as a result, the Company will need to generate significant growth in net revenues to achieve and sustain income from operations. On September 20, 2018, the Company completed an offering of 642,438 shares of the Company’s common stock and pre-funded warrants to purchase up to an aggregate of 120,000 shares of its common stock. The shares were sold at a purchase price of $3.285 per share and the pre-funded warrants were sold at a purchase price of $3.275 per pre-funded warrant which represents the per share purchase price for the shares less the $0.01 per share exercise price for each such pre-funded warrant. The net proceeds to the Company from the offering were approximately $2.2 million, after deducting expenses related to the offering including dealer-manager fees and expenses, and excluding any proceeds received upon exercise of any warrants. In addition, in a concurrent private placement, the Company issued to purchasers a warrant to purchase one share of the Company’s common stock for each share and pre-funded warrant purchased for cash in the offering. All warrants issued in this offering have an exercise price of $3.16 per share, are exercisable upon the six-month anniversary of issuance and expire five years from such date. On August 13, 2018, the Company completed a rights offering pursuant to an effective registration statement. Pursuant to the rights offering, the Company sold an aggregate of 11,587 units consisting of an aggregate of 11,587 shares of Series A Preferred Stock and 2,549,140 warrants, with each warrant exercisable for one share of its common stock at an exercise price of $4.53 per share, resulting in net proceeds to the Company of approximately $10.2 million, after deducting expenses relating to the rights offering, including dealer-manager fees and expenses, and excluding any proceeds received upon exercise of any warrants. In May 2018, the SEC declared effective a shelf registration statement filed by the Company, which expires in May 2021. The shelf registration statement allows the Company to issue any combination of its common stock, preferred stock, debt securities and warrants from time to time for an aggregate initial offering price of up to $50 million, subject to certain limitations for so long as its public float is less than $75 million. On January 30, 2018, the Company received net cash proceeds of approximately $13.3 million from the closing of a follow-on public offering of 1,095,153 shares of its common stock and warrants to purchase up to an aggregate of 1,095,153 shares of its common stock at a combined offering price of $13.50 per unit. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering, with approximately $16.4 million in gross warrant proceeds remaining outstanding and available to be exercised at $15.00 per share, which is subject to down round adjustment, until their expiration in January 2023. Pursuant to a common stock and warrant purchase agreement dated August 9, 2017 between the Company and Ally Bridge LB Healthcare Master Fund Limited, or Ally Bridge, the Company received net cash proceeds of approximately $2.0 million from the sale of its common stock and warrants. Subsequent to the closing of this offering, no additional cash proceeds had been received from the exercise of warrants sold in this offering, with approximately $2.2 million in gross warrant proceeds remaining outstanding and available to be exercised at $45.00 per share until their expiration in August 2022. Management’s Plan to Continue as a Going Concern In order to continue as a going concern, the Company will need, among other things, additional capital resources. Until the Company can generate significant cash from operations, including assay revenues, management’s plans to obtain such resources for the Company include proceeds from offerings of the Company’s equity securities or debt, cash received from the exercise of outstanding common stock warrants, or transactions involving product development, technology licensing or collaboration. Management can provide no assurances that any sources of a sufficient amount of financing will be available to the Company on favorable terms, if at all.	2. Liquidity and Going Concern Uncertainty As of December 31, 2017, cash totaled $2.1 million and the Company had an accumulated deficit of $195.2 million. For the years ended December 31, 2016 and 2017, the Company incurred net losses of $18.4 million and $21.6 million, respectively. At December 31, 2017, the Company had aggregate net interest-bearing indebtedness of approximately $3.1 million, of which approximately $2.0 million was due within one year, in addition to approximately $2.7 million of other non-interest bearing current liabilities. Additionally, in February 2016, the Company signed a firm, non-cancelable, and unconditional commitment in an aggregate amount of $1,062,500 with a vendor to purchase certain inventory items, payable in minimum quarterly amounts of $62,500 through May 2020, under which approximately $611,000 remained outstanding at December 31, 2017 (see Note 16). These factors raise substantial doubt about the Company’s ability to continue as a going concern for the one-year period following the date that these financial statements were issued. The accompanying financial statements and notes have been prepared assuming that the Company will continue as a going concern. The accompanying financial statements and notes do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern. While the Company is currently in the commercialization stage of operations, the Company has not yet achieved profitability and anticipates that it will continue to incur net losses for the foreseeable future. Historically, the Company’s principal sources of cash have included proceeds from the issuance of common and preferred stock, proceeds from the exercise of warrants to purchase common stock, proceeds from the issuance of debt, and revenues from laboratory services. The Company’s principal uses of cash have included cash used in operations, payments relating to purchases of property and equipment and repayments of borrowings. The Company expects that the principal uses of cash in the future will be for continuing operations, hiring of sales and marketing personnel and increased sales and marketing activities, funding of research and development, capital expenditures, and general working capital requirements. The Company expects that, as revenues grow, sales and marketing and research and development expenses will continue to grow, albeit at a slower rate and, as a result, the Company will need to generate significant growth in net revenues to achieve and sustain income from operations. In May 2015, the SEC declared effective a shelf registration statement filed by the Company, which expires in May 2018. The shelf registration statement allows the Company to issue any combination of its common stock, preferred stock, debt securities and warrants from time to time for an aggregate initial offering price of up to $50 million, subject to certain limitations for so long as its public float is less than $75 million. Pursuant to an exclusive placement agent agreement dated April 25, 2016 between the Company and H.C. Wainwright & Co., LLC, or Wainwright, and a securities purchase agreement dated April 29, 2016 between the Company and the purchasers signatory thereto, the Company received approximately $4.3 million of net cash proceeds upon the sale of its common stock and warrants to purchase its common stock. Subsequent to the closing of this offering on May 4, 2016, no warrants sold in this offering have been exercised, with approximately $4.5 million in gross warrant proceeds remaining outstanding and available to be exercised at $117.00 per share until their expiration in May 2021. Pursuant to an exclusive placement agent agreement dated March 28, 2017 between the Company and Roth Capital Partners, LLC as lead placement agent, and WestPark Capital and Chardan Capital as co-placement agents, a securities purchase agreement for an offering of 144,000 shares of the Company’s common stock was effected under this registration statement at a per share price of $64.50. In a concurrent private placement, the Company sold unregistered warrants to purchase up to an aggregate of 72,000 shares of its common stock that closed concurrently with the offering common stock sold pursuant to this shelf registration statement, of which none have been subsequently exercised. All warrants sold in this offering have a per share exercise price of 75.00 and expire on October 1, 2022. The closing of the sale of these securities to the purchasers occurred on March 31, 2017, when the Company received approximately $8.6 million of net cash proceeds. Pursuant to an exclusive placement agent agreement dated December 5, 2017 between the Company and Dawson James Securities, Inc. as lead placement agent, and WestPark Capital as co-placement agent, a securities purchase agreement for a registered direct offering of 164,166 shares of the Company’s common stock was effected under this registration statement at a per share price of $20.40. The placement agent was issued a warrant to purchase 8,208 shares of common stock at an exercise price of $25.50 per share, which is first exercisable on June 5, 2018 and expires on December 5, 2022. The closing of the sale of these securities occurred on December 8, 2017, when the Company received approximately $2.9 million of net cash proceeds. The specific terms of additional future offerings, if any, under this shelf registration statement would be established at the time of such offerings. On October 19, 2016, the Company received net cash proceeds of approximately $9.0 million as a result of the closing of a follow-on public offering. Subsequent to the closing of this offering on October 19, 2016, the offering’s underwriters exercised their overallotment option to purchase 20,904 option warrants for total proceeds of $564. Subsequent to the closing of this offering, approximately $7.5 million of additional cash proceeds had been received from the exercise of warrants sold in this offering, with approximately $3.2 million in gross warrant proceeds remaining outstanding and available to be exercised at $33.00 per share until their expiration in October 2021. Pursuant to a common stock and warrant purchase agreement dated August 9, 2017, the Company received net cash proceeds of approximately $2.0 million as a result of the sale of its common stock and warrants. Subsequent to the closing of this offering, no additional cash proceeds had been received from the exercise of warrants sold in this offering, with approximately $2.2 million in gross warrant proceeds remaining outstanding and available to be exercised at $45.00 per share until their expiration in August 2022. On January 30, 2018, the Company received net cash proceeds of approximately $13.3 million as a result of the closing of a follow-on public offering. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering, with approximately $16.4 million in gross warrant proceeds remaining outstanding and available to be exercised at $15.00 per share, subject to down round adjustment, until their expiration in January 2023. Management’s Plan to Continue as a Going Concern In order to continue as a going concern, the Company will need, among other things, additional capital resources. Until the Company can generate significant cash from operations, including assay revenues, management’s plans to obtain such resources for the Company include proceeds from offerings of the Company’s equity securities or debt, or transactions involving product development, technology licensing or collaboration. Management can provide no assurances that any sources of a sufficient amount of financing will be available to the Company on favorable terms, if at all.

Sales of Equity Securities	9 Months Ended	12 Months Ended
Sales of Equity Securities	Sep. 30, 2018	Dec. 31, 2017
Equity [Abstract]
Sales of Equity Securities	3. Sales of Equity Securities In May 2015, the SEC declared effective a shelf registration statement filed by the Company, which expired on May 21, 2018. The shelf registration statement allowed the Company to issue any combination of its common stock, preferred stock, debt securities and warrants from time to time for an aggregate initial offering price of up to $50 million, subject to certain limitations for so long as the Company’s public float was less than $75 million. Pursuant to an exclusive placement agent agreement dated March 28, 2017 between the Company and Roth Capital Partners, LLC as lead placement agent, and WestPark Capital and Chardan Capital as co-placement agents, a securities purchase agreement for an offering of 144,000 shares of the Company’s common stock was effected under this registration statement at a per share price of $64.50, which closed on March 31, 2017. In a concurrent private placement, the Company sold unregistered warrants to purchase up to an aggregate of 72,000 shares of the Company’s common stock that closed concurrently with the March 2017 offering of common stock sold pursuant the shelf registration statement, of which none have been subsequently exercised. The warrants sold in this offering have a per share exercise price of $75.00, expire on October 1, 2022, and had an aggregate estimated fair value of approximately $2.8 million. At the closing of these sales on March 31, 2017, the Company received approximately $8.6 million of net cash proceeds after deducting $0.7 million of costs directly associated with the offering that were recorded as an offset to additional paid-in capital under applicable accounting guidance. Pursuant to an exclusive placement agent agreement dated December 5, 2017 between the Company and Dawson James Securities, Inc. as lead placement agent, and WestPark Capital as co-placement agent, a securities purchase agreement for a registered direct offering of 164,166 shares of the Company’s common stock was effected under this registration statement at a per share price of $20.40. The placement agent was issued a warrant to purchase 8,208 shares of common stock at an exercise price of $25.50 per share with an estimated grant date fair value of approximately $0.1 million, which expires on December 5, 2022. The closing of the sale of these securities occurred on December 8, 2017, when the Company received approximately $2.9 million of net cash proceeds after deducting $0.4 million of costs directly associated with the offering that were recorded as an offset to additional paid-in capital under applicable accounting guidance. Pursuant to an exclusive placement agent agreement dated March 28, 2017 between the Company and Roth Capital Partners, LLC as lead placement agent, and WestPark Capital and Chardan Capital as co-placement agents, a securities purchase agreement for a second offering of 144,000 shares of the Company’s common stock was effected under this registration statement at per share price of $64.50, which closed on March 31, 2017. In a concurrent private placement, the Company sold unregistered warrants to purchase up to an aggregate of 72,000 shares of the Company’s common stock that closed concurrently with the March 2017 offering of common stock sold pursuant the shelf registration statement. All warrants sold in this offering have a per share exercise price of $75.00, are exercisable beginning on the six-month anniversary of the date of issuance and expire five years from the date first exercisable. The estimated grant date fair value of these warrants of approximately $2.8 million was recorded as an offset to additional paid-in capital upon the closing of this offering (see Note 4). At the closing of these sales on March 31, 2017, the Company received, after deducting $0.7 million of costs directly associated with the offering that were recorded as an offset to additional paid-in capital under applicable accounting guidance, approximately $8.6 million of net cash proceeds. The specific terms of additional future offerings, if any, under this shelf registration statement would be established at the time of such offerings. Pursuant to a common stock and warrant purchase agreement dated August 9, 2017 between the Company and Ally Bridge, an offering of 48,888 shares of the Company’s common stock and a warrant to purchase up to an aggregate of 47,821 shares of common stock was effected at a combined offering price of $45.00 per unit for total gross proceeds to the Company of $2.2 million. The warrant sold in this offering has an exercise price of $45.00 per share, an estimated grant date fair value of approximately $1.5 million, and expires five years from the date of issuance. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of the warrant sold in this offering. As such, the total increase in capital from the sale of the common stock and warrant has been approximately $2.0 million after deducting $0.2 million of associated costs incurred, which were offset against these proceeds under applicable accounting guidance. On January 30, 2018, the Company received net cash proceeds of approximately $13.3 million from the closing of a follow-on public offering of 1,095,153 shares of its common stock and warrants to purchase up to an aggregate of 1,095,153 shares of its common stock at a combined offering price of $13.50 per unit, with $1.4 million of costs directly associated with the offering recorded as an offset to additional paid-in capital under applicable accounting guidance. The warrants sold in this offering have an exercise price of $4.53 per share, which is subject to down round adjustment, an aggregate estimated grant date fair value of $9.7 million (see Note 4) and expire five years from the date of issuance. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering. On August 13, 2018, the Company received net cash proceeds of approximately $10.2 million from closing a rights offering pursuant to its effective registration statement on Form S-1, selling an aggregate of 11,587 units consisting of an aggregate of 11,587 shares of Series A Preferred Stock and 2,549,140 warrants. The warrants are exercisable for one share of our common stock at an exercise price of $4.53 per share, an aggregate estimated grant date fair value of $8.4 million (see Note 4) and expire five years from the date of issuance. The Series A Preferred Stock is convertible to the Company’s common stock at a conversion price of $4.53, includes a right to participate in subsequent right offerings and has a right to participate in stock dividends and splits, if any. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering. On September 20, 2018, the Company completed an offering of 642,438 shares of the Company’s common stock and pre-funded warrants to purchase up to an aggregate of 120,000 shares of its common stock. The shares were sold at a purchase price of $3.285 per share and the pre-funded warrants were sold at a purchase price of $3.275 per pre-funded warrant which represents the per share purchase price for the shares less the $0.01 per share exercise price for each such pre-funded warrant. The net proceeds to the Company from this offering were approximately $2.2 million, after deducting expenses related to the offering including dealer-manager fees and expenses, and excluding any proceeds received upon exercise of any warrants. In addition, in a concurrent private placement, the Company issued to purchasers a warrant to purchase one share of the Company’s common stock for each share and pre-funded warrant purchased for cash in the offering. All warrants issued in this offering have an exercise price of $3.16 per share, are exercisable upon the six-month anniversary of issuance and expire five years from such date.	4. Sales of Equity Securities On December 21, 2015, the Company entered into a common stock purchase agreement with Aspire Capital Fund, LLC, or Aspire Capital, which committed to purchase up to an aggregate of $15.0 million of shares of the Company’s common stock over the 30-month term of the common stock purchase agreement. On November 4, 2016, the Company voluntarily terminated this common stock purchase agreement. Upon execution of the common stock purchase agreement, the Company sold to Aspire Capital 6,944 shares of common stock at $144.00 per share for proceeds of $1,000,000, and concurrently also entered into a registration rights agreement with Aspire Capital, pursuant to which the Company filed a registration statement registering the sale of the shares of the Company’s common stock that were issued to Aspire Capital under the common stock purchase agreement. In consideration for entering into, and concurrently with the execution of, the common stock purchase agreement, the Company issued to Aspire Capital 1,833 shares of its common stock. The proceeds received by the Company under the common stock purchase agreement were used for working capital and general corporate purposes. During the year ended December 31, 2016, the Company submitted purchase notices to Aspire Capital for an aggregate of 5,771 shares of common stock for gross proceeds of approximately $544,000. Costs associated with this offering of approximately $42,000 and $79,000 during the years ended December 31, 2015 and 2016, respectively, were also recorded as an offset to additional paid-in capital under applicable accounting guidance, and as such, the total net increase in capital related to these transactions was approximately $1.4 million. In May 2015, the SEC declared effective a shelf registration statement filed by the Company, which expires in May 2018. The shelf registration statement allows the Company to issue any combination of its common stock, preferred stock, debt securities and warrants from time to time for an aggregate initial offering price of up to $50 million, subject to certain limitations for so long as the Company’s public float is less than $75 million. Pursuant to an exclusive placement agent agreement dated April 25, 2016 between the Company and H.C. Wainwright & Co., LLC, and a securities purchase agreement dated April 29, 2016 between the Company and the purchasers signatory thereto, a public offering of 55,406 shares of the Company’s common stock and warrants to purchase up to an aggregate of 38,784 shares of common stock was effected under this registration statement at a combined offering price of $90.00. All warrants sold in this offering have a per share exercise price of $117.00, are exercisable immediately and expire five years from the date of issuance. The estimated grant date fair value of these warrants of approximately $2.0 million was recorded as an offset to additional paid-in capital upon the closing of this offering (see Note 5). The closing of the sale of these securities to the purchasers occurred on May 4, 2016, pursuant to which the Company received, after deducting $0.7 million of costs directly associated with the offering that were recorded as an offset to additional paid-in capital under applicable accounting guidance, approximately $4.3 million of net cash proceeds. Subsequent to the closing of this offering on May 4, 2016, no warrants sold in this offering have been exercised, with approximately $4.5 million in gross warrant proceeds remaining outstanding and available to be exercised at $117.00 per share until their expiration in May 2021. Pursuant to an exclusive placement agent agreement dated March 28, 2017 between the Company and Roth Capital Partners, LLC as lead placement agent, and WestPark Capital and Chardan Capital as co-placement agents, a securities purchase agreement for a second offering of 144,000 shares of the Company’s common stock was effected under this registration statement at a per share price of $64.50, which closed on March 31, 2017. In a concurrent private placement, the Company sold unregistered warrants to purchase up to an aggregate of 72,000 shares of the Company’s common stock that closed concurrently with the March 2017 offering of common stock sold pursuant the shelf registration statement, of which none have been subsequently exercised. All warrants sold in this offering have a per share exercise price of $75.00 and expire on October 1, 2022. The estimated grant date fair value of these warrants of approximately $2.8 million was recorded as an offset to additional paid-in capital upon the closing of this offering (see Note 5). At the closing of these sales on March 31, 2017, the Company received, after deducting $0.7 million of costs directly associated with the offering that were recorded as an offset to additional paid-in capital under applicable accounting guidance, approximately $8.6 million of net cash proceeds. Pursuant to an exclusive placement agent agreement dated December 5, 2017 between the Company and Dawson James Securities, Inc. as lead placement agent, and WestPark Capital as co-placement agent, a securities purchase agreement for a registered direct offering of 164,166 shares of the Company’s common stock was effected under this registration statement at a per share price of $20.40. The placement agent was issued a warrant to purchase 8,208 shares of common stock at an exercise price of $25.50 per share, which is first exercisable on June 5, 2018 and expires on December 5, 2022. The estimated grant date fair value of this warrant of approximately $0.1 million was recorded as an offset to additional paid-in capital upon the closing of this offering (see Note 5). The closing of the sale of these securities occurred on December 8, 2017, when the Company received approximately $2.9 million of net cash proceeds. The specific terms of additional future offerings, if any, under this shelf registration statement would be established at the time of such offerings. Pursuant to a common stock and warrant purchase agreement dated August 9, 2017 between the Company and Ally Bridge LB Healthcare Master Fund Limited, or Ally Bridge, an offering of 48,888 shares of the Company’s common stock and warrants to purchase up to an aggregate of 47,821 shares of common stock was effected at a combined offering price of $45.00 per unit for total gross proceeds to the Company of $2.2 million. All warrants sold in this offering have a per share exercise price of $45.00, are exercisable immediately and expire five years from the date of issuance. The estimated grant date fair value of this warrant of approximately $1.5 million was recorded as an offset to additional paid-in capital upon the closing of this offering (see Note 5). Subsequent to the closing of this offering, no additional cash proceeds had been received from the exercise of warrants sold in this offering. As such, the total increase in capital as a result of the sale of the common stock and warrants has been approximately $2.0 million after deducting $0.2 million of associated costs incurred, which were offset against these proceeds under applicable accounting guidance. On January 30, 2018, the Company received net cash proceeds of approximately $13.3 million as a result of the closing of a follow-on public offering of 1,095,153 shares of its common stock and warrants to purchase up to an aggregate of 1,095,153 shares of its common stock at a combined offering price of $13.50 per unit. All warrants sold in this offering have an exercise price of $15.00 per share, subject to down round adjustment, are exercisable immediately and expire five years from the date of issuance. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering (see Note 18).

Fair Value Measurement

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurement

4. Fair Value Measurement

The estimated nonrecurring fair value measurements associated with fixed asset purchases recorded as equipment financing obligations totaling approximately $274,000 during the nine months ended September 30, 2018 were based on information provided by vendors, which involved the use of significant unobservable Level 3 inputs.

Other Fair Value Measurements

As of the closing of the Company’s January 30, 2018 offering, the grant date fair value of the warrants issued to purchase up to 1,095,153 shares of common stock were estimated to be approximately $8.82 per share, or a total of approximately $9.7 million. The warrants sold in this offering have an exercise price of $4.53 per share, which is subject to down round adjustment, and expire five years from the date of issuance. The fair value of the warrants was estimated using a Monte Carlo simulation valuation model using Geometric Brownian Motion, incorporating anticipated future financing events, with the following assumptions:

Beginning stock price	$	10.17
Exercise price	$	4.53
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.48	%
Expected life (in years)		5.00
Expected volatility		99.00	%

As of the closing of the Company’s August 13, 2018 rights offering, the grant date fair value of the warrants issued to purchase up to 2,549,140 shares of common stock were estimated to be approximately $3.30 per share, or a total of approximately $8.4 million. The warrants sold in this offering have an exercise price of $4.53 per share and expire five years from the date of issuance. The fair value of the warrants was estimated using a Black-Scholes model, incorporating the following assumptions:

Beginning stock price	$	3.89
Exercise price	$	4.53
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.75	%
Expected life (in years)		5.00
Expected volatility		128.69	%

As of the closing of the Company’s September 20, 2018 offering, the grant date fair value of the warrants issued to purchase up to 762,438 shares of common stock were estimated to be approximately $2.57 per share, or a total of approximately $2.0 million. The warrants sold in this offering have an exercise price of $3.16 per share, and expire five years from the initial exercise date, which is the six month anniversary of the date of issuance. The fair value of the warrants was estimated using a Black-Scholes model, incorporating the following assumptions:

Beginning stock price	$	2.92
Exercise price	$	3.16
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.77	%
Expected life (in years)		5.50
Expected volatility		130.7	%

Also, included in the September 20, 2018 offering the Company issued 120,000 pre-funded warrants. The pre-funded warrants had an intrinsic value of $350,000.

5. Fair Value Measurement

The estimated nonrecurring fair value measurements associated with fixed asset purchases recorded as equipment financing obligations totaling approximately $975,000 and $719,000 during the years ended December 31, 2016 and 2017, respectively, were based on information provided by vendors, which involved the use of significant unobservable Level 3 inputs.

The estimated fair value of the terms of the credit facility entered into with Oxford Finance LLC in April 2014, or the April 2014 Credit Facility, at December 31, 2017 approximated its carrying value, which was determined using a discounted cash flow analysis. The analysis considered interest rates of instruments with similar maturity dates, which involved the use of significant unobservable Level 3 inputs.

Other Fair Value Measurements

As of the closing of the Company’s May 2016 public offering, the estimated grant date fair value of $51.60 per share associated with the warrants to purchase 38,784 shares of common stock issued in this offering, or a total of approximately $2.0 million, was recorded as an offset to additional paid-in capital, and was estimated using a Black-Scholes valuation model with the following assumptions:


Stock price	$	81.00
Exercise price	$	117.00
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		1.23	%
Expected life (in years)		5.00
Expected volatility		90.0	%

As of the closing of the Company’s October 2016 public offering, the estimated grant date fair value of $17.10 per share associated with the warrants to purchase 303,333 shares of common stock issued in this offering, or a total of approximately $5.2 million, was recorded as an offset to additional paid-in capital. Additionally, the underwriters were granted a 30-day option to purchase up to 45,500 additional shares of common stock at a price of $30.993 per share, net of the underwriting discount, and/or additional warrants to purchase up to 45,500 shares of common stock at a price of $0.027 per warrant to cover overallotments, if any. The estimated fair value of the overallotment options of approximately $0.8 million was also recorded as an offset to additional paid-in capital. The fair values of these instruments were estimated using a Black-Scholes valuation model with the following assumptions:


	Overallotment Options			Warrants
Stock price	$	27.90			$	27.90
Exercise price	$	30.993			$	33.00
Expected dividend yield		0.00	%		0.00	%
Discount rate-bond equivalent yield		0.25	%		1.24	%
Expected life (in years)		0.08			5.00
Expected volatility		12.9	%		80.0	%

As of the closing of the Company’s March 31, 2017 offering, the estimated grant date fair value of $39.30 per share associated with the warrants to purchase up to 72,000 shares of common stock issued in this offering, or a total of approximately $2.8 million, was recorded as an offset to additional paid-in capital, and was estimated using a Black-Scholes valuation model with the following assumptions:


Stock price	$	63.90
Exercise price	$	75.00
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		1.93	%
Expected life (in years)		5.00
Expected volatility		80.0	%

As of the closing of the Company’s August 9, 2017 offering, the estimated grant date fair value of $30.90 per share associated with the warrant to purchase up to 47,821 shares of common stock issued in this offering, or a total of approximately $1.5 million, was recorded as an offset to additional paid-in capital, and was estimated using a Black-Scholes valuation model with the following assumptions:


Stock price	$	41.70
Exercise price	$	45.00
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		1.81	%
Expected life (in years)		5.00
Expected volatility		100.0	%

As of the closing of the Company’s December 8, 2017 offering, the estimated grant date fair value of $15.60 per share associated with the warrant to purchase up to 8,208 shares of common stock issued to the placement agent in this offering, or a total of approximately $0.1 million, was recorded as an offset to additional paid-in capital, and was estimated using a Black-Scholes valuation model with the following assumptions:


Stock price	$	22.197
Exercise price	$	25.50
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.09	%
Expected life (in years)		4.50
Expected volatility		100.0	%

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Balance Sheet Details

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Balance Sheet Details

5. Balance Sheet Details

The following provides certain balance sheet details:

	December 31,			September 30,
	2017			2018
Fixed Assets
Machinery and equipment	$	2,841,388		$	2,810,226
Furniture and office equipment		147,976			157,391
Computer equipment and software		1,637,034			1,430,669
Leasehold improvements		553,529			570,174
Financed equipment		2,294,762			2,526,081
Construction in process		2,975			128,377
Total fixed assets, gross		7,477,664			7,622,918
Less accumulated depreciation and amortization		(4,354,097	)		(4,721,924	)
Total fixed assets, net	$	3,123,567		$	2,900,994
Accrued Liabilities
Accrued payroll		224,813			387,162
Accrued vacation		474,953			470,473
Accrued bonuses		375,000			804,281
Accrued sales commissions		104,509			42,168
Current portion of deferred rent		116,681			147,771
Accrued other		129,805			102,115
Total accrued liabilities	$	1,425,761		$	1,953,970

Depreciation expense for the nine-month period ended September 30, 2017 was $394,708 and for the nine months ended September 30, 2018 was $580,366. Depreciation expense for the three months ended September 30, 2017 was $159,552 and for the three-month period ended September 30, 2018 was $223,194.

6. Balance Sheet Details

The following provides certain balance sheet details:


	December 31, 2016			December 31, 2017
Fixed Assets
Machinery and equipment	$	2,728,468		$	2,841,388
Furniture and office equipment		143,726			147,976
Computer equipment and software		620,582			1,637,034
Leasehold improvements		517,968			553,529
Financed equipment		1,559,690			2,294,762
Construction in process		169,896			2,975

		5,740,330			7,477,664
Less accumulated depreciation and amortization		(3,933,999	)		(4,354,097	)

Total fixed assets, net	$	1,806,331		$	3,123,567

Accrued Liabilities
Accrued interest	$	20,776		$	326,602
Accrued payroll		168,727			224,813
Accrued vacation		364,953			474,953
Accrued bonuses		422,868			375,000
Accrued sales commissions		77,844			104,509
Current portion of deferred rent		67,085			116,681
Accrued other		37,783			129,805

Total accrued liabilities	$	1,160,036		$	1,752,363

During the year ended December 31, 2016, non-financed equipment fixed assets with aggregate gross book values and corresponding accumulated depreciation amounts of approximately $77,000 were disposed of, with cash proceeds of approximately $31,000 received upon sale.

April 2014 Credit Facility	9 Months Ended	12 Months Ended
April 2014 Credit Facility	Sep. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
April 2014 Credit Facility	6. April 2014 Credit Facility On April 30, 2014, the Company received net cash proceeds of approximately $4,898,000 pursuant to the execution of the April 2014 Credit Facility. Upon entering into the April 2014 Credit Facility, the Company was required to pay the lender a facility fee of $50,000 in conjunction with the funding of the term loan. The April 2014 Credit Facility was secured by substantially all of the Company’s personal property other than its intellectual property. The term loan under the April 2014 Credit Facility bore interest at an annual rate of 7.95%. The Company was required to make interest-only payments on the term loan through August 1, 2015. The outstanding term loan under the April 2014 Credit Facility began amortizing at the end of the applicable interest-only period, with monthly payments of principal and interest being made by the Company to the lender in consecutive monthly installments following such interest-only period. The term loan under the April 2014 Credit Facility matured on July 1, 2018. Under the original terms of the underlying agreement, the Company was also required to make a final payment to the lender equal to 5.5% of the original principal amount of the term loan funded. A warrant to purchase up to 588 shares of the Company’s common stock at an exercise price of $424.80 per share with a term of 10 years was issued to Oxford Finance LLC on April 30, 2014. Issuance costs of approximately $102,000 associated with the term loan under the April 2014 Credit Facility were recorded as a discount to outstanding debt as of the closing date, resulting in net proceeds of approximately $4,898,000. The estimated fair value of the warrant issued of approximately $233,000 was also recorded as a discount to outstanding debt as of the closing date. The discounts and other issuance costs were amortized to interest expense utilizing the effective interest method over the underlying term of the loan, with a total unamortized discount of approximately $33,000 at December 31, 2017. The effective annual interest rate associated with the April 2014 Credit Facility was 13.87% at both December 31, 2017 and June 30, 2018. A principal payment of approximately $175,000 remained outstanding at June 30, 2018 and was paid on July 1, 2018.	7. April 2014 Credit Facility On April 30, 2014, the Company received net cash proceeds of approximately $4,898,000 pursuant to the execution of the April 2014 Credit Facility. Upon the entry into the April 2014 Credit Facility, the Company was required to pay the lender a facility fee of $50,000 in conjunction with the funding of the term loan. The April 2014 Credit Facility is secured by substantially all of the Company’s personal property other than its intellectual property. Amounts due to Oxford Finance LLC under the April 2014 Credit Facility are callable before maturity by the lender under certain subjective acceleration clauses of the underlying agreement, including changes deemed to be materially adverse by the lender. The term loan under the April 2014 Credit Facility bears interest at an annual rate of 7.95%. The Company was required to make interest-only payments on the term loan through August 1, 2015. The outstanding term loan under the April 2014 Credit Facility began amortizing at the end of the applicable interest-only period, with monthly payments of principal and interest being made by the Company to the lender in consecutive monthly installments following such interest-only period. The term loan under the April 2014 Credit Facility matures on July 1, 2018. Under the original terms of the underlying agreement, the Company is also required to make a final payment to the lender equal to 5.5% of the original principal amount of the term loan funded. At its option, the Company may prepay the outstanding principal balance of the term loan in whole but not in part, subject to a prepayment fee of 1% of any amount prepaid. On June 30, 2016, the Company entered into an amendment of the April 2014 Credit Facility. This amendment required the Company to make interest-only payments on the term loan from July 1, 2016 through September 30, 2016, and also requires an additional final payment of $50,000 to the lender. The terms of the amendment require the amortization of the outstanding amount due under the term loan to commence at the end of the applicable interest-only period, with monthly payments of principal and interest, in arrears, being made by the Company to the lender in consecutive monthly installments following such interest-only period. Additionally, pursuant to the amendment the aggregate outstanding principal amount of the Company’s permitted indebtedness, consisting of capitalized lease obligations and purchase money indebtedness outstanding at any time, was increased to $1.2 million. The June 30, 2016 amendment of the April 2014 Credit Facility was accounted for as a modification of debt under applicable accounting guidance. On June 28, 2017, the Company entered into an amendment of the April 2014 Credit Facility whereby the aggregate outstanding principal amount of the Company’s permitted indebtedness was increased to $3.0 million. The April 2014 Credit Facility includes affirmative and negative covenants applicable to the Company and any subsidiaries created in the future. The affirmative covenants include, among others, covenants requiring the Company to maintain its legal existence and governmental approvals, deliver certain financial reports and maintain insurance coverage. The negative covenants include, among others, restrictions on transferring collateral, incurring additional indebtedness, engaging in mergers or acquisitions, paying dividends or making other distributions, making investments, creating liens, selling assets, and suffering a change in control, in each case subject to certain exceptions. The April 2014 Credit Facility also includes events of default, the occurrence and continuation of which provide Oxford Finance LLC, as collateral agent, with the right to exercise remedies against the Company and the collateral securing the term loan under the April 2014 Credit Facility, including foreclosure against the Company’s properties securing the April 2014 Credit Facility, including its cash. These events of default include, among other things, the Company’s failure to pay any amounts due under the April 2014 Credit Facility, a breach of covenants under the April 2014 Credit Facility, insolvency, a material adverse change, the occurrence of any default under certain other indebtedness in an amount greater than $250,000, and a final judgment against the Company in an amount greater than $250,000. A warrant to purchase up to 588 shares of the Company’s common stock at an exercise price of $424.80 per share with a term of 10 years was issued to Oxford Finance LLC on April 30, 2014. Issuance costs of approximately $102,000 associated with the term loan under the April 2014 Credit Facility were recorded as a discount to outstanding debt as of the closing date, resulting in net proceeds of approximately $4,898,000. The estimated fair value of the warrant issued of approximately $233,000 was also recorded as a discount to outstanding debt as of the closing date. The discounts and other issuance costs are amortized to interest expense utilizing the effective interest method over the underlying term of the loan, with total unamortized discounts of approximately $78,000 and $33,000 remaining at December 31, 2016 and 2017, respectively. The effective annual interest rate associated with the April 2014 Credit Facility was 13.87% at both December 31, 2016 and 2017. As of December 31, 2017, total remaining principal payments of approximately $1,201,000 were due under the April 2014 Credit Facility during the year ending December 31, 2018.

Equipment Financings

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Capital Lease Obligations [Abstract]

Equipment Financings

7. Equipment Financings

The Company leases certain laboratory equipment under arrangements accounted for as capital leases and classified as equipment financings. The financed equipment is depreciated on a straight-line basis over periods ranging from approximately 3 to 7 years. The total gross value of fixed assets capitalized under such financing arrangements was approximately $2,295,000 and $2,526,000 at December 31, 2017 and September 30, 2018, respectively. Total accumulated depreciation related to financed equipment was approximately $759,000 and $1,030,000 at December 31, 2017 and September 30, 2018, respectively. Total depreciation expense related to financed equipment during the three months ended September 30, 2017 and 2018 was approximately $52,000 and $115,000, respectively, and was approximately $160,000 and $271,000 during the nine months ended September 30, 2017 and 2018, respectively.

The following schedule sets forth the remaining future minimum lease payments outstanding under financed equipment arrangements, as well as corresponding remaining sales tax and maintenance obligation payments that are expensed as incurred and due within each respective year ending December 31, as well as the present value of the total amount of the remaining minimum lease payments, as of September 30, 2018:

				Maintenance
	Minimum			and Sales Tax
	Lease			Obligation
	Payments			Payments
2018 (remaining three months)	$	154,538		$	30,237
2019		613,448			88,599
2020		464,152			67,752
2021		303,228			53,252
2022		262,974			53,493
Thereafter		262,952			40,641
Total payments		2,061,292			333,974
Less amount representing interest		(473,166	)		—
Present value of payments	$	1,588,126		$	333,974

The aggregate weighted average effective annual interest rate associated with equipment financings was 13.51% and 12.53% at December 31, 2017 and September 30, 2018, respectively, and the maturity dates on such outstanding arrangements range from February 2019 to September 2024. During the three months ended September 30, 2017 and 2018, total interest expense related to equipment financings of approximately $38,000 and $60,000, respectively, was recorded to the Company’s unaudited condensed statements of operations and comprehensive loss, and approximately $118,000 and $168,000 was recorded during the nine months ended September 30, 2017 and 2018, respectively. At September 30, 2018, the present value of minimum lease payments due within one year was approximately $572,000.

8. Equipment Financings

The Company leases certain laboratory equipment under arrangements accounted for as capital leases and classified as equipment financings. The financed equipment is depreciated on a straight-line basis over periods ranging from 5 to 7 years. The total gross value of fixed assets capitalized under such financing arrangements was approximately $1,560,000 and $2,295,000 at December 31, 2016 and 2017, respectively. Total accumulated depreciation related to financed equipment was approximately $525,000 and $759,000 at December 31, 2016 and 2017, respectively, and total depreciation expense was approximately $119,000 and $234,000, respectively. Fixed asset purchases totaling approximately $975,000 and $719,000 during the years ended December 31, 2016 and 2017, respectively, were recorded as equipment financings. During the year ended December 31, 2016, fixed assets with an aggregate net book value of approximately $270,000, which had previously been recorded as equipment financings with remaining outstanding balances owed totaling approximately $240,000, were effectively disposed of and replaced with upgraded equipment recorded as equipment financings.

On September 15, 2017, and as amended on October 17, 2017, the Company executed an equipment financing commitment with a third-party lender for total proceeds to the Company of approximately $151,000, which was funded by the lender on November 2, 2017. Under the terms of the amended equipment financing agreement, which was accounted for as a sale-leaseback transaction, fixed assets previously purchased by the Company with aggregate gross and net book values of approximately $167,000 and $162,000, respectively, were granted as a security interest to the third-party lender, with the principal balance plus interest to be repaid in 36 monthly installments of $4,884 totaling approximately $176,000 through October 2020.

During the year ended December 31, 2017, certain machinery and equipment with aggregate gross, accumulated depreciation, and net book values of approximately $189,000, $155,000 and $34,000, respectively, were exchanged with a lender as partial payment on an outstanding equipment financing obligation balance.

The following schedule sets forth the remaining future minimum lease payments outstanding under financed equipment arrangements, as well as corresponding remaining sales tax and maintenance obligation payments that are expensed and accrued as incurred and due within each respective year ending December 31, as well as the present value of the total amount of the remaining minimum lease payments as of December 31, 2017:


			Maintenance
	Minimum		and Sales Tax
	Lease		Obligation
	Payments		Payments
2018	$	438,737	$	63,602
2019		460,166		67,394
2020		406,868		55,205
2021		302,229		44,281
2022		268,018		38,479
Thereafter		253,951		39,881

Total payments		2,129,969		308,842
Less amount representing interest		570,914		—

Present value of payments	$	1,559,055	$	308,842

The aggregate weighted average effective annual interest rate related to the equipment financings was 13.18% and 13.51% at December 31, 2016 and 2017, respectively, and the maturity dates on such outstanding arrangements range from June 2018 to September 2024. During the years ended December 31, 2016 and 2017, total interest expense related to equipment financings of $49,000 and $171,000, respectively, was recorded to the Company’s statement of operations and comprehensive loss. At December 31, 2017, the present value of minimum lease payments due within one year was approximately $409,000.

On January 26, 2018, the Company executed a lease agreement with a third-party lender to finance approximately $250,000 of planned fixed asset purchases. Under the terms of the lease agreement, upon lease commencement and repayment, which occurs once the Company has financed equipment purchases for the full amount available under the lease agreement, the Company is required to make 22 payments of $11,081 per month during the initial term of the agreement, subject to adjustment in the event of an increase in three-year Treasury note rates prior to lease commencement and repayment. Until lease commencement and repayment, the Company is required to pay pro-rated equipment rental charges of any equipment financed under this lease. The Company expects lease commencement and repayment to occur by June 30, 2018. Through the date that these financial statements were available to be issued, approximately $78,000 of equipment purchases had been financed under this lease agreement (see Note 18).

Stock-Based Compensation

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

8. Stock-Based Compensation

Equity Incentive Plans

The Company maintains two equity incentive plans: The Amended and Restated 2013 Equity Incentive Plan, or the 2013 Plan, and the 2007 Equity Incentive Plan, or the 2007 Plan. The 2013 Plan includes a provision that shares available for grant under the Company’s 2007 Plan become available for issuance under the 2013 Plan and are no longer available for issuance under the 2007 Plan. At the Company’s annual meeting of stockholders held on June 28, 2018, the Company’s stockholders approved amendments to the 2013 Plan, which included an increase in the number of non-inducement shares of common stock authorized for issuance under the 2013 Plan by 146,666 shares. As of September 30, 2018, 59,511 shares of the Company’s common stock were authorized exclusively for the issuance of stock awards to employees who have not previously been an employee or director of the Company, except following a bona fide period of non-employment, as an inducement material to the individual’s entering into employment with the Company, as defined under applicable Nasdaq Listing Rules. As of September 30, 2018, under all plans, a total of 264,098 non-inducement shares were authorized for issuance, 69,449 shares had been issued with 57,863 non-inducement stock options and restricted stock units, or RSUs, underlying outstanding awards, and 194,649 non-inducement shares were available for grant. As of September 30, 2018, 60,268 inducement shares had been issued under the 2013 Plan, with 59,434 inducement stock options and RSUs underlying outstanding awards and 0 inducement shares available for grant.

Stock Options

A summary of stock option activity for the nine months ended September 30, 2018 is as follows:

						Weighted
						Average
				Weighted		Remaining
	Number of			Average Exercise		Contractual
	Shares			Price Per Share		Term in Years
Outstanding at December 31, 2017		81,482		$	113.68		8.80
Granted		58,994		$	2.96		7.43
Exercised		—			—
Cancelled/forfeited/expired		(25,835	)	$	45.83		8.68
Outstanding at September 30, 2018		114,641		$	72.02		8.79
Vested and unvested expected to vest at September 30, 2018		112,280		$	73.23		8.77

The intrinsic values of options outstanding, options exercisable, and options vested and unvested expected to vest at December 31, 2017 and September 30, 2018 were each approximately zero.

The assumptions used in the Black-Scholes pricing model for stock options granted during the three and nine months ended September 30, 2018 were as follows:

Stock and exercise prices	$2.75 - $6.00
Expected dividend yield		0.00%
Discount rate-bond equivalent yield	2.73% – 2.97%
Expected life (in years)	5.00 – 5.96
Expected volatility	100% - 120%

On May 2, 2017, the Company’s Board of Directors approved the issuance of an aggregate of 18,333 performance stock options to be granted on May 31, 2017 to certain of the Company’s employees and all of its executive officers pursuant to the 2013 Plan, of which 6,666 performance stock options were granted to the Company’s CEO, 3,333 performance stock options were granted to its CFO, and 2,500 performance stock options were granted to each of its Chief Scientific Officer and Senior Medical Director. Each performance stock option granted on May 31, 2017 had an exercise price of $45.00 per share and an estimated grant date fair value of $29.70 per share. On July 6, 2017, the Company’s Compensation Committee of the Board of Directors approved the issuance of an aggregate of 2,500 performance stock options to be granted on July 31, 2017 to certain of the Company’s employees pursuant to the 2013 Plan, of which 83 performance stock options were forfeited by December 31, 2017. Each performance stock option granted on July 31, 2017 had an exercise price of $41.70 per share and an estimated grant date fair value of $24.90 per share. The vesting of each of the performance stock options granted during the year ended December 31, 2017 was to be determined by the Company’s Board of Directors or Compensation Committee of the Board of Directors upon the Company’s achievement of specified corporate goals for 2017. During the nine months ended September 30, 2018, none of the performance option awards granted during the year ended December 31, 2017 were declared vested by the Company’s Compensation Committee of the Board of Directors, and the 20,750 shares underlying the remaining outstanding performance stock option awards at December 31, 2017 were forfeited.

Restricted Stock

A summary of RSU activity for the nine months ended September 30, 2018 is as follows:

				Weighted
	Number of			Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2017		12,026		$	56.10
Granted		—			—
Vested and issued		(5,833	)	$	45.00
Forfeited		(5,833	)	$	45.00
Outstanding at September 30, 2018		360		$	415.80
Vested and unvested expected to vest at September 30, 2018		360		$	415.80

At September 30, 2018, the intrinsic values of RSUs outstanding and RSUs unvested and expected to vest were each approximately $1,000. Of the 360 RSUs outstanding at September 30, 2018, all were fully vested.

On May 2, 2017, the Company’s Board of Directors approved the issuance of an aggregate of 5,833 time-based RSUs and 5,833 performance RSUs to be granted on May 31, 2017 to certain of the Company’s employees and all of its executive officers pursuant to the 2013 Plan, of which 1,666 time-based RSUs and 833 performance RSUs were granted to its CEO, and 833 time-based RSUs and 833 performance RSUs were granted to each of its CFO, Chief Scientific Officer, and Senior Medical Director. Each RSU granted on May 31, 2017 had a grant date fair value of $45.00 per share. Vesting of the time-based RSUs granted on May 31, 2017 occurred on the one-year anniversary of the vesting commencement date, or May 2, 2018, while vesting of the performance RSUs was to be determined by the Company’s Board of Directors or its Compensation Committee of the Board of Directors upon the achievement of specified corporate goals for 2017. During the nine months ended September 30, 2018, none of the performance RSUs granted on May 31, 2017 were declared vested by the Company’s Compensation Committee of the Board of Directors, and the 1,666 shares underlying these awards were forfeited.

Stock-based Compensation Expense

The following table presents the effects of stock-based compensation related to equity awards to employees and nonemployees on the unaudited condensed statements of operations and comprehensive loss during the periods presented:

	For the three months ended				For the nine months ended
	September 30,				September 30,
	2017		2018		2017		2018
Stock Options
Cost of revenues	$	59,720	$	10,150	$	133,105	$	37,150
Research and development expenses		53,405		30,247		121,834		103,267
General and administrative expenses		178,671		57,162		528,406		243,593
Sales and marketing expenses		40,181		15,440		100,327		63,494
Total expenses related to stock options		331,977		112,999		883,672		447,504
RSUs
Cost of revenues		20,417		-		58,717		(18,802	)
Research and development expenses		20,418		-		57,490		13,576
General and administrative expenses		74,521		-		160,927		54,303
Sales and marketing expenses		28,355		-		71,343		15,348
Total stock-based compensation	$	475,688	$	112,999	$	1,232,149	$	511,929

Stock-based compensation expense was recorded net of estimated forfeitures of 0% - 8% per annum during each of the three and nine months ended September 30, 2017 and 2018. As of September 30, 2018, total unrecognized share-based compensation expense related to unvested stock options and RSUs, adjusted for estimated forfeitures, was approximately $900,474 and is expected to be recognized over a weighted-average period of approximately 2.4 years.

10. Stock-Based Compensation

Equity Incentive Plans

The Company maintains two equity incentive plans: The Amended and Restated 2013 Equity Incentive Plan, or the 2013 Plan, and the 2007 Equity Incentive Plan, or the 2007 Plan. The 2013 Plan includes a provision that shares available for grant under the Company’s 2007 Plan become available for issuance under the 2013 Plan and are no longer available for issuance under the 2007 Plan. On July 25, 2016, the Company’s Board of Directors approved an amendment to the 2013 Plan to reserve 33,333 shares on a pre-reverse stock split basis, or 11,111 shares on a post-reverse stock split basis, of the Company’s common stock exclusively for the grant of stock awards to employees who have not previously been an employee or director of the Company, except following a bona fide period of non-employment, as an inducement material to the individual’s entering into employment with the Company, as defined under applicable Nasdaq Listing Rules. In conjunction with the one-for-three reverse split of the Company’s common stock effected on September 29, 2016, the number of non-inducement shares authorized under all plans decreased from 102,295 to 34,098 shares, and the number of inducement shares authorized under the 2013 Plan decreased from 33,333 shares to 11,111 shares. At the Company’s annual meeting of stockholders held on May 2, 2017, the Company’s stockholders approved amendments to the 2013 Plan, which included an increase in the number of non-inducement shares of common stock authorized for issuance under the 2013 Plan by 83,333. As of December 31, 2017, under all plans, a total of 117,431 non-inducement shares were authorized for issuance, 94,982 shares had been issued with 89,238 non-inducement stock options and restricted stock units, or RSUs, underlying outstanding awards, and 22,499 non-inducement shares were available for grant. As of December 31, 2017, a total of 11,111 inducement shares were authorized for issuance, 5,268 inducement shares had been issued with 4,434 inducement stock options and RSUs underlying outstanding awards, and 5,842 inducement shares were available for grant under the 2013 Plan.

Stock Options

Non-performance options granted under either plan vest over a maximum period of four years and expire ten years from the date of grant. Non-performance options generally vest either (i) over four years, 25% on the one-year anniversary of the date of grant and monthly thereafter for the remaining three years; or (ii) over four years, monthly vesting beginning month-one after the grant and monthly thereafter.

The fair value of stock options is determined on the date of grant using the Black-Scholes valuation model. For non-performance awards, such value is recognized as expense over the requisite service period, net of estimated forfeitures, using the straight-line method. The amount and timing of compensation expense recognized for performance awards is based on management’s estimate of the most likely outcome and when the achievement of the performance objectives is probable. The determination of the fair value of stock options is affected by the Company’s stock price, as well as assumptions regarding a number of complex and subjective variables. The volatility assumption is based on a combination of the historical volatility of the Company’s common stock and the volatilities of similar companies over a period of time equal to the expected term of the stock options. The volatilities of similar companies are used in conjunction with the Company’s historical volatility because of the lack of sufficient relevant history for the Company’s common stock equal to the expected term. The expected term of employee stock options represents the weighted-average period the stock options are expected to remain outstanding. The expected term assumption is estimated based primarily on the options’ vesting terms and remaining contractual life and employees’ expected exercise and post-vesting employment termination behavior. The risk-free interest rate assumption is based upon observed interest rates on the grant date appropriate for the term of the employee stock options. The dividend yield assumption is based on the expectation of no future dividend payouts by the Company.

The assumptions used in the Black-Scholes pricing model for options granted during the years ended December 31, 2016 and 2017 are as follows:


	2016	2017
Stock and exercise prices	$23.25 - $120.60	$20.817 - $63.90
Expected dividend yield	0.00%	0.00%
Discount rate-bond equivalent yield	0.99% - 2.11%	1.79% - 2.27%
Expected life (in years)	5.13 - 6.08	5.12 - 6.09
Expected volatility	80.0% - 90.0%	70.0% - 90.0%

Using the assumptions described above, with stock and exercise prices being equal on date of grant, the weighted-average estimated fair value of options granted in 2016 and 2017 were approximately $53.70 and $30.60 per share, respectively.

A summary of stock option activity for the years ended December 31, 2016 and 2017 is as follows:


	Number of Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term in Years
Outstanding at December 31, 2015		23,788		$	330.90		8.8

Granted		9,679		$	75.30
Exercised		—			—
Cancelled/forfeited/expired		(3,579	)	$	239.70

Outstanding at December 31, 2016		29,888		$	264.00		8.5

Granted		58,501		$	44.70
Exercised		—			—
Cancelled/forfeited/expired		(6,746	)	$	143.10

Outstanding at December 31, 2017		81,643		$	113.70		8.8

Vested and unvested expected to vest, December 31, 2017		59,142		$	140.10		8.6

The intrinsic values of options outstanding, options exercisable, and options vested and unvested expected to vest at December 31, 2016 and 2017 were each zero.

On August 31, 2015, the Company’s Board of Directors approved the issuance of 1,111 performance stock options with an estimated grant date fair value of $132.00 per share and an exercise price of $180.90 per share to its Chief Executive Officer, or CEO, pursuant to the 2013 Plan. On February 29, 2016, the Company’s Board of Directors approved the issuance of 1,111 performance stock options with an estimated grant date fair value of $86.10 per share and an exercise price of $120.60 per share to its CEO pursuant to the 2013 Plan. Vesting of these stock options was based on the Company’s achievement of specified objectives by December 31, 2016 as determined by the Company’s Board of Directors or the Compensation Committee of the Board of Directors. During the year ended December 31, 2017, 211 of the performance stock options granted on August 31, 2015 and 333 of the performance stock options granted on February 29, 2016 were declared vested by the Company’s Board of Directors, and the remaining 1,677 shares underlying these awards were forfeited.

On July 25, 2016, the Company entered into an employment agreement with its new Chief Financial Officer, Senior Vice President of Operations and Secretary, or CFO. Pursuant to the terms of this employment agreement, on July 29, 2016 the CFO was granted inducement stock option awards with an exercise price of $58.50 per share to purchase up to (i) 2,222 shares of the Company’s common stock with an estimated grant date fair value of $43.50 per share, 25% of which vested on the one-year anniversary of the commencement of the CFO’s employment with the Company, and remainder of which will vest in equal monthly installments over the following three years, and (ii) 1,111 shares of the Company’s common stock with an estimated grant date fair value of $37.80 per share, which vested upon the Company’s achievement of specified corporate goals for 2016 and the consummation of a specified financing transaction. During the year ended December 31, 2017, 546 shares of the performance option award granted on July 29, 2016 were declared vested by the Company’s Board of Directors, and the remaining 565 shares underlying this award were forfeited.

On May 2, 2017, the Company’s Board of Directors approved the issuance of an aggregate of 18,333 performance stock options to be granted on May 31, 2017 to certain of the Company’s employees and all of its executive officers pursuant to the 2013 Plan, of which 6,666 performance stock options were granted to the Company’s CEO, 3,333 performance stock options were granted to its CFO, and 2,500 performance stock options were granted to each of its Chief Scientific Officer and Senior Medical Director. Each performance stock option granted on May 31, 2017 has an exercise price of $45.00 per share and an estimated grant date fair value of $29.70 per share. On July 6, 2017, the Company’s Compensation Committee of the Board of Directors approved the issuance of an aggregate of 2,500 performance stock options to be granted on July 31, 2017 to certain of the Company’s employees pursuant to the 2013 Plan, of which 83 performance stock options were forfeited by December 31, 2017. Each performance stock option granted on July 31, 2017 has an exercise price of $41.70 per share and an estimated grant date fair value of $24.90 per share. Each of the performance stock options granted during the year ended December 31, 2017 were subject to continuing service with vesting as determined by the Company’s Board of Directors or Compensation Committee of the Board of Directors upon the Company’s achievement of specified corporate goals for 2017. Subsequent to the year ended December 31, 2017, none of the performance option awards granted during the year ended December 31, 2017 were declared vested by the Company’s Compensation Committee of the Board of Directors, and the 20,750 shares underlying the remaining outstanding performance stock option awards at December 31, 2017 were forfeited.

Restricted Stock

The fair value of RSUs awarded under either plan is determined by the closing price of the Company’s common stock on the date of grant. For non-performance RSUs, such value is recognized as expense over the requisite service period, net of estimated forfeitures, using the straight-line method. The amount and timing of compensation expense recognized for RSUs is based on management’s estimate of the most likely outcome and when the achievement of the performance objectives is probable.

A summary of RSU activity during 2016 and 2017 is as follows:


				Weighted
	Number of			Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2015		858		$	453.60

Granted		5,527		$	58.80
Vested and issued		(148	)	$	481.50
Forfeited		(429	)	$	400.20

Outstanding at December 31, 2016		5,808		$	80.40

Granted		11,666		$	45.00
Vested and issued		(5,194	)	$	58.80
Forfeited		(250	)	$	63.60

Outstanding at December 31, 2017		12,030		$	56.10

Vested and unvested expected to vest, December 31, 2017		6,197		$	66.90

On June 12, 2014, the Company’s Board of Directors approved the grant of 494 RSUs with a grant date fair value of $481.50 per share to its CEO pursuant to the 2013 Plan. Vesting of these RSUs was based on the Company’s achievement of specified objectives by December 31, 2015 as determined by the Company’s Board of Directors or the Compensation Committee of the Company’s Board of Directors. During the year ended December 31, 2016, a total of 148.30 RSUs were declared vested by the Company’s Board of Directors and issued to its CEO in satisfaction of the June 12, 2014 RSU award, and the remaining 346 shares underlying this award were forfeited.

The RSUs granted during the year ended December 31, 2016 vested fully on the one year anniversary of the date of grant, and was subject to continuing service by the holders of such RSUs. At December 31, 2017, the intrinsic values of RSUs outstanding and RSUs unvested and expected to vest were approximately $250,000 and $129,000, respectively.

On July 6, 2016, the Compensation Committee of the Company’s Board of Directors approved retention RSUs for an aggregate of 1,944 shares of common stock to three of the Company’s executive officers pursuant to the 2013 Plan, including retention RSUs for 833 shares of common stock to its CEO. Each of these retention RSUs has a grant date fair value of $55.80 per share for a grant date fair value of approximately $108,000 to all three officers, in aggregate. These retention RSUs vested fully on the one year anniversary of the date of grant, and were subject to continuing service by the holders of such RSUs.

Pursuant to the terms of the Company’s employment agreement with its CFO dated July 25, 2016, the CFO was granted an inducement RSU award on July 29, 2016 covering 833 shares of the Company’s common stock with a grant date fair value of $58.50 per share, 100% of which vested on the one-year anniversary of the commencement of the CFO’s employment with the Company.

On May 2, 2017, the Company’s Board of Directors approved the issuance of an aggregate of 5,833 time-based RSUs and 5,833 performance RSUs to be granted on May 31, 2017 to certain of the Company’s employees and all of its executive officers pursuant to the 2013 Plan, of which 1,666 time-based RSUs and 833 performance RSUs were granted to its CEO, and 833 time-based RSUs and 833 performance RSUs were granted to certain other executive officers. Each RSU granted on May 31, 2017 has a grant date fair value of $45.00 per share. Vesting of the time-based RSUs granted on May 31, 2017 is subject to continuing service and occurs on the one year anniversary of the vesting commencement date, or May 2, 2018, while the performance RSUs were subject to continuous service and vesting was as determined by the Company’s Board of Directors or its Compensation Committee of the Board of Directors upon the achievement of specified corporate goals for 2017. Subsequent to the year ended December 31, 2017, none of the performance RSUs granted on May 31, 2017 were declared vested by the Company’s Compensation Committee of the Board of Directors, and the 5,833 shares underlying these awards were forfeited.

Stock-based Compensation Expense

The following table presents the effects of stock-based compensation related to equity awards to employees and nonemployees on the statement of operations during the periods presented:


	Years Ended December 31,
	2016		2017
Stock Options
Cost of revenues	$	115,266	$	142,400
Research and development expenses		123,330		143,300
General and administrative expenses		1,071,490		575,741
Sales and marketing expenses		142,741		68,381

Total expenses related to stock options		1,452,827		929,822
RSUs
Cost of revenues		32,338		48,745
Research and development expenses		30,261		55,941
General and administrative expenses		38,274		160,937
Sales and marketing expenses		40,247		52,036

Total stock-based compensation	$	1,593,947	$	1,247,481

Stock-based compensation expense was recorded net of estimated forfeitures of 0%—8% per annum during the years ended December 31, 2016 and 2017. As of December 31, 2017, total unrecognized share-based compensation expense related to unvested stock options and RSUs, adjusted for estimated forfeitures, was approximately $1,586,000, and expected to be recognized over a weighted-average period of approximately 2.5 years.

Common Stock Warrants Outstanding

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Other Liabilities Disclosure [Abstract]

Common Stock Warrants Outstanding

9. Common Stock Warrants Outstanding

A summary of equity-classified common stock warrant activity for the nine months ended September 30, 2018 is as follows:

					Average
			Weighted		Remaining
	Number of		Average Exercise		Contractual
	Shares		Price Per Share		Term in Years
Outstanding at December 31, 2017		288,196	$	78.86		4.0
Issued		4,406,731	$	3.95
Exercised		—		—
Expired		—		—
Outstanding at September 30, 2018		4,814,927	$	5.44		4.7

11. Common Stock Warrants Outstanding

A summary of equity-classified common stock warrant activity, for warrants other than those underlying unexercised overallotment option warrants, during 2016 and 2017 is as follows:


						Average
				Weighted		Remaining
	Number of			Average Exercise		Contractual
	Shares			Price Per Share		Term in Years
Outstanding at December 31, 2015		26,140		$	335.40		3.8

Issued		363,021		$	42.00
Exercised		—			—
Expired		(1,696	)	$	900.00

Outstanding at December 31, 2016		387,465		$	57.90		4.6

Issued		128,029		$	60.60
Exercised		(227,228	)	$	33.00
Expired		—			—

Outstanding at December 31, 2017		288,266		$	78.90		4.0

Further information about equity-classified common stock warrants outstanding at December 31, 2017 is as follows:


Weighted Average Exercise Price			Total Shares Outstanding		Weighted Average Contractual Life (in years)
$	25.50			8,208		4.9
$	33.00			97,009		3.8
$	45.00			47,821		4.6
$	75.00			72,000		4.7
$	117.00			38,784		3.3
$	140.40			19,371		2.1
$	891.60			5,071		1.7

		288,264

All warrants outstanding at December 31, 2017 are exercisable, except for the 8,208 warrants issued on December 8, 2017, which are first exercisable on June 5, 2018 and expire on December 5, 2022.

The intrinsic value of equity-classified common stock warrants outstanding at December 31, 2017 was zero.

On January 30, 2018, the Company issued warrants to purchase up to an aggregate of 1,095,153 shares of its common stock, which have an exercise price of $15.00 per share, subject to down round adjustment, are exercisable immediately and expire five years from the date of issuance (see Note 18).

Net Loss per Common Share

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Earnings Per Share [Abstract]

Net Loss per Common Share

10. Net Loss per Common Share

Basic and diluted net loss per common share is determined by dividing net loss applicable to common shareholders by the weighted-average common shares outstanding during the period. Because there is a net loss attributable to common shareholders for the three and nine months ended September 30, 2017 and 2018, the outstanding RSUs, warrants, and common stock options have been excluded from the calculation of diluted loss per common share because their effect would be anti-dilutive. Based on review of the applicable guidance, the 120,000 prefunded warrants that were issued in the September 20, 2018 registered direct offering with an exercise price of $0.01 are considered common stock equivalents and are included in the calculation of basic and diluted loss per share. In other periods presented, the weighted-average shares used to calculate both basic and diluted loss per share are the same.

The following potentially dilutive securities have been excluded from the computations of diluted weighted-average shares outstanding for the periods presented, as they would be anti-dilutive:

	For the three and nine months ended
	September 30,
	2017		2018
Preferred warrants outstanding (number of common stock equivalents)		17		17
Common warrants outstanding		280,058		4,814,927
RSUs outstanding		12,030		360
Common options outstanding		82,810		114,641
Total anti-dilutive common share equivalents		374,915		4,929,945

12. Net Loss per Common Share

The following potentially dilutive securities have been excluded from the computations of diluted weighted-average shares outstanding for the periods presented, as they would be anti-dilutive:


	For the year ended
	December 31,
	2016		2017
Preferred warrants outstanding (number of common stock equivalents)		17		17
Common warrants outstanding		387,465		288,266
RSUs outstanding		5,808		12,030
Common options outstanding		29,888		81,642

Total anti-dilutive common share equivalents		423,178		381,958

Commitments and Contingencies

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

11. Commitments and Contingencies

In the normal course of business, the Company may be involved in legal proceedings or threatened legal proceedings. The Company is not party to any legal proceedings or aware of any threatened legal proceedings that are expected to have a material adverse effect on its financial condition, results of operations or liquidity.

In February 2016, the Company signed a firm, non-cancelable, and unconditional commitment in an aggregate amount of $1,062,500 with a vendor to purchase certain inventory items, payable in minimum quarterly amounts of $62,500 through May 2020. At September 30, 2018, a balance of approximately $404,000 remained outstanding under this purchase commitment.

16. Commitments and Contingencies

Operating Leases

The Company leases office, laboratory, and warehouse space at its San Diego, California facility under a non-cancelable operating lease. The initial lease was for an eight-year term expiring in 2012. In November 2011, the Company extended the lease term through October 31, 2018 and expanded the original premises by 9,849 square feet. Under the amended lease, the landlord delivered the expanded premises in May 2013. In September 2013, the Company extended the lease term through July 31, 2020. The Company records rent expense on a straight-line basis over the life of the lease and records the excess of expense over the amounts paid as deferred rent. During each of the years ended December 31, 2016 and 2017, total rent expense recorded in the Company’s statements of operations and comprehensive loss was approximately $1,272,000.

The future minimum lease payments under the amended lease agreement as December 31, 2017 are as follows:


2018	$	1,388,705
2019		1,430,366
2020		855,136
Thereafter		—

Total	$	3,674,207

Purchase Commitment

In February 2016, the Company signed a firm, non-cancelable, and unconditional commitment in an aggregate amount of $1,062,500 with a vendor to purchase certain inventory items, payable in minimum quarterly amounts of $62,500 through May 2020. At December 31, 2017, a total of approximately $611,000 remained outstanding under this purchase commitment.

Financed Equipment Maintenance and Sales Tax Obligations

During the years ended December 31, 2016 and 2017, total expense recorded in the Company’s statement of operations and comprehensive loss for sales tax and maintenance obligations associated with equipment financing arrangements was approximately $32,000 and $79,000, respectively. At December 31, 2017, approximately $46,000 of such sales tax and maintenance obligations incurred but not paid were recorded in accrued other liabilities in the Company’s balance sheet (see Note 6). Future payments totaling approximately $309,000 for sales tax and maintenance obligations associated with financed equipment were due under equipment financing arrangements at December 31, 2017, which will be expensed as incurred (see Note 8).

Legal Proceedings

In the normal course of business, the Company may be involved in legal proceedings or threatened legal proceedings. The Company is not party to any legal proceedings or aware of any threatened legal proceedings which are expected to have a material adverse effect on its financial condition, results of operations or liquidity.

Related Party Transactions	9 Months Ended	12 Months Ended
Related Party Transactions	Sep. 30, 2018	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	12. Related Party Transactions A member of the Company’s management is the controlling person of Aegea Biotechnologies, Inc., or Aegea. On September 2, 2012, the Company entered into an Assignment and Exclusive Cross-License Agreement, or the Cross-License Agreement, with Aegea. The Company received a payment of approximately $15,000 during the year ended December 31, 2017, as well as a payment of approximately $19,000 during the nine months ended September 30, 2018, from Aegea as reimbursements for shared patent costs under the Cross-License Agreement. There were no payments received on this arrangement during the quarter ended September 30, 2018. Pursuant to a sublease agreement dated March 30, 2015, the Company subleased 9,849 square feet, plus free use of an additional area, of its San Diego facility to an entity affiliated with the Company’s non-executive Chairman for $12,804 per month, with a refundable security deposit of $12,804 received from the subtenant. The initial term of the sublease expired on July 31, 2015 and was subject to renewal on a month-to-month basis thereafter. On February 1, 2017, the Company received notice from the subtenant terminating the sublease effective March 31, 2017. During the year ended December 31, 2017, the total amount of the $12,804 security deposit previously received from the subtenant was applied against approximately $16,000 in additional rents owed as a result of the subtenant continuing to occupy the subleased areas beyond March 31, 2017, and the balance of approximately $3,200 due to the Company was waived. A total of approximately $51,000 and $51,000 in rental income was recorded to other income/(expense) in the Company’s statement of operations and comprehensive loss during the nine months ended September 30, 2017 and the year ended December 31, 2017, respectively. There was no income or expense recorded in the three and nine months ended September 30, 2018 related to this sublease.	15. Related Party Transactions Three members of the Company’s Board of Directors participated in its public offering in May 2016, purchasing an aggregate of 1,944 shares of the Company’s common stock and warrants to purchase up to an aggregate of 1,361 shares of its common stock for total gross proceeds to the Company of $175,000. Additionally, a trust affiliated with Claire K.T. Reiss, who at the time was the beneficial owner of more than 10% of the Company’s outstanding common stock, participated in the Company’s public offering in May 2016, purchasing 6,825 shares of its common stock and warrants to purchase up to 4,777 shares of its common stock for total gross proceeds to the Company of $614,273 (see Note 4). Seven members of the Company’s Board of Directors, including its CEO and all three of the Company’s other executive officers, participated in the Company’s public offering in October 2016, purchasing an aggregate of 17,802 shares of common stock and warrants to purchase up to an aggregate of 17,802 shares of common stock for total gross proceeds to the Company of approximately $587,000. Additionally, a trust affiliated with Claire K.T. Reiss, who at the time was the beneficial owner of more than 10% of the Company’s outstanding common stock, participated in the Company’s public offering in October 2016, purchasing 7,575 shares of its common stock and warrants to purchase up 7,575 shares of its common stock for total gross proceeds to the Company of approximately $250,000. Further, several of the Company’s employees and one of its consultants participated in the Company’s public offering in October 2016, purchasing an aggregate of 2,636 shares of its common stock and warrants to purchase up to an aggregate of 2,636 shares of its common stock for total aggregate gross proceeds to the Company of approximately $87,000. A member of the Company’s management is the controlling person of Aegea Biotechnologies, Inc., or Aegea. On September 2, 2012, the Company entered into an Assignment and Exclusive Cross-License Agreement, or the Cross-License Agreement, with Aegea. The Company received payments totaling approximately $19,000 and $15,000 during the years ended December 31, 2016 and 2017, respectively, from Aegea as reimbursements for shared patent costs under the Cross-License Agreement. Pursuant to a sublease agreement dated March 30, 2015, the Company subleased 9,849 square feet, plus free use of an additional area, of its San Diego facility to an entity affiliated with the Company’s non-executive Chairman for $12,804 per month, with a refundable security deposit of $12,804 received from the subtenant. The initial term of the sublease expired on July 31, 2015 and was subject to renewal on a month-to-month basis thereafter. On February 1, 2017, the Company received notice from the subtenant terminating the sublease effective March 31, 2017. During the year ended December 31, 2017, the total amount of the $12,804 security deposit previously received from the subtenant was applied against approximately $16,000 in additional rents owed as a result of the subtenant continuing to occupy the subleased areas beyond March 31, 2017, and the balance of approximately $3,200 due to the Company was waived. A total of approximately $154,000 and $51,000 in rental income was recorded to other income/(expense) in the Company’s statement of operations and comprehensive loss during the years ended December 31, 2016 and 2017, respectively.

The Company and Business Activities	12 Months Ended
The Company and Business Activities	Dec. 31, 2017
Accounting Policies [Abstract]
The Company and Business Activities	1. The Company and Business Activities The Company was founded in California in May 1997 and is an early stage molecular oncology diagnostics company that develops and commercializes proprietary circulating tumor cell, or CTC, and circulating tumor DNA, or ctDNA, assays utilizing a standard blood sample, or liquid biopsy. The Company’s current and planned assays are intended to provide information to aid healthcare providers to identify specific oncogenic alterations that may qualify a subset of cancer patients for targeted therapy at diagnosis, progression or for monitoring in order to identify specific resistance mechanisms. Sometimes traditional procedures, such as surgical tissue biopsies, result in tumor tissue that is insufficient and/or unable to provide the molecular subtype information necessary for clinical decisions. The Company’s assays, performed on blood, have the potential to provide more contemporaneous information on the characteristics of a patient’s disease when compared with tissue biopsy and radiographic imaging. Additionally, commencing in October 2017, the Company’s pathology partnership program, Empower TC, provides the unique ability for pathologists to participate in the interpretation of liquid biopsy results and is available to pathology practices and hospital systems throughout the United States. Further, the Company’s proprietary blood collection tubes, which allow for the intact transport of liquid biopsy samples for research use only from regions around the world, are anticipated to be sold to laboratory supply distributors commencing in 2018. The Company operates a clinical laboratory that is CLIA-certified (under the Clinical Laboratory Improvement Amendment of 1988) and CAP-accredited (by the College of American Pathologists), and manufactures cell enrichment and extraction microfluidic channels, related equipment and certain reagents to perform the Company’s diagnostic assays in a facility located in San Diego, California. CLIA certification and accreditation are required before any clinical laboratory may perform testing on human specimens for the purpose of obtaining information for the diagnosis, prevention, treatment of disease, or assessment of health. The assays the Company offers are classified as laboratory developed tests under the CLIA regulations. In July 2013, the Company effected a reincorporation to Delaware by merging itself with and into Biocept, Inc., a Delaware corporation, which had been formed to be and was a wholly-owned subsidiary of the Company since July 23, 2013. On July 6, 2018, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s Certificate of Amendment of Certificate of Incorporation to effect a one-for-thirty reverse stock split of the Company’s outstanding common stock. As such, all references to share and per share amounts in these unaudited condensed financial statements and accompanying notes have been retroactively restated to reflect the one-for-thirty reverse stock split, except for the authorized number of shares of the Company’s common stock of 150,000,000 shares, which was not affected by the one-for-thirty reverse stock split.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

3. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying financial statements and notes are prepared in accordance with accounting principles generally accepted in the United States of America, or U.S. GAAP, and are prepared on the basis that the Company will continue as a going concern (see Note 2). The accompanying financial statements and notes do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern.

On September 27, 2016, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s amended and restated certificate of incorporation to effect a one-for-three reverse stock split of the Company’s outstanding common stock, and to increase the authorized number of shares of the Company’s common stock from 40,000,000 to 150,000,000 shares. The one-for-three reverse stock split was effected on September 29, 2016. As such, all references to share and per share amounts in these financial statements and accompanying notes have been retroactively restated to reflect the one-for-three reverse stock split, except for the authorized number of shares of the Company’s common stock of 150,000,000 shares, which was not affected by the one-for-three reverse stock split.

Going Concern

The Company assesses and determines its ability to continue as a going concern in accordance with the provisions of ASC Topic 205-40, Presentation of Financial Statements-Going Concern, which requires the Company to evaluate whether there are conditions or events that raise substantial doubt about its ability to continue as a going concern within one year after the date that its annual and interim financial statements are issued (see Note 2). Certain additional financial statement disclosures are required if such conditions or events are identified. If and when an entity’s liquidation becomes imminent, financial statements should be prepared under the liquidation basis of accounting. Determining the extent, if any, to which conditions or events raise substantial doubt about the Company’s ability to continue as a going concern, or the extent to which mitigating plans sufficiently alleviate any such substantial doubt, as well as whether or not liquidation is imminent, requires significant judgment by management.

Use of Estimates

The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, management evaluates these estimates and judgments, including those related to accounts receivable, inventories, long-lived assets, income taxes, revenues, stock-based compensation, and the determination of the Company’s ability to continue as a going concern. The Company bases its estimates on various assumptions that it believes are reasonable under the circumstances. Actual results may differ from these estimates under different assumptions or conditions.

Revenue Recognition and Accounts Receivable

The Company’s commercial revenues are generated from diagnostic services provided as delivered to physicians and billed to third-party insurance payers such as managed care organizations, Medicare and Medicaid and patients for any deductibles, coinsurance or copayments that may be due. Through December 31, 2017, the Company recognized revenue in accordance with the provision of Accounting Standards Codification, or ASC, 954-605, Health Care Entities-Revenue Recognition, which required that four basic criteria must be met prior to recognition of revenue: (1) persuasive evidence of an arrangement existed; (2) delivery had occurred and title and the risks and rewards of ownership had been transferred to the client or services had been rendered; (3) the price was fixed or determinable; and (4) collectability was reasonably assured. Commencing on March 31, 2017, the Company recognizes commercial revenue related to billings for assays delivered and billed to Medicare and other third-party payers on an accrual basis when amounts that will ultimately be realized can be estimated upon delivery, whereby prior to March 31, 2017, the Company recognized revenues for its commercial diagnostic services on a cash basis as collected because the amounts ultimately expected to be received could not be estimated upon delivery due to insufficient collection history experience. Commencing on January 1, 2018, the Company recognizes revenue in accordance with ASC 606, Revenue from Contracts with Customers, which requires that an entity recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services.

The Company bills third-party payers on a fee-for-service basis at the Company’s list price and third-party commercial revenue is recorded net of contractual discounts, payer-specific allowances and other reserves. The Company’s development services revenues are supported by contractual agreements and generated from assay development services provided to entities, as well as certain other diagnostic services provided to physicians. Diagnostic services are completed upon the delivery of assay results to the prescribing physician, at which time the Company bills for the service and revenue is recognized.

The Company’s gross commercial revenues billed, and corresponding gross accounts receivable are subject to estimated deductions for such allowances and reserves to arrive at reported net revenues, which relate to differences between amounts billed and corresponding amounts estimated to be subsequently collected. These third-party payer discounts and sales allowances are estimated based on a number of assumptions and factors, including historical payment trends, seasonality associated with the annual reset of patient deductible limits on January 1 of each year, and current and estimated future payments. Specifically, the Company maintains four such reserves: the reserve for contractual discounts, the reserve for aged non-patient receivables, the reserve for estimated patient receivables, and the reserve for other payer-specific sales allowances. The reserve for contractual discounts relates to discounts to gross amounts billed to Medicare and contracted third-party payers to arrive at the deemed “allowed expense” amount covered by that payer. The Company’s contracted third-party commercial sales are recorded using an actual or contracted fee schedule at the time of delivery, while estimated fee schedules are maintained for each non-contracted payer separately as part of other payer-specific sales allowances. Contractual discounts are recorded at the transaction level at the time of delivery based on a fee schedule that is maintained for each contracted third-party payer. The Company periodically adjusts fee schedules for both contracted and non-contracted third-party payers based upon historical payment trends. The reserve for aged non-patient receivables reduces gross amounts billed to non-contracted third-party payers for amounts estimated to be collected according to the age of the outstanding balance. The reserve for estimated patient receivables reduces gross amounts billed to third-party payers for amounts estimated to be collected directly from individual patients, such as copayments, deductibles, or amounts otherwise designated as patient responsibility. The reserve for other payer-specific sales allowances relates to the amounts billed to non-contracted third-party payers that are estimated to not be covered by that specific payer’s coverage policies, as well as estimated necessary adjustments to gross amounts billed based on historical collection experience for a particular third-party payer unrelated to the age of outstanding balances. Collection periods for billings on commercial revenues range from less than 30 days to several months, depending on the contracted or non-contracted nature of the payer, among other things.

The estimates of amounts that will ultimately be realized from commercial diagnostic services for non-contracted payers require significant judgment by management. Patients do not enter into direct agreements with the Company that commit them to pay any portion of the cost of the tests in the event that they have not met their annual deductible limit under their insurance policy, if any, or if their insurance otherwise declines to reimburse the Company. Adjustments to the estimated payment amounts are recorded at the time of final collection and settlement of each transaction as an adjustment to commercial revenue. Consideration associated with non-contracted commercial revenues is considered variable and constrained until fully adjudicated, with net revenues recorded to the extent that it is probable that a significant reversal will not occur. The estimation process used to determine third-party payer discounts and sales allowance has been applied on a consistent basis since March 31, 2017, and no significant subsequent adjustments have been necessary to increase or decrease these discounts and allowances as a result of changes in underlying estimates.

The composition of the Company’s gross and net revenues recognized during the years ended December 31, 2016 and 2017 is as follows:


	For the year ended December 31,
	2016		2017
Commercial revenues recognized upon delivery	$	—	$	15,685,069
Development services revenues recognized upon delivery		240,056		272,350
Commercial revenues recognized upon cash collection		2,983,040		1,225,976

Total gross revenues		3,223,096		17,183,395
Provisions for contractual discounts		—		(5,805,787	)
Provisions for aged non-patient receivables		—		(735,709	)
Provisions for estimated patient receivables		—		(169,479	)
Provisions for other payer-specific sales allowances		—		(5,403,757	)

Net revenues	$	3,223,096	$	5,068,663

During the year ended December 31, 2017, the Company recorded approximately $843,000 in nonrecurring net revenue as a result of recognizing revenue on an accrual basis commencing on March 31, 2017 associated with cases delivered on or prior to December 31, 2016, representing a corresponding decrease in net loss per common share of $0.90. The incremental net revenue as a result of recognizing revenue on an accrual basis commencing on March 31, 2017, or the total amount of net revenue recorded in excess of the amount of commercial cash collections, was approximately $1,139,000 during the year ended December 31, 2017, representing a corresponding decrease in net loss per common share of $1.20.

A summary of activity in the Company’s gross and net accounts receivable balances, as well as corresponding reserves, during the year ended December 31, 2017 is as follows:


	Balance at		Amounts			Settlements			Balance at
	December 31,		Recognized			Upon			December 31,
	2016		Upon Delivery			Adjudication			2017
Accounts receivable, gross	$	128,969	$	15,957,419		$	(9,149,325	)	$	6,937,063
Reserve for contractual discounts		—		(5,805,787	)		3,830,938			(1,974,849	)
Reserve for aged non-patient receivables		—		(735,709	)		283,621			(452,088	)
Reserve for estimated patient receivables		—		(169,479	)		81,359			(88,120	)
Reserve for other payer-specific sales allowances		—		(5,403,757	)		2,175,177			(3,228,580	)

Accounts receivable, net	$	128,969	$	3,842,687		$	(2,778,230	)	$	1,193,426

Cash

The Company places its cash with reputable financial institutions that are insured by the Federal Deposit Insurance Corporation, or FDIC. At times, deposits held may exceed the amount of insurance provided by the FDIC. The Company has not experienced any losses in its cash and believes they are not exposed to any significant credit risk.

Fair Value Measurement

The Company uses a three-tier fair value hierarchy to prioritize the inputs used in the Company’s fair value measurements. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets for identical assets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. The Company believes the carrying amount of cash, accounts receivable, accounts payable and accrued expenses approximate their estimated fair values due to the short-term maturities of these financial instruments. See Note 5 for further details about the inputs and assumptions used to determine fair value measurements.

Concentration of Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of temporary cash investments.

Concentrations of credit risk with respect to revenues are primarily limited to geographies to which the Company provides a significant volume of its services, and to specific third-party payers of the Company’s services such as Medicare, insurance companies, and other third-party payers. The Company’s client base consists of a large number of geographically dispersed clients diversified across various customer types.

The Company’s third-party payers that represent more than 10% of total net revenues in any period presented, as well as their related net revenue amount as a percentage of total net revenues, during the years ended December 31, 2016 and 2017 were as follows:


	For the year ended December 31,
	2016			2017
Medicare and Medicare Advantage		40	%		39	%
Blue Cross Blue Shield		11	%		19	%
United Healthcare		19	%		12	%

The Company’s third-party payers that represent more than 10% of total net accounts receivable, and their related net accounts receivable balance as a percentage of total net accounts receivable, at December 31, 2017 were as follows:


Blue Cross Blue Shield	27	%
Medicare and Medicare Advantage	21	%
United Healthcare	15	%

The Company operates in one reportable business segment and historically has derived most revenues only from within the United States.

Certain components used in the Company’s current or planned products are currently sourced from one supplier, for which alternative suppliers exist but the Company has not validated the product(s) of such alternative supplier(s), and substitutes for these components may not be obtained easily or may require substantial design or manufacturing modifications.

Inventories

Inventories are valued at the lower of cost or net realizable value. Cost is determined by the average cost method. The Company records adjustments to its inventory for estimated obsolescence or diminution in net realizable value equal to the difference between the cost of the inventory and the estimated net realizable value. At the point of loss recognition, a new cost basis for that inventory is established, and subsequent changes in facts and circumstances do not result in the restoration or increase in that newly established cost basis. In addition, the Company records a liability for firm, non-cancelable, and unconditional purchase commitments with contract manufacturers and suppliers for quantities in excess of the Company’s future demand forecasts consistent with its valuation of excess and obsolete inventory.

Fixed Assets

Fixed assets consist of machinery and equipment, furniture and fixtures, computer equipment and software, leasehold improvements, financed equipment and construction in-process. Fixed assets are stated at cost less accumulated depreciation and amortization. Additions, improvements, and major renewals are capitalized. Maintenance, repairs, and minor renewals are expensed as incurred. Depreciation and amortization are recorded using the straight-line method over the estimated useful lives of the assets, which range from three to seven years. Leasehold improvements are amortized over the life of the lease or the asset, whichever is shorter. Depreciation and amortization expense for the years ended December 31, 2016 and 2017 was approximately $322,000 and $576,000, respectively.

Upon sale or disposal of fixed assets, the accounts are relieved of the cost and the related accumulated depreciation or amortization with any gain or loss recorded to the statement of operations and comprehensive loss.

Fixed assets are reviewed for impairment whenever changes in circumstances indicate that the carrying amount of an asset may not be recoverable. These computations utilize judgments and assumptions inherent in the estimates of future cash flows to determine recoverability of these assets. If the assumptions about these assets were to change as a result of events or circumstances, the Company may be required to record an impairment loss.

Stock-based Compensation

The Company measures and recognizes compensation expense for all stock-based awards made to employees and directors based on their grant date fair values. The Company estimates the fair value of stock option awards on the date of grant using the Black-Scholes option pricing model, while the fair value of restricted stock unit awards, or RSUs, is determined by the Company’s stock price on the date of grant. The value of the portion of the award that is ultimately expected to vest is recognized as expense over the requisite service periods using the straight-line method. Upon adoption of Accounting Standards Update 2016-09, Compensation—Stock Compensation on January 1, 2017, the Company estimates forfeitures at the time of grant and revises these estimates in subsequent periods if actual forfeitures differ from those estimates (see Note 10).

The Company determines the fair value of the stock-based compensation awards granted as either the fair value of the consideration received, or the fair value of the equity instruments issued, whichever is more reliably measurable. All issuances of equity instruments issued to non-employees as consideration for goods or services received by the Company are accounted for based on the fair value of the equity instruments issued. These awards are recorded in expense and additional paid-in capital in shareholders’ equity over the applicable service periods based on the fair value of the options at the end of each period.

Calculating the fair value of stock-based awards requires the input of highly subjective assumptions into the Black-Scholes valuation model. Stock-based compensation expense is calculated using the Company’s best estimates, which involves inherent uncertainties, and the application of management’s judgment. Significant estimates include the expected life of the stock option, stock price volatility, risk-free interest rate and forfeiture rate.

Research and Development

Research and development costs are expensed as incurred. The amounts expensed in the years ended December 31, 2016 and 2017 were approximately $2,713,000 and $3,365,000, respectively, which includes salaries of research and development personnel.

Income Taxes

The Company provides for income taxes utilizing the liability method. Under the liability method, current income tax expense or benefit is the amount of income taxes expected to be payable or refundable for the current year. A deferred income tax asset or liability is computed for the expected future impact of differences between the financial reporting and tax bases of assets and liabilities and for the expected future tax benefit to be derived from tax credits. Tax rate changes are reflected in the computation of the income tax provision during the period such changes are enacted.

Deferred tax assets are reduced by a valuation allowance when, in management’s opinion, it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income, and tax planning strategies in making this assessment. The Company’s valuation allowance is based on available evidence, including its current year operating loss, evaluation of positive and negative evidence with respect to certain specific deferred tax assets including evaluation sources of future taxable income to support the realization of the deferred tax assets. The Company has established a full valuation allowance on the deferred tax assets as of December 31, 2016 and 2017, and therefore has not recognized any income tax benefit or expense in the periods presented.

A tax benefit from uncertain tax positions may be recognized by the Company when it is more-likely-than-not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on the technical merits of the position. Income tax positions must meet a more-likely-than-not recognition threshold to be recognized.

The Company recognizes interest and/or penalties related to income tax matters in income tax expense. There is no accrual for interest or penalties for income taxes on the balance sheets at December 31, 2016 and 2017, and the Company has not recognized interest and/or penalties in the statements of operations and comprehensive loss for the years ended December 31, 2016 and 2017.

Recent Accounting Pronouncements

In May 2014, and as subsequently updated and amended from time to time, the Financial Accounting Standards Board, or FASB, issued authoritative guidance that requires entities to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. This guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period, and may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. Earlier application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. The Company adopted the new standard for the fiscal year beginning January 1, 2018 using the modified retrospective application method. The Company has substantially completed its assessment of the new standard and the Company believes that there will not be a material impact on its financial statements or disclosures.

In July 2015, the FASB issued authoritative guidance requiring entities that do not measure inventory using the retail inventory method or on a last-in, first-out basis to record inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. This guidance is effective on a prospective basis for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company adopted this guidance for the reporting period beginning January 1, 2017, which did not have a material impact on its financial statements or disclosures.

In January 2016, the FASB issued authoritative guidance requiring, among other things, that certain equity investments be measured at fair value with changes in fair value recognized in net income, that financial assets and financial liabilities be presented separately by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements, that the prior requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet be eliminated, and that a reporting organization is to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. This guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. Early adoption of the instrument-specific credit risk amendment is permitted. The Company adopted this guidance for the fiscal year beginning on January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In February 2016, the FASB issued authoritative guidance requiring, among other things, that entities recognize the assets and liabilities arising from leases on the balance sheet under revised criteria, while the classification criteria for distinguishing between finance leases and operating leases are substantially similar to the classification criteria in the previous leases guidance. In transition, lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company anticipates that the adoption of this guidance will materially affect its statement of financial position and will require changes to its processes. The Company expects to adopt this guidance for the reporting period beginning on January 1, 2019 and has not yet made any decision on the method of adoption with respect to the optional practical expedients but expects to during 2018.

In March 2016, the FASB issued authoritative guidance clarifying that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument does not necessarily require de-designation of that hedging relationship, provided that all other applicable hedge accounting criteria continue to be met. This guidance is effective on either a prospective basis or modified retrospective basis for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. The Company adopted this guidance for the reporting period beginning January 1, 2017, which did not have a material impact on its financial statements or disclosures.

In March 2016, the FASB issued authoritative guidance requiring entities to assess whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts, and clarifies what steps are required when assessing whether the economic characteristics and risks of call (put) options are clearly and closely related to the economic characteristics and risks of their debt hosts. This guidance is effective on a modified retrospective basis for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. Early adoption is permitted. The Company adopted this guidance for the reporting period beginning January 1, 2017, which did not have a material impact on its financial statements or disclosures.

In March 2016, the FASB issued authoritative guidance simplifying the accounting for stock compensation. This guidance, among other things, amends existing accounting and classification requirements primarily around income taxes, forfeitures, and cash payments associated with share-based payment awards to employees. This guidance is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early adoption is permitted. The Company adopted this guidance for the reporting period beginning January 1, 2017, which did not have a material impact on its financial statements or disclosures.

In August 2016, the FASB issued authoritative guidance clarifying the classification of certain cash receipts and cash payments in the statement of cash flows. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, on a retrospective transition method to each period presented. Early adoption is permitted. The Company adopted this guidance for the reporting period beginning January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In January 2017, the FASB issued authoritative guidance clarifying the definition of a business when evaluating transactions involving acquisitions or disposals of assets or businesses. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Certain applications of this guidance are permitted for early adoption. The Company adopted this guidance for the reporting period beginning January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In January 2017, the FASB issued authoritative guidance eliminating the “Step 2” requirement for an entity to determine the fair value of its assets and liabilities for goodwill impairment testing in the same manner that would be required for those assumed in a business combination. Instead, the amended guidance allows an entity to perform goodwill impairment testing by comparing the fair value of a reporting unit with its carrying amount. This guidance is effective for any goodwill impairment tests in fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. The Company currently intends to adopt this guidance for the fiscal year beginning January 1, 2020, and does not anticipate that the adoption of this guidance will have a material impact on its financial statements or disclosures because the Company does not currently have any recorded goodwill.

In February 2017, the FASB issued authoritative guidance clarifying the definition of the term “in substance nonfinancial asset” when accounting for transfers of financial and nonfinancial assets, and other matters concerning the transfer, sale and partial sale of nonfinancial assets to both consolidated entities and non-consolidated counterparties. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within that reporting period. Early adoption is permitted. The Company adopted this guidance for the reporting period beginning January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In March 2017, the FASB issued authoritative guidance shortening the amortization period to the earliest call date for certain purchased callable debt securities held at a premium. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company currently intends to adopt this guidance for the fiscal year beginning on January 1, 2019 and does not anticipate that the adoption of this guidance will have a material impact on its financial statements or disclosures because the Company does not currently hold any callable debt securities.

In May 2017, the FASB issued authoritative guidance clarifying what modifications to a share-based payment award may be considered substantive, and therefore requiring the application of modification accounting. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The Company adopted this guidance for the reporting period beginning January 1, 2018, which did not have a material impact on its financial statements or disclosures.

Supplier Financings	12 Months Ended
Supplier Financings	Dec. 31, 2017
Debt Disclosure [Abstract]
Supplier Financings	9. Supplier Financings In 2016 and 2017, the Company obtained third-party financing for certain business insurance premiums. The 2016 and 2017 financings bear interest rates ranging from 3.75% to 5.70% per annum, and all financings are due within one year. The balances due under these annual financing arrangements were approximately $76,000 and $61,000 as of December 31, 2016 and 2017, respectively.

401(k) Plan	12 Months Ended
401(k) Plan	Dec. 31, 2017
Postemployment Benefits [Abstract]
401(k) Plan	13. 401(k) Plan The Company sponsors a 401(k) savings plan for all eligible employees. The Company may make discretionary matching contributions to the plan to be allocated to employee accounts based upon employee deferrals and compensation. During the years ended December 31, 2016 and 2017, the Company made zero and approximately $90,000, respectively, in matching contributions into the savings plan.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

14. Income Taxes

On December 22, 2017, the President of the United States signed into law new legislation, or the Act, that significantly revises the Internal Revenue Code of 1986, as amended, or the Code. The Act amends the Code to reduce tax rates and modify policies, credits, and deductions for individuals and businesses. For businesses, the Act reduces the corporate tax rate from a maximum of 35% to a flat 21% rate. The rate reduction is effective on January 1, 2018. As a result of the rate reduction, the Company has reduced the deferred tax asset balance as of December 31, 2017 by approximately $2.6 million. Due to the Company’s full valuation allowance position, the Company has also reduced the valuation allowance by the same amount. Due to uncertainties which currently exist in the interpretation of the provisions of the Act regarding Code Section 162(m), the Company has not evaluated the potential impacts of Code Section 162(m) as amended by the Act on its financial statements.

On December 22, 2017, Staff Accounting Bulletin No. 118, or SAB 118, was issued to address the application of U.S. GAAP when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. In accordance with SAB 118, the Company has determined that there is no deferred tax benefit or expense with respect to the remeasurement of certain deferred tax assets and liabilities due to the full valuation allowance against net deferred tax assets. Additional analysis of the law and the impact to the Company will be performed and any impact will be recorded in the respective quarter in 2018.

For the years ended December 31, 2016 and 2017, the provision for income taxes was calculated as follows:


	For the year ended December 31,
	2016		2017
Current:
Federal	$	—	$	—
State		2,053		7,624

Total		2,053		7,624
Deferred
Federal		—		—
State		—		—

Total		—		—

Provision for income tax	$	2,053	$	7,624

The following table reconciles income taxes computed at the federal statutory rate and the Company’s provision for income taxes:


	For the year ended December 31,
	2016			2017
Income tax at statutory rate	$	(6,255,072	)	$	(7,346,079	)
Change in federal tax rate		—			2,621,803
State liability		(260,835	)		(411,853	)
Permanent items		67,151			214,313
Stock compensation		157,250			72,696
Nondeductible interest		21,548			15,568
Expiration of net operating losses		—			922,307
Research and development credit		(170,950	)		(200,379	)
State rate change		44,421			(18,026	)
Estimated section 382 limitation		9,256,295			1,491,942
Return to provision		—			365,263
Other		96,406			488,264
Valuation allowance		(2,954,161	)		1,791,805

Provision for income tax	$	2,053		$	7,624

Deferred income taxes are provided for temporary differences in recognizing certain income and expense items for financial and tax reporting purposes. The deferred tax assets consisted primarily of the income tax benefits from estimated net operating loss carryforwards, deferred rent, and estimated research and development credits. Valuation allowances have been recorded to fully offset deferred tax assets at December 31, 2016 and 2017, as it is more likely than not that the assets will not be utilized.

At December 31, 2017, the Company had estimated federal net operating loss carryforwards of approximately $13.6 million expiring beginning in 2035 and total estimated state net operating loss carryforwards of approximately $15.0 million expiring beginning in 2023. Additionally, at December 31, 2017, the Company had estimated research and development credits of approximately $5,000 and $3,395,000 for federal and California purposes, respectively. The estimated federal research and development tax credits will begin to expire in 2035. The California research and development tax credits do not expire.

For the years ended December 31, 2016 and 2017, the Company has evaluated the various tax positions reflected in its income tax returns for both federal and state jurisdictions, to determine if the Company has any uncertain tax positions on the historical tax returns. The Company recognizes the impact of an uncertain tax position on an income tax return at the largest amount that the relevant taxing authority is more-likely-than not to sustain upon audit. The Company does not recognize uncertain income tax positions if they have less than 50 percent likelihood of being sustained. Based on this assessment, the Company believes there are no tax positions for which a liability for unrecognized tax benefits should be recorded as of December 31, 2016 or 2017. The Company is subject to U.S. federal income tax as well as income tax in multiple state jurisdictions. With few exceptions, the Company is no longer subject to U.S. federal income tax examinations for 2014 and before, state and local income tax examinations 2013 and before. However, to the extent allowed by law, the tax authorities may have the right to examine prior periods where net operating losses were generated and carried forward and make adjustments up to the amount of the net operating loss carry forward amount. The Company’s policy is to recognize interest and penalties related to income tax matters in income tax expense. Due to the existence of the valuation allowance, future changes in unrecognized tax benefits will not impact the Company’s effective tax rate. The Company is currently not under examination by any taxing authorities and does not believe its unrecognized tax benefits will significantly change in the next twelve months.

The tax effects of carryforwards and other temporary differences that give rise to deferred tax assets consist of the following:


	For the year ended December 31,
	2016			2017
Estimated net operating loss carryforward	$	2,218,618		$	3,355,180
Estimated research and development credits		2,244,047			2,686,666
Accruals and other		2,273,838			2,560,417
Deferred rent		164,821			90,866

		6,901,324			8,693,129
Less valuation allowance		(6,901,324	)		(8,693,129	)

Net deferred tax assets	$	—		$	—

Utilization of the estimated domestic net operating loss and research and development credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that may have occurred or that could occur in the future, as required by Section 382 and 383 of the Code, as well as similar state provisions. These ownership changes may limit the amount of estimated net operating loss and research and development credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an “ownership change” as defined by Section 382 of the Code results from a transaction or series of transactions over a three-year period resulting in an ownership change of more than 50 percentage points of the outstanding stock of a company by certain stockholders. Since the Company’s formation, the Company has raised capital through the issuance of capital stock on several occasions which on its own or combined with the purchasing stockholders’ subsequent disposition of those shares, likely resulted in such an ownership change, or could result in an ownership change in the future.

Upon the occurrence of an ownership change under Section 382 of the Code as outlined above, utilization of the estimated net operating loss and research and development credit carryforwards are subject to an annual limitation under Section 382, which is determined by first multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term, tax-exempt rate, which could be subject to additional adjustments, as required. Any limitation may result in expiration of a portion of the estimated net operating loss or research and development credit carryforwards before utilization. The Company has not yet completed an analysis to determine whether an ownership change has occurred, however, the Company believes ownership changes likely occurred in each year from 2015 through 2018. As a result, the Company has estimated that the use of its net operating loss is limited and has disclosed in the table above only the amounts it estimates could be used in the future, which remain fully offset by a valuation allowance to reduce the net asset to zero.

Selected Quarterly Financial Data

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data (Unaudited)

17. Selected Quarterly Financial Data (Unaudited)

The following is selected quarterly financial data as of and for the periods ending:


	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
December 31, 2016
Balance sheet data:
Cash	$	4,572,750		$	3,751,570		$	678,855		$	4,609,332
Total assets		6,780,830			6,303,153			3,282,549			7,578,326
Total non-current liabilities		3,132,372			3,134,593			2,793,258			2,526,113
Total shareholders’ equity		(489,231	)		(419,402	)		(4,556,158	)		658,661
Statement of operations and comprehensive loss data:
Net revenues	$	221,369		$	662,860		$	1,047,280		$	1,291,587
Cost of revenues		1,474,790			1,669,571			1,876,288			1,899,462
Research and development expenses		728,076			716,279			600,613			668,399
General and administrative expenses		1,487,224			1,517,664			1,918,543			1,636,994
Sales and marketing expenses		1,304,899			1,291,709			1,278,455			1,179,167
Loss from operations		(4,773,620	)		(4,532,363	)		(4,626,619	)		(4,092,435	)
Net loss	$	(4,875,198	)	$	(4,594,174	)	$	(4,743,076	)	$	(4,186,874	)
Net loss per common share:¹
Basic	$	(22.27	)	$	(17.89	)	$	(16.99	)	$	(8.04	)

Diluted	$	(22.27	)	$	(17.89	)	$	(16.99	)	$	(8.04	)

Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic		218,900			256,742			279,023			520,668

Diluted		218,900			256,742			279,023			520,668

¹	Basic and diluted net loss per common share are computed independently for each of the components and quarters presented. Therefore, the sum of quarterly basic and diluted per share information may not equal annual basic and diluted net loss per common share.


	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
December 31, 2017
Balance sheet data:
Cash	$	14,042,388		$	10,000,155		$	5,879,025		$	2,146,611
Total assets		17,933,413			14,653,193			11,120,215			7,378,906
Total non-current liabilities		2,062,544			1,561,520			1,255,939			1,421,527
Total shareholders’ equity		10,418,069			7,342,257			4,026,079			1,296,034
Statement of operations and comprehensive loss data:
Net revenues	$	1,683,065		$	1,278,961		$	1,111,411		$	995,226
Cost of revenues		2,129,454			2,368,705			2,487,054			2,359,909
Research and development expenses		757,258			841,991			856,698			908,800
General and administrative expenses		1,906,635			1,798,026			1,834,771			1,650,097
Sales and marketing expenses		1,278,311			1,746,867			1,675,852			1,642,941
Loss from operations		(4,388,593	)		(5,476,628	)		(5,742,964	)		(5,566,521	)
Net loss	$	(4,432,707	)	$	(5,693,151	)	$	(5,821,306	)	$	(5,666,573	)
Net loss per common share:¹
Basic	$	(6.27	)	$	(6.32	)	$	(5.85	)	$	(5.36	)

Diluted	$	(6.27	)	$	(6.32	)	$	(5.85	)	$	(5.36	)

Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic		707,389			901,007			995,254			1,058,055

Diluted		707,389			901,007			995,254			1,058,055

¹	Basic and diluted net loss per common share are computed independently for each of the components and quarters presented. Therefore, the sum of quarterly basic and diluted per share information may not equal annual basic and diluted net loss per common share.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2017
Subsequent Events [Abstract]
Event (Unaudited) Subsequent to the Date of the Independent Auditor's Report	18. Subsequent Events On January 26, 2018, the Company executed a lease agreement with a third-party lender to finance approximately $250,000 of planned fixed asset purchases. Under the terms of the lease agreement, upon lease commencement and repayment, which occurs once the Company has financed equipment purchases for the full amount available under the lease agreement, the Company is required to make 22 payments of $11,081 per month during the initial term of the agreement, subject to adjustment in the event of an increase in three-year Treasury note rates prior to lease commencement and repayment. Until lease commencement and repayment, the Company is required to pay pro-rated equipment rental charges of any equipment financed under this lease. The Company expects lease commencement and repayment to occur by June 30, 2018. Through the date that these financial statements were available to be issued, approximately $78,000 of equipment purchases had been financed under this lease agreement. On January 30, 2018, the Company received net cash proceeds of approximately $13.3 million as a result of the closing of a follow-on public offering of 1,095,153 shares of its common stock and warrants to purchase up to an aggregate of 1,095,153 shares of its common stock at a combined offering price of $13.50 per unit. All warrants sold in this offering have an exercise price of $15.00 per share, subject to down round adjustment, are exercisable immediately and expire five years from the date of issuance. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering. On July 6, 2018, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s Certificate of Amendment of Certificate of Incorporation to effect a one-for-thirty reverse stock split of the Company’s outstanding common stock. As such, all references to share and per share amounts in these financial statements and accompanying notes have been retroactively restated to reflect the one-for-thirty reverse stock split, except for the authorized number of shares of the Company’s common stock of 150,000,000 shares, which was not affected by the one-for-thirty reverse stock split.

Event (Unaudited) Subsequent to the Date of the Independent Auditor's Report	12 Months Ended
	Dec. 31, 2017
Event (Unaudited) Subsequent to the Date of the Independent Auditor's Report	18. Subsequent Events On January 26, 2018, the Company executed a lease agreement with a third-party lender to finance approximately $250,000 of planned fixed asset purchases. Under the terms of the lease agreement, upon lease commencement and repayment, which occurs once the Company has financed equipment purchases for the full amount available under the lease agreement, the Company is required to make 22 payments of $11,081 per month during the initial term of the agreement, subject to adjustment in the event of an increase in three-year Treasury note rates prior to lease commencement and repayment. Until lease commencement and repayment, the Company is required to pay pro-rated equipment rental charges of any equipment financed under this lease. The Company expects lease commencement and repayment to occur by June 30, 2018. Through the date that these financial statements were available to be issued, approximately $78,000 of equipment purchases had been financed under this lease agreement. On January 30, 2018, the Company received net cash proceeds of approximately $13.3 million as a result of the closing of a follow-on public offering of 1,095,153 shares of its common stock and warrants to purchase up to an aggregate of 1,095,153 shares of its common stock at a combined offering price of $13.50 per unit. All warrants sold in this offering have an exercise price of $15.00 per share, subject to down round adjustment, are exercisable immediately and expire five years from the date of issuance. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering. On July 6, 2018, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s Certificate of Amendment of Certificate of Incorporation to effect a one-for-thirty reverse stock split of the Company’s outstanding common stock. As such, all references to share and per share amounts in these financial statements and accompanying notes have been retroactively restated to reflect the one-for-thirty reverse stock split, except for the authorized number of shares of the Company’s common stock of 150,000,000 shares, which was not affected by the one-for-thirty reverse stock split.
Unaudited [Member]
Event (Unaudited) Subsequent to the Date of the Independent Auditor's Report	19. Event (Unaudited) Subsequent to the Date of the Independent Auditor’s Report On August 13, 2018, the Company received net cash proceeds of approximately $10.2 million from closing a rights offering pursuant to its effective registration statement on Form S-1, selling an aggregate of 11,587 units consisting of an aggregate of 11,587 shares of Series A Preferred Stock and 2,549,140 warrants. The warrants are exercisable for one share of our common stock at an exercise price of $4.53 per share, an aggregate estimated grant date fair value of $8.4 million and expire five years from the date of issuance. The Series A Preferred Stock is convertible into the Company’s common stock at a conversion price of $4.53, includes a right to participate in subsequent right offerings and has a right to participate in stock dividends and splits, if any. Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering. On September 20, 2018, the Company completed an offering of 642,438 shares of the Company’s common stock and pre-funded warrants to purchase up to an aggregate of 120,000 shares of its common stock. The shares were sold at a purchase price of $3.285 per share and the pre-funded warrants were sold at a purchase price of $3.275 per pre-funded warrant which represents the per share purchase price for the shares less the $0.01 per share exercise price for each such pre-funded warrant. The net proceeds to the Company from this offering were approximately $2.2 million, after deducting expenses related to the offering including dealer-manager fees and expenses, and excluding any proceeds received upon exercise of any warrants. In addition, in a concurrent private placement, the Company issued to purchasers a warrant to purchase one share of the Company’s common stock for each share and pre-funded warrant purchased for cash in the offering. All warrants issued in this offering have an exercise price of $3.16 per share, are exercisable upon the six-month anniversary of issuance and expire five years from such date. On January 18, 2019, we entered into a Securities Purchase Agreement with certain purchasers pursuant to which we sold to such purchasers, in a registered direct offering, an aggregate of 990,000 shares of common stock at a negotiated purchase price of $2.25 per share for aggregate net proceeds to us of approximately $2.0 million.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

The Company and Business Activities

The Company and Business Activities

The Company was founded in California in May 1997 and is an early stage molecular oncology diagnostics company that develops and commercializes proprietary circulating tumor cell, or CTC, and circulating tumor DNA, or ctDNA, assays utilizing a standard blood sample, or liquid biopsy. The Company’s current and planned assays are intended to provide information to aid healthcare providers to identify specific oncogenic alterations that may qualify a subset of cancer patients for targeted therapy at diagnosis, progression or for monitoring in order to identify specific resistance mechanisms. Sometimes traditional procedures, such as surgical tissue biopsies, result in tumor tissue that is insufficient and/or unable to provide the molecular subtype information necessary for clinical decisions. The Company’s assays, performed on blood, have the potential to provide more contemporaneous information on the characteristics of a patient’s disease when compared with tissue biopsy and radiographic imaging. Additionally, commencing in October 2017, the Company’s pathology partnership program, Empower TC, provides the unique ability for pathologists to participate in the interpretation of liquid biopsy results and is available to pathology practices and hospital systems throughout the United States. Further, the Company’s proprietary blood collection tubes, which allow for the intact transport of liquid biopsy samples for research use only from regions around the world, are anticipated to be sold to laboratory supply distributors commencing in 2018.

In July 2013, the Company effected a reincorporation to Delaware by merging itself with and into Biocept, Inc., a Delaware corporation, which had been formed to be and was a wholly-owned subsidiary of the Company since July 23, 2013.

Basis of Presentation

Certain prior period balances have been reclassified to conform to the current period presentation.

Basis of Presentation

Going Concern

Going Concern

Use of Estimates

Use of Estimates

Revenue Recognition and Accounts Receivable

Contracts


	•		Approval of a contract is established via the order and accession, which are submitted by the patient’s physician.
	•		The Company is obligated to perform its diagnostic services upon receipt of a sample from a physician, and the patient and/or applicable payer are obligated to reimburse the Company for services rendered based on the patient’s insurance benefits.


	•		Payment terms are a function of a patient’s existing insurance benefits, including the impact of coverage decisions with CMS and applicable reimbursement contracts established between the Company and payers, unless the patient is a self-pay patient, whereby the Company bills the patient directly after the services are provided.
	•		Once the Company delivers a patient’s assay result to the ordering physician, the contract with a patient has commercial substance, as the Company is legally able to collect payment and bill an insurer and/or patient, regardless of payer contract status or patient insurance benefit status.


	•		Consideration associated with commercial revenues is considered variable and constrained until fully adjudicated, with net revenues recorded to the extent that it is probable that a significant reversal will not occur.

Performance Obligations

Transaction Price

Allocate Transaction Price

Point-in-time Recognition

Contract Balances

Practical Expedients

The Company does not adjust the transaction price for the effects of a significant financing component, as at contract inception, the Company expects the collection cycle to be one year or less.

The Company expenses sales commissions when incurred because the amortization period is one year or less, which are recorded within sales and marketing expenses.

Disaggregation of Revenue and Concentration of Risk

The composition of the Company’s net revenues recognized during the three and nine months ended September 30, 2017 and 2018, disaggregated by source and nature, are as follows:

	For the three months ended September 30,				For the nine months ended September 30,
	2017		2018		2017		2018
Net revenues from contracted payers*	$	422,136	$	325,097	$	1,655,287	$	1,019,857
Net revenues from non-contracted payers		621,881		373,018		2,206,414		1,211,309
Development services revenues		67,394		63,476		211,736		159,606
Total net revenues	$	1,111,411	$	761,591	$	4,073,437	$	2,390,772

*Includes Medicare and Medicare Advantage, as reimbursement amounts are fixed and miscellaneous income from CEE-Sure blood collection tubes.

	For the three months ended September 30,				For the nine months ended September 30,
	2017		2018		2017		2018
Net commercial revenues recognized upon delivery	$	941,783	$	698,115	$	2,703,424	$	2,231,166
Development services revenues recognized upon delivery		67,394		63,476		211,736		159,606
Commercial revenues recognized upon cash collection		102,234		—		1,158,277		—
Total net revenues	$	1,111,411	$	761,591	$	4,073,437	$	2,390,772

Revenue Recognition and Accounts Receivable

The composition of the Company’s gross and net revenues recognized during the years ended December 31, 2016 and 2017 is as follows:


	For the year ended December 31,
	2016		2017
Commercial revenues recognized upon delivery	$	—	$	15,685,069
Development services revenues recognized upon delivery		240,056		272,350
Commercial revenues recognized upon cash collection		2,983,040		1,225,976

Total gross revenues		3,223,096		17,183,395
Provisions for contractual discounts		—		(5,805,787	)
Provisions for aged non-patient receivables		—		(735,709	)
Provisions for estimated patient receivables		—		(169,479	)
Provisions for other payer-specific sales allowances		—		(5,403,757	)

Net revenues	$	3,223,096	$	5,068,663

A summary of activity in the Company’s gross and net accounts receivable balances, as well as corresponding reserves, during the year ended December 31, 2017 is as follows:


	Balance at		Amounts			Settlements			Balance at
	December 31,		Recognized			Upon			December 31,
	2016		Upon Delivery			Adjudication			2017
Accounts receivable, gross	$	128,969	$	15,957,419		$	(9,149,325	)	$	6,937,063
Reserve for contractual discounts		—		(5,805,787	)		3,830,938			(1,974,849	)
Reserve for aged non-patient receivables		—		(735,709	)		283,621			(452,088	)
Reserve for estimated patient receivables		—		(169,479	)		81,359			(88,120	)
Reserve for other payer-specific sales allowances		—		(5,403,757	)		2,175,177			(3,228,580	)

Accounts receivable, net	$	128,969	$	3,842,687		$	(2,778,230	)	$	1,193,426

Cash

Cash

Fair Value Measurement

Fair Value Measurement

Concentration of Risk

	For the three months ended September 30,						For the nine months ended September 30,
	2017			2018			2017			2018
Medicare and Medicare Advantage		45	%		40	%		41	%		39	%
Blue Cross Blue Shield		16	%		9	%		17	%		14	%
United Healthcare		14	%		6	%		12	%		15	%

	December 31, 2017			September 30, 2018
Blue Cross Blue Shield		27	%		22	%
Medicare and Medicare Advantage		21	%		18	%
United Healthcare		15	%		11	%

Concentration of Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of temporary cash investments.

Concentrations of credit risk with respect to revenues are primarily limited to geographies to which the Company provides a significant volume of its services, and to specific third-party payers of the Company’s services such as Medicare, insurance companies, and other third-party payers. The Company’s client base consists of a large number of geographically dispersed clients diversified across various customer types.


	For the year ended December 31,
	2016			2017
Medicare and Medicare Advantage		40	%		39	%
Blue Cross Blue Shield		11	%		19	%
United Healthcare		19	%		12	%


Blue Cross Blue Shield	27	%
Medicare and Medicare Advantage	21	%
United Healthcare	15	%

The Company operates in one reportable business segment and historically has derived most revenues only from within the United States.

Inventories

Inventories

Fixed Assets

Fixed Assets

Stock-based Compensation

Stock-based Compensation

Research and Development

Research and Development

Income Taxes

Income Taxes

Recent Accounting Pronouncements

Recent Accounting Pronouncements

In May 2014, and as subsequently updated and amended from time to time, the Financial Accounting Standards Board, or FASB, issued authoritative guidance that requires entities to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. This guidance is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period, and may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption. Earlier application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. The Company adopted the new standard for the fiscal year beginning January 1, 2018 using the modified retrospective application method. The Company has substantially completed its assessment of the new standard and the Company believes that there will not be a material impact on its financial statements or disclosures.

In January 2016, the FASB issued authoritative guidance requiring, among other things, that certain equity investments be measured at fair value with changes in fair value recognized in net income, that financial assets and financial liabilities be presented separately by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements, that the prior requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet be eliminated, and that a reporting organization is to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. This guidance is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. Early adoption of the instrument-specific credit risk amendment is permitted. The Company adopted this guidance for the fiscal year beginning on January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In February 2016, the FASB issued authoritative guidance requiring, among other things, that entities recognize the assets and liabilities arising from leases on the balance sheet under revised criteria, while the classification criteria for distinguishing between finance leases and operating leases are substantially similar to the classification criteria in the previous leases guidance. In transition, lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. This guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company anticipates that the adoption of this guidance will materially affect its statement of financial position and will require changes to its processes. The Company expects to adopt this guidance for the reporting period beginning on January 1, 2019 and has not yet made any decision on the method of adoption with respect to the optional practical expedients but expects to during 2018.

In August 2016, the FASB issued authoritative guidance clarifying the classification of certain cash receipts and cash payments in the statement of cash flows. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, on a retrospective transition method to each period presented. Early adoption is permitted. The Company adopted this guidance for the reporting period beginning January 1, 2018, which did not have a material impact on its financial statements or disclosures.

In January 2017, the FASB issued authoritative guidance clarifying the definition of a business when evaluating transactions involving acquisitions or disposals of assets or businesses. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Certain applications of this guidance are permitted for early adoption. The Company adopted this guidance for the reporting period beginning January 1, 2018, which did not have a material impact on its financial statements or disclosures.

Stock Options [Member]

Fair Value Measurement

Restricted Stock [Member]

Fair Value Measurement

The Company, Business Activities and Basis of Presentation (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Accounting Policies [Abstract]

Composition of Net Revenues Recognized Disaggregated by Source and Nature

The composition of the Company’s net revenues recognized during the three and nine months ended September 30, 2017 and 2018, disaggregated by source and nature, are as follows:

	For the three months ended September 30,				For the nine months ended September 30,
	2017		2018		2017		2018
Net revenues from contracted payers*	$	422,136	$	325,097	$	1,655,287	$	1,019,857
Net revenues from non-contracted payers		621,881		373,018		2,206,414		1,211,309
Development services revenues		67,394		63,476		211,736		159,606
Total net revenues	$	1,111,411	$	761,591	$	4,073,437	$	2,390,772

*Includes Medicare and Medicare Advantage, as reimbursement amounts are fixed and miscellaneous income from CEE-Sure blood collection tubes.

	For the three months ended September 30,				For the nine months ended September 30,
	2017		2018		2017		2018
Net commercial revenues recognized upon delivery	$	941,783	$	698,115	$	2,703,424	$	2,231,166
Development services revenues recognized upon delivery		67,394		63,476		211,736		159,606
Commercial revenues recognized upon cash collection		102,234		—		1,158,277		—
Total net revenues	$	1,111,411	$	761,591	$	4,073,437	$	2,390,772

Summary of Third-Party Payers That Represent More Than 10% of Total Net Revenues and Total Net Accounts Receivable and Their Related Percentage

	For the three months ended September 30,						For the nine months ended September 30,
	2017			2018			2017			2018
Medicare and Medicare Advantage		45	%		40	%		41	%		39	%
Blue Cross Blue Shield		16	%		9	%		17	%		14	%
United Healthcare		14	%		6	%		12	%		15	%

	December 31, 2017			September 30, 2018
Blue Cross Blue Shield		27	%		22	%
Medicare and Medicare Advantage		21	%		18	%
United Healthcare		15	%		11	%


	For the year ended December 31,
	2016			2017
Medicare and Medicare Advantage		40	%		39	%
Blue Cross Blue Shield		11	%		19	%
United Healthcare		19	%		12	%


Blue Cross Blue Shield	27	%
Medicare and Medicare Advantage	21	%
United Healthcare	15	%

Balance Sheet Details (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Fixed Assets and Accrued Liabilities

The following provides certain balance sheet details:

	December 31,			September 30,
	2017			2018
Fixed Assets
Machinery and equipment	$	2,841,388		$	2,810,226
Furniture and office equipment		147,976			157,391
Computer equipment and software		1,637,034			1,430,669
Leasehold improvements		553,529			570,174
Financed equipment		2,294,762			2,526,081
Construction in process		2,975			128,377
Total fixed assets, gross		7,477,664			7,622,918
Less accumulated depreciation and amortization		(4,354,097	)		(4,721,924	)
Total fixed assets, net	$	3,123,567		$	2,900,994
Accrued Liabilities
Accrued payroll		224,813			387,162
Accrued vacation		474,953			470,473
Accrued bonuses		375,000			804,281
Accrued sales commissions		104,509			42,168
Current portion of deferred rent		116,681			147,771
Accrued other		129,805			102,115
Total accrued liabilities	$	1,425,761		$	1,953,970

The following provides certain balance sheet details:


	December 31, 2016			December 31, 2017
Fixed Assets
Machinery and equipment	$	2,728,468		$	2,841,388
Furniture and office equipment		143,726			147,976
Computer equipment and software		620,582			1,637,034
Leasehold improvements		517,968			553,529
Financed equipment		1,559,690			2,294,762
Construction in process		169,896			2,975

		5,740,330			7,477,664
Less accumulated depreciation and amortization		(3,933,999	)		(4,354,097	)

Total fixed assets, net	$	1,806,331		$	3,123,567

Accrued Liabilities
Accrued interest	$	20,776		$	326,602
Accrued payroll		168,727			224,813
Accrued vacation		364,953			474,953
Accrued bonuses		422,868			375,000
Accrued sales commissions		77,844			104,509
Current portion of deferred rent		67,085			116,681
Accrued other		37,783			129,805

Total accrued liabilities	$	1,160,036		$	1,752,363

Equipment Financings (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Capital Lease Obligations [Abstract]

Schedule of Remaining Future Minimum Lease Payments for Financed Equipment Obligations

				Maintenance
	Minimum			and Sales Tax
	Lease			Obligation
	Payments			Payments
2018 (remaining three months)	$	154,538		$	30,237
2019		613,448			88,599
2020		464,152			67,752
2021		303,228			53,252
2022		262,974			53,493
Thereafter		262,952			40,641
Total payments		2,061,292			333,974
Less amount representing interest		(473,166	)		—
Present value of payments	$	1,588,126		$	333,974

The following schedule sets forth the remaining future minimum lease payments outstanding under financed equipment arrangements, as well as corresponding remaining sales tax and maintenance obligation payments that are expensed and accrued as incurred and due within each respective year ending December 31, as well as the present value of the total amount of the remaining minimum lease payments as of December 31, 2017:


			Maintenance
	Minimum		and Sales Tax
	Lease		Obligation
	Payments		Payments
2018	$	438,737	$	63,602
2019		460,166		67,394
2020		406,868		55,205
2021		302,229		44,281
2022		268,018		38,479
Thereafter		253,951		39,881

Total payments		2,129,969		308,842
Less amount representing interest		570,914		—

Present value of payments	$	1,559,055	$	308,842

Stock-Based Compensation (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Stock Option Activity

A summary of stock option activity for the nine months ended September 30, 2018 is as follows:

						Weighted
						Average
				Weighted		Remaining
	Number of			Average Exercise		Contractual
	Shares			Price Per Share		Term in Years
Outstanding at December 31, 2017		81,482		$	113.68		8.80
Granted		58,994		$	2.96		7.43
Exercised		—			—
Cancelled/forfeited/expired		(25,835	)	$	45.83		8.68
Outstanding at September 30, 2018		114,641		$	72.02		8.79
Vested and unvested expected to vest at September 30, 2018		112,280		$	73.23		8.77

A summary of stock option activity for the years ended December 31, 2016 and 2017 is as follows:


	Number of Shares			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term in Years
Outstanding at December 31, 2015		23,788		$	330.90		8.8

Granted		9,679		$	75.30
Exercised		—			—
Cancelled/forfeited/expired		(3,579	)	$	239.70

Outstanding at December 31, 2016		29,888		$	264.00		8.5

Granted		58,501		$	44.70
Exercised		—			—
Cancelled/forfeited/expired		(6,746	)	$	143.10

Outstanding at December 31, 2017		81,643		$	113.70		8.8

Vested and unvested expected to vest, December 31, 2017		59,142		$	140.10		8.6

Assumptions Used for Determining Fair Value of Stock Options Under Black-Scholes Pricing Model

The assumptions used in the Black-Scholes pricing model for stock options granted during the three and nine months ended September 30, 2018 were as follows:

Stock and exercise prices	$2.75 - $6.00
Expected dividend yield		0.00%
Discount rate-bond equivalent yield	2.73% – 2.97%
Expected life (in years)	5.00 – 5.96
Expected volatility	100% - 120%

The assumptions used in the Black-Scholes pricing model for options granted during the years ended December 31, 2016 and 2017 are as follows:


	2016	2017
Stock and exercise prices	$23.25 - $120.60	$20.817 - $63.90
Expected dividend yield	0.00%	0.00%
Discount rate-bond equivalent yield	0.99% - 2.11%	1.79% - 2.27%
Expected life (in years)	5.13 - 6.08	5.12 - 6.09
Expected volatility	80.0% - 90.0%	70.0% - 90.0%

Summary of RSU Activity

A summary of RSU activity for the nine months ended September 30, 2018 is as follows:

				Weighted
	Number of			Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2017		12,026		$	56.10
Granted		—			—
Vested and issued		(5,833	)	$	45.00
Forfeited		(5,833	)	$	45.00
Outstanding at September 30, 2018		360		$	415.80
Vested and unvested expected to vest at September 30, 2018		360		$	415.80

A summary of RSU activity during 2016 and 2017 is as follows:


				Weighted
	Number of			Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2015		858		$	453.60

Granted		5,527		$	58.80
Vested and issued		(148	)	$	481.50
Forfeited		(429	)	$	400.20

Outstanding at December 31, 2016		5,808		$	80.40

Granted		11,666		$	45.00
Vested and issued		(5,194	)	$	58.80
Forfeited		(250	)	$	63.60

Outstanding at December 31, 2017		12,030		$	56.10

Vested and unvested expected to vest, December 31, 2017		6,197		$	66.90

Effects of Stock-Based Compensation Related to Equity Awards to Employees and Nonemployees on Condensed Statement of Operations and Comprehensive Loss

	For the three months ended				For the nine months ended
	September 30,				September 30,
	2017		2018		2017		2018
Stock Options
Cost of revenues	$	59,720	$	10,150	$	133,105	$	37,150
Research and development expenses		53,405		30,247		121,834		103,267
General and administrative expenses		178,671		57,162		528,406		243,593
Sales and marketing expenses		40,181		15,440		100,327		63,494
Total expenses related to stock options		331,977		112,999		883,672		447,504
RSUs
Cost of revenues		20,417		-		58,717		(18,802	)
Research and development expenses		20,418		-		57,490		13,576
General and administrative expenses		74,521		-		160,927		54,303
Sales and marketing expenses		28,355		-		71,343		15,348
Total stock-based compensation	$	475,688	$	112,999	$	1,232,149	$	511,929

The following table presents the effects of stock-based compensation related to equity awards to employees and nonemployees on the statement of operations during the periods presented:


	Years Ended December 31,
	2016		2017
Stock Options
Cost of revenues	$	115,266	$	142,400
Research and development expenses		123,330		143,300
General and administrative expenses		1,071,490		575,741
Sales and marketing expenses		142,741		68,381

Total expenses related to stock options		1,452,827		929,822
RSUs
Cost of revenues		32,338		48,745
Research and development expenses		30,261		55,941
General and administrative expenses		38,274		160,937
Sales and marketing expenses		40,247		52,036

Total stock-based compensation	$	1,593,947	$	1,247,481

Net Loss per Common Share (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Earnings Per Share [Abstract]

Schedule of Anti-Dilutive Securities Excluded from Computations of Diluted Weighted-Average Shares

The following potentially dilutive securities have been excluded from the computations of diluted weighted-average shares outstanding for the periods presented, as they would be anti-dilutive:

	For the three and nine months ended
	September 30,
	2017		2018
Preferred warrants outstanding (number of common stock equivalents)		17		17
Common warrants outstanding		280,058		4,814,927
RSUs outstanding		12,030		360
Common options outstanding		82,810		114,641
Total anti-dilutive common share equivalents		374,915		4,929,945

The following potentially dilutive securities have been excluded from the computations of diluted weighted-average shares outstanding for the periods presented, as they would be anti-dilutive:


	For the year ended
	December 31,
	2016		2017
Preferred warrants outstanding (number of common stock equivalents)		17		17
Common warrants outstanding		387,465		288,266
RSUs outstanding		5,808		12,030
Common options outstanding		29,888		81,642

Total anti-dilutive common share equivalents		423,178		381,958

Summary of Significant Accounting Policies (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Accounting Policies [Abstract]

Composition of Gross and Net Revenues Recognized

The composition of the Company’s gross and net revenues recognized during the years ended December 31, 2016 and 2017 is as follows:


	For the year ended December 31,
	2016		2017
Commercial revenues recognized upon delivery	$	—	$	15,685,069
Development services revenues recognized upon delivery		240,056		272,350
Commercial revenues recognized upon cash collection		2,983,040		1,225,976

Total gross revenues		3,223,096		17,183,395
Provisions for contractual discounts		—		(5,805,787	)
Provisions for aged non-patient receivables		—		(735,709	)
Provisions for estimated patient receivables		—		(169,479	)
Provisions for other payer-specific sales allowances		—		(5,403,757	)

Net revenues	$	3,223,096	$	5,068,663

Summary of Activity in Gross and Net Accounts Receivable Balances and Reserves

A summary of activity in the Company’s gross and net accounts receivable balances, as well as corresponding reserves, during the year ended December 31, 2017 is as follows:


	Balance at		Amounts			Settlements			Balance at
	December 31,		Recognized			Upon			December 31,
	2016		Upon Delivery			Adjudication			2017
Accounts receivable, gross	$	128,969	$	15,957,419		$	(9,149,325	)	$	6,937,063
Reserve for contractual discounts		—		(5,805,787	)		3,830,938			(1,974,849	)
Reserve for aged non-patient receivables		—		(735,709	)		283,621			(452,088	)
Reserve for estimated patient receivables		—		(169,479	)		81,359			(88,120	)
Reserve for other payer-specific sales allowances		—		(5,403,757	)		2,175,177			(3,228,580	)

Accounts receivable, net	$	128,969	$	3,842,687		$	(2,778,230	)	$	1,193,426

Summary of Third-Party Payers That Represent More Than 10% of Total Net Revenues and Total Net Accounts Receivable and Their Related Percentage

	For the three months ended September 30,						For the nine months ended September 30,
	2017			2018			2017			2018
Medicare and Medicare Advantage		45	%		40	%		41	%		39	%
Blue Cross Blue Shield		16	%		9	%		17	%		14	%
United Healthcare		14	%		6	%		12	%		15	%

	December 31, 2017			September 30, 2018
Blue Cross Blue Shield		27	%		22	%
Medicare and Medicare Advantage		21	%		18	%
United Healthcare		15	%		11	%


	For the year ended December 31,
	2016			2017
Medicare and Medicare Advantage		40	%		39	%
Blue Cross Blue Shield		11	%		19	%
United Healthcare		19	%		12	%


Blue Cross Blue Shield	27	%
Medicare and Medicare Advantage	21	%
United Healthcare	15	%

Fair Value Measurement (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Assumptions Used for Determining Fair Values of Common Stock Warrants

The fair value of the warrants was estimated using a Monte Carlo simulation valuation model using Geometric Brownian Motion, incorporating anticipated future financing events, with the following assumptions:

Beginning stock price	$	10.17
Exercise price	$	4.53
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.48	%
Expected life (in years)		5.00
Expected volatility		99.00	%

The fair value of the warrants was estimated using a Black-Scholes model, incorporating the following assumptions:

Beginning stock price	$	3.89
Exercise price	$	4.53
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.75	%
Expected life (in years)		5.00
Expected volatility		128.69	%

The fair value of the warrants was estimated using a Black-Scholes model, incorporating the following assumptions:

Beginning stock price	$	2.92
Exercise price	$	3.16
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.77	%
Expected life (in years)		5.50
Expected volatility		130.7	%


Stock price	$	81.00
Exercise price	$	117.00
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		1.23	%
Expected life (in years)		5.00
Expected volatility		90.0	%


Stock price	$	63.90
Exercise price	$	75.00
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		1.93	%
Expected life (in years)		5.00
Expected volatility		80.0	%


Stock price	$	41.70
Exercise price	$	45.00
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		1.81	%
Expected life (in years)		5.00
Expected volatility		100.0	%


Stock price	$	22.197
Exercise price	$	25.50
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.09	%
Expected life (in years)		4.50
Expected volatility		100.0	%

Over Allotment Option And Common Stock Warrants [Member]

Assumptions Used for Determining Fair Values of Common Stock Warrants

The fair values of these instruments were estimated using a Black-Scholes valuation model with the following assumptions:


	Overallotment Options			Warrants
Stock price	$	27.90			$	27.90
Exercise price	$	30.993			$	33.00
Expected dividend yield		0.00	%		0.00	%
Discount rate-bond equivalent yield		0.25	%		1.24	%
Expected life (in years)		0.08			5.00
Expected volatility		12.9	%		80.0	%

Common Stock Warrants Outstanding (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Equity Classified Warrants [Abstract]

Summary of Equity-Classified Common Stock Warrant Activity, for Warrants Other than Underlying Unexercised Overallotment Option Warrants

A summary of equity-classified common stock warrant activity for the nine months ended September 30, 2018 is as follows:

					Average
			Weighted		Remaining
	Number of		Average Exercise		Contractual
	Shares		Price Per Share		Term in Years
Outstanding at December 31, 2017		288,196	$	78.86		4.0
Issued		4,406,731	$	3.95
Exercised		—		—
Expired		—		—
Outstanding at September 30, 2018		4,814,927	$	5.44		4.7

A summary of equity-classified common stock warrant activity, for warrants other than those underlying unexercised overallotment option warrants, during 2016 and 2017 is as follows:


						Average
				Weighted		Remaining
	Number of			Average Exercise		Contractual
	Shares			Price Per Share		Term in Years
Outstanding at December 31, 2015		26,140		$	335.40		3.8

Issued		363,021		$	42.00
Exercised		—			—
Expired		(1,696	)	$	900.00

Outstanding at December 31, 2016		387,465		$	57.90		4.6

Issued		128,029		$	60.60
Exercised		(227,228	)	$	33.00
Expired		—			—

Outstanding at December 31, 2017		288,266		$	78.90		4.0

Schedule of Equity-Classified Common Stock Warrants, Outstanding

Further information about equity-classified common stock warrants outstanding at December 31, 2017 is as follows:


Weighted Average Exercise Price			Total Shares Outstanding		Weighted Average Contractual Life (in years)
$	25.50			8,208		4.9
$	33.00			97,009		3.8
$	45.00			47,821		4.6
$	75.00			72,000		4.7
$	117.00			38,784		3.3
$	140.40			19,371		2.1
$	891.60			5,071		1.7

		288,264

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of Provision for Income Taxes

For the years ended December 31, 2016 and 2017, the provision for income taxes was calculated as follows:


	For the year ended December 31,
	2016		2017
Current:
Federal	$	—	$	—
State		2,053		7,624

Total		2,053		7,624
Deferred
Federal		—		—
State		—		—

Total		—		—

Provision for income tax	$	2,053	$	7,624

Reconciles of Income Taxes Computed at Federal Statutory Rate and Provision for Income Taxes

The following table reconciles income taxes computed at the federal statutory rate and the Company’s provision for income taxes:


	For the year ended December 31,
	2016			2017
Income tax at statutory rate	$	(6,255,072	)	$	(7,346,079	)
Change in federal tax rate		—			2,621,803
State liability		(260,835	)		(411,853	)
Permanent items		67,151			214,313
Stock compensation		157,250			72,696
Nondeductible interest		21,548			15,568
Expiration of net operating losses		—			922,307
Research and development credit		(170,950	)		(200,379	)
State rate change		44,421			(18,026	)
Estimated section 382 limitation		9,256,295			1,491,942
Return to provision		—			365,263
Other		96,406			488,264
Valuation allowance		(2,954,161	)		1,791,805

Provision for income tax	$	2,053		$	7,624

Summary of Deferred Tax Assets

The tax effects of carryforwards and other temporary differences that give rise to deferred tax assets consist of the following:


	For the year ended December 31,
	2016			2017
Estimated net operating loss carryforward	$	2,218,618		$	3,355,180
Estimated research and development credits		2,244,047			2,686,666
Accruals and other		2,273,838			2,560,417
Deferred rent		164,821			90,866

		6,901,324			8,693,129
Less valuation allowance		(6,901,324	)		(8,693,129	)

Net deferred tax assets	$	—		$	—

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments

The future minimum lease payments under the amended lease agreement as December 31, 2017 are as follows:


2018	$	1,388,705
2019		1,430,366
2020		855,136
Thereafter		—

Total	$	3,674,207

Selected Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Summary of Selected Quarterly Financial Data

The following is selected quarterly financial data as of and for the periods ending:


	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
December 31, 2016
Balance sheet data:
Cash	$	4,572,750		$	3,751,570		$	678,855		$	4,609,332
Total assets		6,780,830			6,303,153			3,282,549			7,578,326
Total non-current liabilities		3,132,372			3,134,593			2,793,258			2,526,113
Total shareholders’ equity		(489,231	)		(419,402	)		(4,556,158	)		658,661
Statement of operations and comprehensive loss data:
Net revenues	$	221,369		$	662,860		$	1,047,280		$	1,291,587
Cost of revenues		1,474,790			1,669,571			1,876,288			1,899,462
Research and development expenses		728,076			716,279			600,613			668,399
General and administrative expenses		1,487,224			1,517,664			1,918,543			1,636,994
Sales and marketing expenses		1,304,899			1,291,709			1,278,455			1,179,167
Loss from operations		(4,773,620	)		(4,532,363	)		(4,626,619	)		(4,092,435	)
Net loss	$	(4,875,198	)	$	(4,594,174	)	$	(4,743,076	)	$	(4,186,874	)
Net loss per common share:¹
Basic	$	(22.27	)	$	(17.89	)	$	(16.99	)	$	(8.04	)

Diluted	$	(22.27	)	$	(17.89	)	$	(16.99	)	$	(8.04	)

Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic		218,900			256,742			279,023			520,668

Diluted		218,900			256,742			279,023			520,668

¹	Basic and diluted net loss per common share are computed independently for each of the components and quarters presented. Therefore, the sum of quarterly basic and diluted per share information may not equal annual basic and diluted net loss per common share.


	First Quarter			Second Quarter			Third Quarter			Fourth Quarter
December 31, 2017
Balance sheet data:
Cash	$	14,042,388		$	10,000,155		$	5,879,025		$	2,146,611
Total assets		17,933,413			14,653,193			11,120,215			7,378,906
Total non-current liabilities		2,062,544			1,561,520			1,255,939			1,421,527
Total shareholders’ equity		10,418,069			7,342,257			4,026,079			1,296,034
Statement of operations and comprehensive loss data:
Net revenues	$	1,683,065		$	1,278,961		$	1,111,411		$	995,226
Cost of revenues		2,129,454			2,368,705			2,487,054			2,359,909
Research and development expenses		757,258			841,991			856,698			908,800
General and administrative expenses		1,906,635			1,798,026			1,834,771			1,650,097
Sales and marketing expenses		1,278,311			1,746,867			1,675,852			1,642,941
Loss from operations		(4,388,593	)		(5,476,628	)		(5,742,964	)		(5,566,521	)
Net loss	$	(4,432,707	)	$	(5,693,151	)	$	(5,821,306	)	$	(5,666,573	)
Net loss per common share:¹
Basic	$	(6.27	)	$	(6.32	)	$	(5.85	)	$	(5.36	)

Diluted	$	(6.27	)	$	(6.32	)	$	(5.85	)	$	(5.36	)

Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic		707,389			901,007			995,254			1,058,055

Diluted		707,389			901,007			995,254			1,058,055

¹	Basic and diluted net loss per common share are computed independently for each of the components and quarters presented. Therefore, the sum of quarterly basic and diluted per share information may not equal annual basic and diluted net loss per common share.

The Company, Business Activities and Basis of Presentation - Additional Information (Detail)			3 Months Ended	9 Months Ended		12 Months Ended
	Jul. 06, 2018 shares	Sep. 29, 2016	Sep. 30, 2017 USD ($) $ / shares	Sep. 30, 2018 shares	Sep. 30, 2017 USD ($) $ / shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 shares	Sep. 27, 2016 shares
The Company Business Activities And Basis Of Presentation [Line Items]
Stockholders equity reverse stock split ratio	0.03	0.33
Common stock, shares authorized	150,000,000			150,000,000		150,000,000	150,000,000
Description of reverse stock split	On July 6, 2018, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s Certificate of Amendment of Certificate of Incorporation to effect a one-for-thirty reverse stock split of the Company’s outstanding common stock.					On September 27, 2016, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s amended and restated certificate of incorporation to effect a one-for-three reverse stock split of the Company’s outstanding common stock, and to increase the authorized number of shares of the Company’s common stock from 40,000,000 to 150,000,000 shares. The one-for-three reverse stock split was effected on September 29, 2016.
Nonrecurring net revenue recognized on accrual basis associated with cases delivered \| $			$ 102,000		$ 839,000	$ 843,000
Increase (decrease) in net income (loss) per common share on nonrecurring net revenue \| $ / shares			$ (0.10)		$ (0.97)	$ 0.90
Net revenue recorded in excess of commercial cash collections \| $			$ 125,000		$ 1,158,000	$ 1,139,000
Increase decrease in net income (loss) per common share \| $ / shares			$ (0.13)		$ (1.35)	$ 1.20
Maximum [Member]
The Company Business Activities And Basis Of Presentation [Line Items]
Common stock, shares authorized								150,000,000
Minimum [Member]
The Company Business Activities And Basis Of Presentation [Line Items]
Common stock, shares authorized								40,000,000
ASC 606 [Member]
The Company Business Activities And Basis Of Presentation [Line Items]
Performance obligation, description of timing				The duration of time between accession receipt and delivery of a valid assay result to the ordering physician or entity is typically less than two weeks.
Practical expedient, description				The Company does not adjust the transaction price for the effects of a significant financing component, as at contract inception, the Company expects the collection cycle to be one year or less.
ASC 606 [Member] \| Maximum [Member] \| Sales and Marketing Expenses [Member]
The Company Business Activities And Basis Of Presentation [Line Items]
Amortization period				1 year

The Company, Business Activities and Basis of Presentation - Composition of Net Revenues Recognized Disaggregated by Source (Detail) - USD ($)

3 Months Ended

9 Months Ended

12 Months Ended

Sep. 30, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2016

Sep. 30, 2016

Jun. 30, 2016

Mar. 31, 2016

Sep. 30, 2018

Sep. 30, 2017

Dec. 31, 2017

Dec. 31, 2016

Revenue Recognition [Abstract]

Net revenues from contracted payers

^[1]

$ 325,097

$ 422,136

$ 1,019,857

$ 1,655,287

Net revenues from non-contracted payers

373,018

621,881

1,211,309

2,206,414

Development services revenues

63,476

67,394

159,606

211,736

Total net revenues

$ 761,591

$ 995,226

$ 1,111,411

$ 1,278,961

$ 1,683,065

$ 1,291,587

$ 1,047,280

$ 662,860

$ 221,369

$ 2,390,772

$ 4,073,437

$ 5,068,663

$ 3,223,096

[1]	Includes Medicare and Medicare Advantage, as reimbursement amounts are fixed and miscellaneous income from CEE-Sure blood collection tubes.

The Company, Business Activities and Basis of Presentation - Composition of Net Revenues Recognized Disaggregated by Nature (Detail) - USD ($)	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Revenue Recognition [Abstract]
Net commercial revenues recognized upon delivery	$ 698,115		$ 941,783							$ 2,231,166	$ 2,703,424
Development services revenues recognized upon delivery	63,476		67,394							159,606	211,736
Commercial revenues recognized upon cash collection			102,234								1,158,277
Total net revenues	$ 761,591	$ 995,226	$ 1,111,411	$ 1,278,961	$ 1,683,065	$ 1,291,587	$ 1,047,280	$ 662,860	$ 221,369	$ 2,390,772	$ 4,073,437	$ 5,068,663	$ 3,223,096

The Company, Business Activities and Basis of Presentation - Summary of Third-Party Payers That Represent More Than 10% of Total Net Revenues and Total Net Accounts Receivable and Their Related Percentage (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Customer Concentration Risk [Member] \| Net Revenues [Member] \| Blue Cross Blue Shield [Member]
Concentration Risk [Line Items]
Concentration risk percentage	9.00%	16.00%	14.00%	17.00%	19.00%	11.00%
Customer Concentration Risk [Member] \| Net Revenues [Member] \| Medicare and Medicare Advantage [Member]
Concentration Risk [Line Items]
Concentration risk percentage	40.00%	45.00%	39.00%	41.00%	39.00%	40.00%
Customer Concentration Risk [Member] \| Net Revenues [Member] \| United Healthcare [Member]
Concentration Risk [Line Items]
Concentration risk percentage	6.00%	14.00%	15.00%	12.00%	12.00%	19.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| Blue Cross Blue Shield [Member]
Concentration Risk [Line Items]
Concentration risk percentage			22.00%		27.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| Medicare and Medicare Advantage [Member]
Concentration Risk [Line Items]
Concentration risk percentage			18.00%		21.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| United Healthcare [Member]
Concentration Risk [Line Items]
Concentration risk percentage			11.00%		15.00%

Liquidity and Going Concern Uncertainty- Additional Information (Detail) - USD ($)												1 Months Ended			3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 20, 2018	Aug. 13, 2018	Jan. 31, 2018	Jan. 30, 2018	Jan. 30, 2018	Dec. 08, 2017	Aug. 11, 2017	Aug. 09, 2017	Mar. 31, 2017	Oct. 19, 2016	May 04, 2016	May 31, 2018	Feb. 29, 2016	May 31, 2015	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Liquidity And Managements Plans [Line Items]
Cash									$ 14,042,388						$ 8,956,200	$ 2,146,611	$ 5,879,025	$ 10,000,155	$ 14,042,388	$ 4,609,332	$ 678,855	$ 3,751,570	$ 4,572,750	$ 8,956,200	$ 5,879,025	$ 2,146,611	$ 4,609,332	$ 8,821,329
Accumulated deficit															(214,444,005)	(195,249,607)				(173,635,870)				(214,444,005)		(195,249,607)	(173,635,870)
Net loss															(6,047,784)	(5,666,573)	(5,821,306)	$ (5,693,151)	$ (4,432,707)	$ (4,186,874)	$ (4,743,076)	$ (4,594,174)	$ (4,875,198)	(18,558,028)	(15,947,164)	(21,613,737)	$ (18,399,322)
Aggregate net interest-bearing indebtedness																3,100,000										3,100,000
Aggregate net interest-bearing indebtedness due within one year																2,000,000										2,000,000
Unconditional purchase commitment aggregate amount													$ 1,062,500		404,000	611,000								$ 404,000		$ 611,000
Unconditional purchase commitment payment terms																								Quarterly		Quarterly
Unconditional purchase commitment period																								May 31, 2020		May 31, 2020
Shelf registration statement expiration period														May 21, 2018
Public offering, number of common stock and warrants issued	642,438				1,095,153
Beginning stock price	$ 3.285			$ 13.50	$ 13.50
Exercise price of unregistered warrants		$ 4.53		$ 4.53	$ 4.53	$ 25.50	$ 45.00	$ 45.00	$ 75.00		$ 117.00								$ 75.00
Net proceeds from issuance of units, net of issuance expenses	$ 2,200,000	$ 10,200,000
Warrant exercisable for share of common stock		1
Class of warrant or rights, term		5 years			5 years
Aggregate units sold under right offering		11,587
Shares issued in offering	642,438
Proceeds from issuance of common stock, net of issuance costs	$ 2,200,000							$ 2,000,000		$ 9,000,000
Proceeds from exercise of common stock warrants		$ 0					$ 0			$ 564														$ 0	7,498,535	$ 7,498,535
Proceeds from gross exercise of common stock warrants outstanding																										$ 3,200,000
Exercisable warrant available price per share																										$ 33.00
Exercisable warrant available price per share expiration period							2022-08																			2021-10
Proceeds from issuance of common stock	$ 2,500,000	$ 11,600,000					$ 2,200,000
Other non-interest bearing current liabilities																$ 2,700,000										$ 2,700,000
Shelf registration statement expiration period														2018-05
Issuance of unregistered warrants to purchase shares of common stock	762,438	2,549,140		1,095,153	1,095,153	8,208		47,821	72,000		38,784								72,000
Class of warrant or rights, expiration date						Dec. 05, 2022
Class of warrant or rights, first exercisable date						Jun. 05, 2018
Purchase of common stock by underwriters to cover overallotments, number of shares										20,904
Ally Bridge [Member]
Liquidity And Managements Plans [Line Items]
Issuance of warrants to purchase shares of common stock								47,821
Beginning stock price								$ 45.00
Exercise price of unregistered warrants								$ 45.00
Class of warrant or rights, term								5 years
Proceeds from issuance of common stock, net of issuance costs								$ 2,000,000
Proceeds from exercise of common stock warrants							$ 0	$ 0
Exercisable warrant available price per share expiration period								2022-08
Proceeds from issuance of common stock								$ 2,200,000
Prefunded Warrants [Member]
Liquidity And Managements Plans [Line Items]
Issuance of warrants to purchase shares of common stock	120,000
Exercise price of unregistered warrants	$ 3.275
Change in exercise price of warrants	0.01
Series A Preferred Stock [Member]
Liquidity And Managements Plans [Line Items]
Shares issued in offering		11,587
Warrants [Member]
Liquidity And Managements Plans [Line Items]
Aggregate warrants sold under right offering		2,549,140
Class of warrant or rights, expiration date																										Dec. 05, 2022
Class of warrant or rights, first exercisable date																										Jun. 05, 2018
Shelf Registration Statement [Member]
Liquidity And Managements Plans [Line Items]
Shelf registration statement expiration period												May 31, 2021
Minimum public float limit for offering												$ 75,000,000		$ 75,000,000
Public offering, number of common stock and warrants issued											55,406
Beginning stock price											$ 90.00
Exercise price of unregistered warrants											$ 117.00
Class of warrant or rights, term											5 years
Proceeds from issuance of common stock, net of issuance costs											$ 4,300,000
Proceeds from exercise of common stock warrants											0
Proceeds from gross exercise of common stock warrants outstanding											$ 4,500,000
Exercisable warrant available price per share											$ 117.00
Exercisable warrant available price per share expiration period											2021-05
Shelf registration statement expiration period														2018-05
Placement agent agreement, effective date											Apr. 25, 2016
Securities purchase agreement, effective date											Apr. 29, 2016
Issuance of unregistered warrants to purchase shares of common stock											38,784
Private Placement [Member]
Liquidity And Managements Plans [Line Items]
Exercise price of unregistered warrants	$ 3.16
Warrant exercisable for share of common stock	1
Class of warrant or rights, term	5 years
Follow-on Public Offering [Member]
Liquidity And Managements Plans [Line Items]
Public offering, number of common stock and warrants issued					1,095,153
Beginning stock price				$ 13.50	$ 13.50
Exercise price of unregistered warrants	$ 3.16	$ 4.53		$ 4.53	$ 4.53
Class of warrant or rights, term	5 years	5 years			5 years
Proceeds from issuance of common stock, net of issuance costs					$ 13,300,000
Proceeds from exercise of common stock warrants			$ 0		0
Proceeds from gross exercise of common stock warrants outstanding					$ 16,400,000
Exercisable warrant available price per share					$ 15.00
Exercisable warrant available price per share expiration period					2023-01
April 2014 Credit Facility [Member]
Liquidity And Managements Plans [Line Items]
Aggregate net interest-bearing indebtedness															1,700,000		3,300,000							1,700,000	3,300,000
Aggregate net interest-bearing indebtedness due within one year															$ 693,000		$ 2,400,000							$ 693,000	$ 2,400,000
Minimum [Member]
Liquidity And Managements Plans [Line Items]
Unconditional purchase commitment, quarterly payment amount													$ 62,500
Maximum [Member]
Liquidity And Managements Plans [Line Items]
Issuance of warrants to purchase shares of common stock				1,095,153	1,095,153
Purchase of common stock by underwriters to cover overallotments, number of shares										45,500
Maximum [Member] \| Prefunded Warrants [Member]
Liquidity And Managements Plans [Line Items]
Issuance of warrants to purchase shares of common stock	120,000
Maximum [Member] \| Shelf Registration Statement [Member]
Liquidity And Managements Plans [Line Items]
Aggregate offering price												$ 50,000,000		$ 50,000,000
Maximum [Member] \| Follow-on Public Offering [Member]
Liquidity And Managements Plans [Line Items]
Issuance of warrants to purchase shares of common stock				1,095,153	1,095,153
Subsequent Event [Member]
Liquidity And Managements Plans [Line Items]
Beginning stock price	$ 3.285
Exercise price of unregistered warrants		$ 4.53		$ 4.53	$ 4.53
Net proceeds from issuance of units, net of issuance expenses	$ 2,200,000	$ 10,200,000
Warrant exercisable for share of common stock		1
Shares issued in offering	642,438
Aggregate warrants sold under right offering		11,587
Subsequent Event [Member] \| Series A Preferred Stock [Member]
Liquidity And Managements Plans [Line Items]
Shares issued in offering		11,587
Subsequent Event [Member] \| Warrants [Member]
Liquidity And Managements Plans [Line Items]
Exercise price of unregistered warrants				15.00	$ 15.00
Class of warrant or rights, term					5 years
Aggregate warrants sold under right offering		2,549,140
Subsequent Event [Member] \| Private Placement [Member]
Liquidity And Managements Plans [Line Items]
Exercise price of unregistered warrants	$ 3.16
Warrant exercisable for share of common stock	1
Class of warrant or rights, term	5 years
Subsequent Event [Member] \| Follow-on Public Offering [Member]
Liquidity And Managements Plans [Line Items]
Beginning stock price				13.50	$ 13.50
Exercise price of unregistered warrants				$ 15.00	$ 15.00
Class of warrant or rights, term					5 years
Proceeds from issuance of common stock, net of issuance costs				$ 13,300,000	$ 13,300,000
Proceeds from exercise of common stock warrants			$ 0		0
Proceeds from gross exercise of common stock warrants outstanding					$ 16,400,000
Exercisable warrant available price per share					$ 4.53
Exercisable warrant available price per share expiration period					2023-01
Subsequent Event [Member] \| Maximum [Member] \| Warrants [Member]
Liquidity And Managements Plans [Line Items]
Issuance of warrants to purchase shares of common stock				1,095,153	1,095,153
Subsequent Event [Member] \| Maximum [Member] \| Follow-on Public Offering [Member]
Liquidity And Managements Plans [Line Items]
Issuance of warrants to purchase shares of common stock				1,095,153	1,095,153
Roth Capital Partners, LLC, WestPark Capital and Chardan Capital [Member]
Liquidity And Managements Plans [Line Items]
Beginning stock price									$ 64.50										$ 64.50
Exercise price of unregistered warrants									$ 75.00										$ 75.00
Shares issued in offering									144,000
Proceeds from issuance of common stock, net of issuance costs									$ 8,600,000
Proceeds from exercise of common stock warrants									$ 0
Placement agent agreement, effective date									Mar. 28, 2017
Issuance of unregistered warrants to purchase shares of common stock									72,000										72,000
Class of warrant or rights, expiration date									Oct. 01, 2022
Dawson James Securities, Inc and WestPark Capital [Member]
Liquidity And Managements Plans [Line Items]
Beginning stock price						$ 20.40
Exercise price of unregistered warrants						$ 25.50
Shares issued in offering						164,166
Proceeds from issuance of common stock, net of issuance costs						$ 2,900,000
Placement agent agreement, effective date						Dec. 05, 2017
Issuance of unregistered warrants to purchase shares of common stock						8,208
Class of warrant or rights, expiration date						Dec. 05, 2022
Class of warrant or rights, first exercisable date						Jun. 05, 2018

Equipment Financings - Schedule of Remaining Future Minimum Lease Payments for Financed Equipment Obligations (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Capital Lease Obligations [Abstract]
2018 (remaining three months)	$ 154,538
2019	613,448	$ 460,166
2020	464,152	406,868
2021	303,228	302,229
2022	262,974	268,018
Thereafter	262,952	253,951
Total payments	2,061,292	2,129,969
Less amount representing interest	(473,166)	(570,914)
Present value of payments	1,588,126	1,559,055
2018 (remaining three months)	30,237
2019	88,599
2020	67,752
2021	53,252
2022	53,493
Thereafter	40,641
Total payments	333,974	309,000
Present value of payments	$ 333,974
2018		438,737
2018		63,602
2019		67,394
2020		55,205
2021		44,281
2022		38,479
Thereafter		39,881
Total payments		308,842
Present value of payments		$ 308,842

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Shares Outstanding, Beginning Balance	81,482	29,888	23,788
Number of Shares, Granted	58,994	58,501	9,679
Number of Shares, Cancelled/forfeited/expired	(25,835)	(6,746)	(3,579)
Number of Shares Outstanding, Ending Balance	114,641	81,482	29,888	23,788
Number of Shares, Vested and unvested expected to vest, Ending Balance	112,280	59,142
Weighted Average Exercise Price Per Share, Outstanding, Beginning Balance	$ 113.68	$ 264.00	$ 330.90
Weighted Average Exercise Price Per Share, Granted	2.96	44.70	75.30
Weighted Average Exercise Price Per Share, Cancelled/forfeited/expired	45.83	143.10	239.70
Weighted Average Exercise Price Per Share, Outstanding, Ending Balance	72.02	113.68	$ 264.00	$ 330.90
Weighted Average Exercise Price Per Share, Vested and unvested expected to vest, Ending Balance	$ 73.23	$ 140.10
Weighted Average Remaining Contractual Term in Years, Outstanding	8 years 9 months 14 days	8 years 9 months 18 days	8 years 6 months	8 years 9 months 18 days
Weighted Average Remaining Contractual Term in Years, Granted	7 years 5 months 4 days
Weighted Average Remaining Contractual Term in Years, Cancelled/forfeited/expired	8 years 8 months 4 days
Weighted Average Remaining Contractual Term in Years, Vested and unvested expected to vest	8 years 9 months 7 days	8 years 7 months 6 days
Scenario, Previously Reported [Member]
Number of Shares Outstanding, Beginning Balance	81,643
Number of Shares Outstanding, Ending Balance		81,643
Weighted Average Exercise Price Per Share, Outstanding, Beginning Balance	$ 113.70
Weighted Average Exercise Price Per Share, Outstanding, Ending Balance		$ 113.70

Stock-Based Compensation - Assumptions Used for Determining Fair Value of Stock Options Under Black-Scholes Pricing Model (Detail) - $ / shares	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock and exercise prices	$ 2.75	$ 2.75	$ 20.817	$ 23.25
Discount rate-bond equivalent yield	2.73%	2.73%	1.79%	0.99%
Expected life (in years)	5 years	5 years	5 years 1 month 13 days	5 years 1 month 17 days
Expected volatility	100.00%	100.00%	70.00%	80.00%
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock and exercise prices	$ 6.00	$ 6.00	$ 63.90	$ 120.60
Discount rate-bond equivalent yield	2.97%	2.97%	2.27%	2.11%
Expected life (in years)	5 years 11 months 15 days	5 years 11 months 15 days	6 years 1 month 2 days	6 years 29 days
Expected volatility	120.00%	120.00%	90.00%	90.00%

Stock-Based Compensation - Summary of RSU Activity (Detail) - RSUs [Member] - $ / shares		9 Months Ended	12 Months Ended
	Jun. 12, 2014	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares Outstanding, Beginning Balance		12,026	5,808	858
Number of Shares, Granted	494	0	11,666	5,527
Number of share, Vested and issued		(5,833)	(5,194)	(148)
Number of share, Forfeited		(5,833)	(250)	(429)
Number of Shares Outstanding, Ending Balance		360	12,026	5,808
Number of Shares, Vested and unvested expected to vest, Ending Balance		360	6,197
Weighted Average Grand Date Fair Value, Outstanding, Beginning Balance		$ 56.10	$ 80.40	$ 453.60
Weighted Average Grand Date Fair Value, Granted		0	45.00	58.80
Weighted Average Grand Date Fair Value,Vested and issued		45.00	58.80	481.50
Weighted Average Grand Date Fair Value, Forfeited		45.00	63.60	400.20
Weighted Average Grand Date Fair Value, Outstanding, Ending Balance		415.80	56.10	$ 80.40
Weighted Average Grant Date Fair Value, Vested and unvested expected to vest, Ending Balance		$ 415.80	$ 66.90
Scenario, Previously Reported [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares Outstanding, Beginning Balance		12,030
Number of Shares Outstanding, Ending Balance			12,030

Stock-Based Compensation - Effects of Stock-Based Compensation Related to Equity Awards to Employees and Nonemployees on Condensed Statement of Operations and Comprehensive Loss (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 112,999	$ 331,977	$ 447,504	$ 883,672	$ 929,822	$ 1,452,827
Stock Options [Member] \| Cost of revenues [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	10,150	59,720	37,150	133,105	142,400	115,266
Stock Options [Member] \| Research and Development Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	30,247	53,405	103,267	121,834	143,300	123,330
Stock Options [Member] \| General and Administrative Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	57,162	178,671	243,593	528,406	575,741	1,071,490
Stock Options [Member] \| Sales and Marketing Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	15,440	40,181	63,494	100,327	68,381	142,741
RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 112,999	475,688	511,929	1,232,149	1,247,481	1,593,947
RSUs [Member] \| Cost of revenues [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		20,417	(18,802)	58,717	48,745	32,338
RSUs [Member] \| Research and Development Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		20,418	13,576	57,490	55,941	30,261
RSUs [Member] \| General and Administrative Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		74,521	54,303	160,927	160,937	38,274
RSUs [Member] \| Sales and Marketing Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		$ 28,355	$ 15,348	$ 71,343	$ 52,036	$ 40,247

Common Stock Warrants Outstanding - Summary of Equity-Classified Common Stock Warrant Activity (Detail) - Warrants [Member] - $ / shares		9 Months Ended	12 Months Ended
	Dec. 08, 2017	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class Of Warrant Or Right [Line Items]
Number of Shares, Outstanding, Beginning Balance		288,196	387,465	26,140
Number of Shares, Issued	8,208	4,406,731	128,029	363,021
Number of Shares, Exercised			(227,228)
Number of Shares, Expired				(1,696)
Number of Shares, Outstanding, Ending Balance		4,814,927	288,196	387,465	26,140
Weighted Average Exercise Price Per Share, Outstanding, Beginning Balance		$ 78.86	$ 57.90	$ 335.40
Weighted Average Exercise Price Per Share, Issued		3.95	60.60	42.00
Weighted Average Exercise Price Per Share, Exercised			33.00
Weighted Average Exercise Price Per Share, Expired				900.00
Weighted Average Exercise Price Per Share, Outstanding, Ending Balance		$ 5.44	$ 78.86	$ 57.90	$ 335.40
Average Remaining Contractual Term (in years)		4 years 8 months 12 days	4 years	4 years 7 months 6 days	3 years 9 months 18 days

Net Loss per Common Share - Additional Information (Detail) - Prefunded Warrants [Member]	Sep. 20, 2018 $ / shares shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Issuance of warrants to purchase shares of common stock \| shares	120,000
Change in exercise price of warrants \| $ / shares	$ 0.01

Net Loss per Common Share - Schedule of Anti-Dilutive Securities Excluded from Computations of Diluted Weighted-Average Shares (Detail) - shares	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	4,929,945	374,915	4,929,945	374,915	381,958	423,178
Warrants Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	4,814,927	280,058	4,814,927	280,058	288,266	387,465
RSUs Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	360	12,030	360	12,030	12,030	5,808
Preferred Warrants Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	17	17	17	17	17	17
Common Options Outstanding [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	114,641	82,810	114,641	82,810	81,642	29,888

Summary of Significant Accounting Policies - Additional Information (Detail)			3 Months Ended									9 Months Ended		12 Months Ended
	Jul. 06, 2018 shares	Sep. 29, 2016	Sep. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares	Sep. 30, 2017 USD ($) $ / shares	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) shares	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2018 USD ($) shares	Sep. 30, 2017 USD ($) $ / shares	Dec. 31, 2017 USD ($) Segment $ / shares shares	Dec. 31, 2016 USD ($) shares	Sep. 27, 2016 shares
Summary Of Significant Accounting Policies [Line Items]
Stockholders equity reverse stock split ratio	0.03	0.33
Common stock, shares authorized \| shares	150,000,000		150,000,000	150,000,000				150,000,000				150,000,000		150,000,000	150,000,000
Description of reverse stock split	On July 6, 2018, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s Certificate of Amendment of Certificate of Incorporation to effect a one-for-thirty reverse stock split of the Company’s outstanding common stock.													On September 27, 2016, the Company’s stockholders approved, and the Company filed, an amendment to the Company’s amended and restated certificate of incorporation to effect a one-for-three reverse stock split of the Company’s outstanding common stock, and to increase the authorized number of shares of the Company’s common stock from 40,000,000 to 150,000,000 shares. The one-for-three reverse stock split was effected on September 29, 2016.
Nonrecurring net revenue recognized on accrual basis associated with cases delivered					$ 102,000								$ 839,000	$ 843,000
Increase (decrease) in net income (loss) per common share on nonrecurring net revenue \| $ / shares					$ 0.10								$ 0.97	$ (0.90)
Net revenue recorded in excess of commercial cash collections					$ 125,000								$ 1,158,000	$ 1,139,000
Increase decrease in net income (loss) per common share \| $ / shares					$ 0.13								$ 1.35	$ (1.20)
Number of reportable segments \| Segment														1
Number of suppliers														one supplier
Depreciation and amortization expense												$ 580,366	$ 394,708	$ 575,717	$ 322,029
Research and development expenses			$ 1,089,746	$ 908,800	$ 856,698	$ 841,991	$ 757,258	$ 668,399	$ 600,613	$ 716,279	$ 728,076	$ 3,179,612	$ 2,455,947	3,364,747	2,713,367
Accrual for interest or penalties for income taxes				$ 0				$ 0						0	0
Interest or penalties expense on income taxes														$ 0	$ 0
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Common stock, shares authorized \| shares																40,000,000
Estimated useful life of assets														3 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Common stock, shares authorized \| shares																150,000,000
Estimated useful life of assets														7 years

Summary of Significant Accounting Policies - Composition of Gross and Net Revenues Recognized (Detail) - USD ($)	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Revenue Recognition [Abstract]
Commercial revenues recognized upon delivery												$ 15,685,069
Development services revenues recognized upon delivery												272,350	$ 240,056
Commercial revenues recognized upon cash collection												1,225,976	2,983,040
Total gross revenues												17,183,395	3,223,096
Provisions for contractual discounts												(5,805,787)
Provisions for aged non-patient receivables												(735,709)
Provisions for estimated patient receivables												(169,479)
Provisions for other payer-specific sales allowances												(5,403,757)
Total net revenues	$ 761,591	$ 995,226	$ 1,111,411	$ 1,278,961	$ 1,683,065	$ 1,291,587	$ 1,047,280	$ 662,860	$ 221,369	$ 2,390,772	$ 4,073,437	$ 5,068,663	$ 3,223,096

Summary of Significant Accounting Policies - Summary of Activity in Gross and Net Accounts Receivable Balances and Reserves (Detail)	12 Months Ended
	Dec. 31, 2017 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Gross and net accounts receivable, Beginning Balance	$ 128,969
Amounts Recognized Upon Delivery	3,842,687
Settlements Upon Adjudication	(2,778,230)
Gross and net accounts receivable, Ending Balance	1,193,426
Accounts Receivable Gross [Member]
Summary Of Significant Accounting Policies [Line Items]
Gross and net accounts receivable, Beginning Balance	128,969
Amounts Recognized Upon Delivery	15,957,419
Settlements Upon Adjudication	(9,149,325)
Gross and net accounts receivable, Ending Balance	6,937,063
Reserve for Contractual Discounts [Member]
Summary Of Significant Accounting Policies [Line Items]
Amounts Recognized Upon Delivery	(5,805,787)
Settlements Upon Adjudication	3,830,938
Gross and net accounts receivable, Ending Balance	(1,974,849)
Reserve for Aged Non-patient Receivables [Member]
Summary Of Significant Accounting Policies [Line Items]
Amounts Recognized Upon Delivery	(735,709)
Settlements Upon Adjudication	283,621
Gross and net accounts receivable, Ending Balance	(452,088)
Reserve for Estimated Patient Receivables [Member]
Summary Of Significant Accounting Policies [Line Items]
Amounts Recognized Upon Delivery	(169,479)
Settlements Upon Adjudication	81,359
Gross and net accounts receivable, Ending Balance	(88,120)
Reserve for Other Payer-specific Sales Allowances [Member]
Summary Of Significant Accounting Policies [Line Items]
Amounts Recognized Upon Delivery	(5,403,757)
Settlements Upon Adjudication	2,175,177
Gross and net accounts receivable, Ending Balance	$ (3,228,580)

Summary of Significant Accounting Policies - Summary of Third-Party Payers That Represent More Than 10% of Total Net Revenues and Total Net Accounts Receivable and Their Related Percentage (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Customer Concentration Risk [Member] \| Net Revenues [Member] \| Medicare and Medicare Advantage [Member]
Concentration Risk [Line Items]
Concentration risk percentage	40.00%	45.00%	39.00%	41.00%	39.00%	40.00%
Customer Concentration Risk [Member] \| Net Revenues [Member] \| Blue Cross Blue Shield [Member]
Concentration Risk [Line Items]
Concentration risk percentage	9.00%	16.00%	14.00%	17.00%	19.00%	11.00%
Customer Concentration Risk [Member] \| Net Revenues [Member] \| United Healthcare [Member]
Concentration Risk [Line Items]
Concentration risk percentage	6.00%	14.00%	15.00%	12.00%	12.00%	19.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| Medicare and Medicare Advantage [Member]
Concentration Risk [Line Items]
Concentration risk percentage			18.00%		21.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| Blue Cross Blue Shield [Member]
Concentration Risk [Line Items]
Concentration risk percentage			22.00%		27.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| United Healthcare [Member]
Concentration Risk [Line Items]
Concentration risk percentage			11.00%		15.00%

Sales of Equity Securities - Additional Information (Detail) - USD ($)														1 Months Ended		9 Months Ended		12 Months Ended
	Jan. 18, 2019	Sep. 20, 2018	Aug. 13, 2018	Jan. 31, 2018	Jan. 30, 2018	Jan. 30, 2018	Dec. 08, 2017	Aug. 11, 2017	Aug. 09, 2017	Mar. 31, 2017	Oct. 19, 2016	May 04, 2016	Dec. 21, 2015	May 31, 2018	May 31, 2015	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class Of Stock [Line Items]
Increase in capital shares value																			$ 1,400,000
Overallotment issued to underwriter to purchase common stock, period											30 days
Public offering, number of shares issued		642,438
Beginning stock price		$ 3.285			$ 13.50	$ 13.50
Proceeds from issuance of common stock		$ 2,500,000	$ 11,600,000					$ 2,200,000
Common stock, shares issued																3,937,226		1,181,179	583,313
Common stock issuance costs																			$ 79,000	$ 42,000
Shelf registration statement expiration period															2018-05
Public offering, number of common stock and warrants issued		642,438				1,095,153
Issuance of unregistered warrants to purchase shares of common stock		762,438	2,549,140		1,095,153	1,095,153	8,208		47,821	72,000		38,784
Exercise price of unregistered warrants			$ 4.53		$ 4.53	$ 4.53	$ 25.50	$ 45.00	$ 45.00	$ 75.00		$ 117.00
Class of warrant or rights, term			5 years			5 years
Issuance of warrants to purchase shares of common stock, grant date fair value		$ 2,000,000	$ 8,400,000			$ 9,700,000	$ 100,000		$ 1,500,000	$ 2,800,000	$ 5,200,000	$ 2,000,000
Net cash proceeds from sale of securities		2,200,000							$ 2,000,000		9,000,000
Proceeds from exercise of common stock warrants			0					$ 0			564					$ 0	$ 7,498,535	$ 7,498,535
Exercisable warrant available price per share expiration period								2022-08										2021-10
Class of warrant or rights, expiration date							Dec. 05, 2022
Class of warrant or rights, first exercisable date							Jun. 05, 2018
Shelf registration statement expiration period															May 21, 2018
Net proceeds from issuance of units, net of issuance expenses		2,200,000	$ 10,200,000
Aggregate units sold under right offering			11,587
Warrant exercisable for share of common stock			1
Series A Preferred Stock convertible to common stock, conversion price			$ 4.53
Warrant term							5 years		5 years	5 years		5 years
Offering fees and costs recorded within common stock issuance costs as an offset to additional paid in capital		$ 300,000	$ 1,400,000			$ 1,400,000	$ 428,000		$ 176,000	$ 728,000	$ 1,040,000	$ 653,000
Subsequent Event [Member]
Class Of Stock [Line Items]
Public offering, number of shares issued		642,438
Beginning stock price		$ 3.285
Exercise price of unregistered warrants			$ 4.53		$ 4.53	$ 4.53
Issuance of warrants to purchase shares of common stock, grant date fair value			$ 8.4
Net proceeds from issuance of units, net of issuance expenses		$ 2,200,000	$ 10,200,000
Aggregate warrants sold under right offering			11,587
Warrant exercisable for share of common stock			1
Warrant term			5 years
Roth Capital Partners, LLC, WestPark Capital and Chardan Capital [Member]
Class Of Stock [Line Items]
Public offering, number of shares issued										144,000
Beginning stock price										$ 64.50
Placement agent agreement, effective date										Mar. 28, 2017
Issuance of unregistered warrants to purchase shares of common stock										72,000
Exercise price of unregistered warrants										$ 75.00
Issuance of warrants to purchase shares of common stock, grant date fair value										$ 2,800,000
Cost directly associated with offering										700,000
Net cash proceeds from sale of securities										8,600,000
Proceeds from exercise of common stock warrants										$ 0
Class of warrant or rights, expiration date										Oct. 01, 2022
Dawson James Securities, Inc and WestPark Capital [Member]
Class Of Stock [Line Items]
Public offering, number of shares issued							164,166
Beginning stock price							$ 20.40
Placement agent agreement, effective date							Dec. 05, 2017
Issuance of unregistered warrants to purchase shares of common stock							8,208
Exercise price of unregistered warrants							$ 25.50
Issuance of warrants to purchase shares of common stock, grant date fair value							$ 100,000
Cost directly associated with offering							400,000
Net cash proceeds from sale of securities							$ 2,900,000
Class of warrant or rights, expiration date							Dec. 05, 2022
Class of warrant or rights, first exercisable date							Jun. 05, 2018
Maximum [Member]
Class Of Stock [Line Items]
Issuance of warrants to purchase shares of common stock					1,095,153	1,095,153
Shelf Registration Statement [Member]
Class Of Stock [Line Items]
Beginning stock price												$ 90.00
Shelf registration statement expiration period															2018-05
Minimum public float limit for offering														$ 75,000,000	$ 75,000,000
Placement agent agreement, effective date												Apr. 25, 2016
Securities purchase agreement, effective date												Apr. 29, 2016
Public offering, number of common stock and warrants issued												55,406
Issuance of unregistered warrants to purchase shares of common stock												38,784
Exercise price of unregistered warrants												$ 117.00
Class of warrant or rights, term												5 years
Issuance of warrants to purchase shares of common stock, grant date fair value												$ 2,000,000
Cost directly associated with offering												700,000
Net cash proceeds from sale of securities												4,300,000
Proceeds from exercise of common stock warrants												0
Proceeds from gross exercise of common stock warrants outstanding												$ 4,500,000
Exercisable warrant available price per share expiration period												2021-05
Shelf registration statement expiration period														May 31, 2021
Shelf Registration Statement [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Aggregate offering price														$ 50,000,000	$ 50,000,000
Follow-on Public Offering [Member]
Class Of Stock [Line Items]
Beginning stock price					$ 13.50	$ 13.50
Public offering, number of common stock and warrants issued						1,095,153
Exercise price of unregistered warrants		$ 3.16	$ 4.53		4.53	$ 4.53
Class of warrant or rights, term		5 years	5 years			5 years
Issuance of warrants to purchase shares of common stock, grant date fair value						$ 9,700,000
Cost directly associated with offering						1,400,000
Net cash proceeds from sale of securities						13,300,000
Proceeds from exercise of common stock warrants				$ 0		$ 0
Exercisable warrant available price per share expiration period						2023-01
Private offering, number of common stock and warrants issued						1,095,153
Follow-on Public Offering [Member] \| Subsequent Event [Member]
Class Of Stock [Line Items]
Beginning stock price					13.50	$ 13.50
Exercise price of unregistered warrants					$ 15.00	$ 15.00
Class of warrant or rights, term						5 years
Issuance of warrants to purchase shares of common stock, grant date fair value					$ 9,700,000
Net cash proceeds from sale of securities					$ 13,300,000	$ 13,300,000
Proceeds from exercise of common stock warrants				$ 0		$ 0
Exercisable warrant available price per share expiration period						2023-01
Private offering, number of common stock and warrants issued					1,095,153	1,095,153
Warrant term					5 years
Offering fees and costs recorded within common stock issuance costs as an offset to additional paid in capital					$ 1,400,000
Follow-on Public Offering [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Issuance of warrants to purchase shares of common stock					1,095,153	1,095,153
Follow-on Public Offering [Member] \| Maximum [Member] \| Subsequent Event [Member]
Class Of Stock [Line Items]
Issuance of warrants to purchase shares of common stock					1,095,153	1,095,153
Private Placement [Member]
Class Of Stock [Line Items]
Exercise price of unregistered warrants		$ 3.16
Class of warrant or rights, term		5 years
Warrant exercisable for share of common stock		1
Private Placement [Member] \| Subsequent Event [Member]
Class Of Stock [Line Items]
Exercise price of unregistered warrants		$ 3.16
Class of warrant or rights, term		5 years
Warrant exercisable for share of common stock		1
Common Stock Purchase Agreement [Member]
Class Of Stock [Line Items]
Proceeds from issuance of common stock																			$ 544,000
Aggregate common stock shares purchase																			5,771
Aspire Capital Fund, LLC [Member]
Class Of Stock [Line Items]
Common stock, shares issued													1,833
Ally Bridge [Member]
Class Of Stock [Line Items]
Beginning stock price									$ 45.00
Proceeds from issuance of common stock									$ 2,200,000
Common stock issuance costs									$ 200,000
Exercise price of unregistered warrants									$ 45.00
Class of warrant or rights, term									5 years
Issuance of warrants to purchase shares of common stock, grant date fair value									$ 1,500,000
Net cash proceeds from sale of securities									2,000,000
Proceeds from exercise of common stock warrants								$ 0	$ 0
Exercisable warrant available price per share expiration period									2022-08
Private offering, number of common stock and warrants issued									48,888
Issuance of warrants to purchase shares of common stock									47,821
Common Stock [Member] \| Subsequent Event [Member]
Class Of Stock [Line Items]
Public offering, number of shares issued	999,000
Beginning stock price	$ 2.25
Net cash proceeds from sale of securities	$ 2,000,000
Common Stock [Member] \| Aspire Capital Fund, LLC [Member]
Class Of Stock [Line Items]
Increase in capital shares value													$ 15,000,000
Overallotment issued to underwriter to purchase common stock, period													30 months
Public offering, number of shares issued													6,944
Beginning stock price													$ 144.00
Proceeds from issuance of common stock													$ 1,000,000
Second Offering [Member] \| Roth Capital Partners, LLC, WestPark Capital and Chardan Capital [Member]
Class Of Stock [Line Items]
Public offering, number of shares issued										144,000
Beginning stock price										$ 64.50
Placement agent agreement, effective date										Mar. 28, 2017
Issuance of unregistered warrants to purchase shares of common stock										72,000
Exercise price of unregistered warrants										$ 75.00
Class of warrant or rights, term										5 years
Issuance of warrants to purchase shares of common stock, grant date fair value										$ 2,800,000
Cost directly associated with offering										700,000
Net cash proceeds from sale of securities										$ 8,600,000
Warrants [Member]
Class Of Stock [Line Items]
Class of warrant or rights, expiration date																		Dec. 05, 2022
Class of warrant or rights, first exercisable date																		Jun. 05, 2018
Aggregate warrants sold under right offering			2,549,140
Warrants [Member] \| Subsequent Event [Member]
Class Of Stock [Line Items]
Exercise price of unregistered warrants					$ 15.00	$ 15.00
Class of warrant or rights, term						5 years
Aggregate warrants sold under right offering			2,549,140
Warrants [Member] \| Maximum [Member] \| Subsequent Event [Member]
Class Of Stock [Line Items]
Issuance of warrants to purchase shares of common stock					1,095,153	1,095,153
Prefunded Warrants [Member]
Class Of Stock [Line Items]
Exercise price of unregistered warrants		$ 3.275
Issuance of warrants to purchase shares of common stock		120,000
Change in exercise price of warrants		$ 0.01
Prefunded Warrants [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Issuance of warrants to purchase shares of common stock		120,000
Series A Preferred Stock [Member]
Class Of Stock [Line Items]
Public offering, number of shares issued			11,587
Series A Preferred Stock [Member] \| Subsequent Event [Member]
Class Of Stock [Line Items]
Public offering, number of shares issued			11,587

Fair Value Measurement - Additional Information (Detail) - USD ($)										9 Months Ended		12 Months Ended
	Sep. 20, 2018	Aug. 13, 2018	Jan. 30, 2018	Jan. 30, 2018	Dec. 08, 2017	Aug. 09, 2017	Mar. 31, 2017	Oct. 19, 2016	May 04, 2016	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Aug. 11, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning stock price	$ 3.285		$ 13.50	$ 13.50
Fixed asset purchases as equipment financings obligations										$ 270,000	$ 363,000	$ 719,000	$ 975,000
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value	$ 2,000,000	$ 8,400,000		$ 9,700,000	$ 100,000	$ 1,500,000	$ 2,800,000	$ 5,200,000	$ 2,000,000
Issuance of unregistered warrants to purchase shares of common stock	762,438	2,549,140	1,095,153	1,095,153	8,208	47,821	72,000		38,784
Overallotment issued to underwriter to purchase common stock, period								30 days
Purchase of common stock by underwriters to cover overallotments, per share								$ 30.99
Purchase of common stock by underwriters to cover overallotments, number of shares								20,904
Common stock, par value								$ 0.027		$ 0.0001		$ 0.0001	$ 0.0001
Grant date fair values of overallotment options								$ 800,000
Estimated grant date fair value of warrants	$ 2.57	$ 3.30	$ 8.82	$ 8.82				$ 17.10
Exercise price of unregistered warrants		$ 4.53	$ 4.53	$ 4.53	$ 25.50	$ 45.00	$ 75.00		$ 117.00					$ 45.00
Class of warrant or rights, term		5 years		5 years
Common stock warrants outstanding, intrinsic value												$ 0
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Issuance of overallotment options to purchase common stock shares								45,500
Purchase of common stock by underwriters to cover overallotments, number of shares								45,500
Issuance of warrants to purchase shares of common stock			1,095,153	1,095,153
Roth Capital Partners, LLC and Feltl and Company, Inc. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Issuance of unregistered warrants to purchase shares of common stock								303,333
Subsequent Event [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning stock price	3.285
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value		$ 8.4
Exercise price of unregistered warrants		$ 4.53	$ 4.53	$ 4.53
Warrants [Member] \| Exercise Price [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Warrant exercise price					15.60	30.90	39.30	17.10	51.60
Estimated Fair Value Measurements, Nonrecurring [Member] \| Level 3 Inputs [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed asset purchases as equipment financings obligations										$ 274,000		$ 975,000	$ 719,000
Prefunded Warrants [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Exercise price of unregistered warrants	$ 3.275
Issuance of warrants to purchase shares of common stock	120,000
Common stock warrants outstanding, intrinsic value	$ 350,000
Prefunded Warrants [Member] \| Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Issuance of warrants to purchase shares of common stock	120,000
Follow-on Public Offering [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning stock price			13.50	$ 13.50
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value				$ 9,700,000
Exercise price of unregistered warrants	$ 3.16	$ 4.53	$ 4.53	$ 4.53
Class of warrant or rights, term	5 years	5 years		5 years
Follow-on Public Offering [Member] \| Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Issuance of warrants to purchase shares of common stock			1,095,153	1,095,153
Follow-on Public Offering [Member] \| Subsequent Event [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning stock price			$ 13.50	$ 13.50
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value			$ 9,700,000
Exercise price of unregistered warrants			$ 15.00	$ 15.00
Class of warrant or rights, term				5 years
Follow-on Public Offering [Member] \| Subsequent Event [Member] \| Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Issuance of warrants to purchase shares of common stock			1,095,153	1,095,153

Balance Sheet Details - Schedule of Fixed Assets and Accrued Liabilities (Detail) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Fixed Assets
Machinery and equipment	$ 2,810,226	$ 2,841,388	$ 2,728,468
Furniture and office equipment	157,391	147,976	143,726
Computer equipment and software	1,430,669	1,637,034	620,582
Leasehold improvements	570,174	553,529	517,968
Financed equipment	2,526,081	2,294,762	1,559,690
Construction in process	128,377	2,975	169,896
Total fixed assets, gross	7,622,918	7,477,664	5,740,330
Less accumulated depreciation and amortization	(4,721,924)	(4,354,097)	(3,933,999)
Total fixed assets, net	2,900,994	3,123,567	1,806,331
Accrued Liabilities
Interest payable		326,602	20,776
Accrued payroll	387,162	224,813	168,727
Accrued vacation	470,473	474,953	364,953
Accrued bonuses	804,281	375,000	422,868
Accrued sales commissions	42,168	104,509	77,844
Current portion of deferred rent	147,771	116,681	67,085
Accrued other	102,115	129,805	37,783
Total accrued liabilities	$ 1,953,970	$ 1,425,761	$ 1,160,036

Balance Sheet Details - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accumulated depreciation					$ 77,000
Total cash proceeds from sale of fixed assets					$ 31,000
Depreciation expense	$ 223,194	$ 159,552	$ 580,366	$ 394,708

April 2014 Credit Facility - Additional Information (Detail) - USD ($)												12 Months Ended
	Sep. 20, 2018	Aug. 13, 2018	Jul. 01, 2018	Jan. 30, 2018	Dec. 08, 2017	Aug. 09, 2017	Mar. 31, 2017	Oct. 19, 2016	May 04, 2016	Apr. 30, 2014	Apr. 30, 2014	Dec. 31, 2017	Dec. 31, 2014	Jun. 30, 2018	Aug. 11, 2017	Jun. 28, 2017	Dec. 31, 2016	Jun. 30, 2016
Line of Credit Facility [Line Items]
Exercise price of unregistered warrants		$ 4.53		$ 4.53	$ 25.50	$ 45.00	$ 75.00		$ 117.00						$ 45.00
Warrant term					5 years	5 years	5 years		5 years
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value	$ 2,000,000	$ 8,400,000		$ 9,700,000	$ 100,000	$ 1,500,000	$ 2,800,000	$ 5,200,000	$ 2,000,000
Remaining outstanding principal payment												$ 1,168,811					$ 1,934,665
Maximum [Member]
Line of Credit Facility [Line Items]
Warrant issued to lender				1,095,153
Oxford Finance LLC [Member]
Line of Credit Facility [Line Items]
Additional final payment to lender												50,000
Total indebtedness and capital lease obligations outstanding																$ 3,000,000
Oxford Finance LLC [Member] \| Common Stock [Member]
Line of Credit Facility [Line Items]
Warrant issued to lender										588	588
Exercise price of unregistered warrants										$ 424.80	$ 424.80
Warrant term										10 years	10 years
Oxford Finance LLC [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Debt default limit amount										$ 250,000	$ 250,000
Debt default final judgment amount										250,000	250,000
Oxford Finance LLC [Member] \| First Term Loan [Member]
Line of Credit Facility [Line Items]
Net cash proceeds on term loan										4,898,000	4,898,000
Line of Credit Facility fees amount payable										$ 50,000	$ 50,000
Line of Credit Facility, interest rate during period										7.95%	7.95%
Percentage of final interest payment due at maturity										5.50%	5.50%
Total indebtedness and capital lease obligations outstanding																		$ 1,200,000
Issuance costs													$ 102,000
Net proceeds from credit facility													4,898,000
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value													$ 233,000
Unamortized discounts												$ 33,000					$ 78,000
Effective annual interest rate												13.87%		13.87%			13.87%
Total remaining principal payments due during fiscal year ending December 31, 2018												$ 1,201,000
Remaining outstanding principal payment														$ 175,000
Total remaining principal payment paid			$ 175,000
Oxford Finance LLC [Member] \| Two Years [Member]
Line of Credit Facility [Line Items]
Term loan prepayment fee percentage										1.00%

Equipment Financings - Additional Information (Detail)				2 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
Equipment Financings - Additional Information (Detail)	Jan. 26, 2018 USD ($) Payment	Nov. 02, 2017 USD ($)	Oct. 17, 2017 USD ($) mo	Mar. 28, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Capital Leased Assets [Line Items]
Financed equipment					$ 2,526,081		$ 2,526,081		$ 2,294,762	$ 1,559,690
Accumulated depreciation related to financed equipment					1,030,000		1,030,000		759,000	525,000
Depreciation expense related to financed equipment					223,194	$ 159,552	580,366	$ 394,708
Fixed asset purchases as equipment financings							270,000	363,000	719,000	975,000
Fixed assets with an aggregate net book value									34,000	270,000
Equipment financings with remaining outstanding balances										240,000
Total proceeds from equipment financing commitment									150,848
Machinery and equipment					2,810,226		2,810,226		2,841,388	2,728,468
Machinery and equipment, accumulated depreciation					4,721,924		$ 4,721,924		$ 4,354,097	$ 3,933,999
Equipment financings aggregate weighted average effective annual interest rate							12.53%		13.51%	13.18%
Equipment financings maturity date on outstanding arrangements range, Start							2019-02		2018-06
Equipment financings maturity date on outstanding arrangements range, End							2024-09		2024-09
Interest expense to equipment financings					63,764	88,269	$ 230,677	385,172	$ 482,623	$ 525,880
Present value of minimum lease payment due within one year					572,000		572,000		409,000
Fixed asset purchases							145,253	1,055,549	1,400,180	482,065
Subsequent Event [Member]
Capital Leased Assets [Line Items]
Fixed asset purchases	$ 250,000
Number of lease payments \| Payment	22
Lease payments per month	$ 11,081
Lease financing treasury note period	3 years
Lease agreement commencement and repayment date	Jun. 30, 2018
Equipment purchases				$ 78,000
Equipment Financings [Member]
Capital Leased Assets [Line Items]
Depreciation expense related to financed equipment					115,000	52,000	271,000	160,000	234,000	119,000
Total proceeds from equipment financing commitment		$ 151,000
Sale-leaseback transaction, aggregate gross value of fixed assets			$ 167,000
Sale-leaseback transaction, net book value of fixed assets			$ 162,000
Sale-leaseback transaction, frequency of payments			monthly
Sale-leaseback transaction, number of installments payments \| mo			36
Sale-leaseback transaction, montly installments of principal and interest payments			$ 4,884
Sale-leaseback transaction, total amount to be repaid			$ 176,000
Sale-leaseback transaction, commitment period			2020-10
Interest expense to equipment financings					$ 60,000	$ 38,000	$ 168,000	$ 118,000	171,000	$ 49,000
Machinery and Equipment [Member]
Capital Leased Assets [Line Items]
Machinery and equipment									189,000
Machinery and equipment, accumulated depreciation									155,000
Machinery and equipment, net book values									$ 34,000
Minimum [Member]
Capital Leased Assets [Line Items]
Financed equipment useful life									3 years
Minimum [Member] \| Equipment Financings [Member]
Capital Leased Assets [Line Items]
Financed equipment useful life							3 years		5 years
Maximum [Member]
Capital Leased Assets [Line Items]
Financed equipment useful life									7 years
Maximum [Member] \| Equipment Financings [Member]
Capital Leased Assets [Line Items]
Financed equipment useful life							7 years		7 years

Supplier Financings - Additional Information (Detail) - Financing Agreements With Supplier [Member] - Laboratory Software [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Financing agreement, due period	1 year
Remaining balance under financing agreement	$ 61	$ 76
Minimum [Member]
Debt Instrument [Line Items]
Interest rate	3.75%	3.75%
Maximum [Member]
Debt Instrument [Line Items]
Interest rate	5.70%	5.70%

Stock-Based Compensation - Additional Information (Detail)													3 Months Ended			9 Months Ended		12 Months Ended
	Jul. 06, 2018	Jun. 28, 2018 shares	Jul. 31, 2017 $ / shares shares	May 31, 2017 $ / shares shares	May 02, 2017 shares	Sep. 29, 2016 shares	Jul. 29, 2016 $ / shares shares	Jul. 25, 2016 $ / shares shares	Jul. 06, 2016 USD ($) $ / shares shares	Feb. 29, 2016 $ / shares shares	Aug. 31, 2015 $ / shares shares	Jun. 12, 2014 $ / shares shares	Sep. 30, 2018 USD ($) $ / shares shares	Mar. 28, 2018 shares	Sep. 30, 2017	Sep. 30, 2018 USD ($) Plan $ / shares shares	Sep. 30, 2017	Dec. 31, 2017 USD ($) Plan $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Jul. 06, 2017 shares	Dec. 31, 2015 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of equity incentive plans \| Plan																2		2
Stockholders equity reverse stock split ratio	0.03					0.33
Total Shares Outstanding													114,641			114,641		81,482	29,888		23,788
Number of Shares, Granted																58,994		58,501	9,679
Weighted average exercise price per share \| $ / shares																$ 2.96		$ 44.70	$ 75.30
Number of shares remaining forfeited																25,835		6,746	3,579
Unrecognized share-based compensation expense, weighted-average recognition period																2 years 4 months 24 days			2 years 6 months
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period																		10 years
Option awards assumptions, method used																			Black-Scholes pricing model
Weighted-average estimated fair value of options granted \| $ / shares																		$ 30.60	$ 53.70
Intrinsic value of options outstanding \| $													$ 0			$ 0		$ 0	$ 0
Intrinsic value of options exercisable \| $													0			0		0	0
Intrinsic value of options vested and unvested expected to vest \| $													0			$ 0		$ 0	$ 0
Employee Stock Option One [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Time period for vesting grants in installments on monthly basis																		monthly thereafter for the remaining three years
Employee Stock Option Two [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vesting term																		monthly vesting beginning month-one after the grant and monthly thereafter
RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period																			1 year
Weighted-average estimated fair value of options granted \| $ / shares												$ 481.50
Issuance of restricted stock units												494				0		11,666	5,527
Total RSUs forfeited																5,833		250	429
Intrinsic value shares, RSUs outstanding \| $													1,000			$ 1,000		$ 250,000
Intrinsic value amount, RSUs unvested and vested expected to vest \| $													$ 1,000			$ 1,000		$ 129,000
Weighted-average estimated fair value of options granted \| $ / shares													$ 415.80			$ 415.80		$ 56.10	$ 80.40		$ 453.60
RSUs outstanding													360			360		12,026	5,808		858
RSUs [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of vested shares issued																			148.30
Total RSUs forfeited																			346
Stock Options and RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized share-based compensation expense, stock options \| $													$ 900,474			$ 900,474		$ 1,586,000
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Estimated forfeitures rate													8.00%		8.00%	8.00%	8.00%	8.00%	8.00%
Maximum [Member] \| Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period																		4 years
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Estimated forfeitures rate													0.00%		0.00%	0.00%	0.00%	0.00%	0.00%
Options Vesting on One Year Anniversary [Member] \| Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of Overall Stock Grant Subject to Vesting																		25.00%
2013 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized													59,511			59,511
Stockholders equity reverse stock split ratio						0.33
2013 Equity Incentive Plan [Member] \| Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average exercise price per share \| $ / shares								$ 58.50
Number of shares remaining forfeited																		565
2013 Equity Incentive Plan [Member] \| Stock Options [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average estimated fair value of options granted \| $ / shares										$ 86.10	$ 132.00
Number of Shares, Granted										1,111	1,111
Weighted average exercise price per share \| $ / shares										$ 120.60	$ 180.90
Number of shares remaining forfeited																		1,677
2013 Equity Incentive Plan [Member] \| Performance Stock Options granted on August 31, 2015 [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vested																		211
2013 Equity Incentive Plan [Member] \| Performance Stock Options Granted on February 29, 2016 [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vested																		333
2013 Equity Incentive Plan [Member] \| Performance Stock Options Granted on July 29 2016 [Member] \| Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vested																		546
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member}
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average estimated fair value of options granted \| $ / shares			$ 24.90	$ 29.70
Weighted average exercise price per share \| $ / shares			$ 41.70	$ 45.00
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member} \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted				6,666
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member} \| Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted				3,333
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member} \| Employees and Executive Officers [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized					18,333
Stock options vested																0
Number of shares remaining forfeited																20,750
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member} \| Employees and Executive Officers [Member] \| Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options vested														0
Number of shares remaining forfeited														20,750
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member} \| Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized																				2,500
Number of Shares, Granted			2,500
Number of shares remaining forfeited																		83
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member} \| Chief Scientific Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted				2,500
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member} \| Senior Medical Director [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted				2,500
2013 Equity Incentive Plan [Member] \| RSUs [Member] \| Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period								1 year
Percentage of Overall Stock Grant Subject to Vesting								100.00%
Restricted stock units, grant date fair value \| $ / shares								$ 58.50
Restricted stock unit award, shares								833
2013 Equity Incentive Plan [Member] \| Retention RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period									1 year
Restricted stock units, grant date fair value \| $ / shares									$ 55.80
Restricted stock units, grant date fair value \| $									$ 108,000
2013 Equity Incentive Plan [Member] \| Retention RSUs [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units									833
2013 Equity Incentive Plan [Member] \| Retention RSUs [Member] \| Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units									1,944
2013 Equity Incentive Plan [Member] \| Time-Based RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period																1 year		1 year
Weighted-average estimated fair value of options granted \| $ / shares				$ 45.00
2013 Equity Incentive Plan [Member] \| Time-Based RSUs [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units				1,666
2013 Equity Incentive Plan [Member] \| Time-Based RSUs [Member] \| Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units				833
2013 Equity Incentive Plan [Member] \| Time-Based RSUs [Member] \| Chief Scientific Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units					833
2013 Equity Incentive Plan [Member] \| Time-Based RSUs [Member] \| Senior Medical Director [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units					833
2013 Equity Incentive Plan [Member] \| Time-Based RSUs [Member] \| Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized					5,833
2013 Equity Incentive Plan [Member] \| Time-Based RSUs [Member] \| Other Executive Officers [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units				833
2013 Equity Incentive Plan [Member] \| Performance RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average estimated fair value of options granted \| $ / shares				$ 45.00
2013 Equity Incentive Plan [Member] \| Performance RSUs [Member] \| Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units				833
2013 Equity Incentive Plan [Member] \| Performance RSUs [Member] \| Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units				833
2013 Equity Incentive Plan [Member] \| Performance RSUs [Member] \| Chief Scientific Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units					833
2013 Equity Incentive Plan [Member] \| Performance RSUs [Member] \| Senior Medical Director [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units					833
2013 Equity Incentive Plan [Member] \| Performance RSUs [Member] \| Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares authorized					5,833
2013 Equity Incentive Plan [Member] \| Performance RSUs [Member] \| Other Executive Officers [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of restricted stock units				833
2013 Equity Incentive Plan [Member] \| Performance RSU Granted on May 31, 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of vested shares issued																0
Total RSUs forfeited																1,666
2013 Equity Incentive Plan [Member] \| Performance RSU Granted on May 31, 2017 [Member] \| Subsequent Event [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of vested shares issued														0
Total RSUs forfeited														5,833
2013 Equity Incentive Plan [Member] \| Non-inducement Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized													264,098			264,098		117,431
Increase in number of shares of common stock authorized for issuance		146,666			83,333
Stock options and RSUs issued																69,449		94,982
Total Shares Outstanding													57,863			57,863		89,238
Common stock, shares authorized													194,649			194,649		22,499
2013 Equity Incentive Plan [Member] \| Non-inducement Shares [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized						102,295
2013 Equity Incentive Plan [Member] \| Non-inducement Shares [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized						34,098
2013 Equity Incentive Plan [Member] \| Inducement shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized																		11,111
Stock options and RSUs issued																60,268		5,268
Total Shares Outstanding													59,434			59,434		4,434
Common stock, shares authorized													0			0		45,842
2013 Equity Incentive Plan [Member] \| Inducement shares [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized						33,333
2013 Equity Incentive Plan [Member] \| Inducement shares [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized						11,111
2013 Equity Incentive Plan [Member] \| Options Vesting on One Year Anniversary [Member] \| Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized								2,222
Vesting period								1 year
Percentage of Overall Stock Grant Subject to Vesting								25.00%
Weighted-average estimated fair value of options granted \| $ / shares								$ 43.50
Stock option units remaining vesting period on Equal monthly basis								3 years
2013 Equity Incentive Plan [Member] \| Options Vesting on Performance Achievement [Member] \| Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized							1,111
Weighted-average estimated fair value of options granted \| $ / shares							$ 37.80
2013 Equity Incentive Plan [Member] \| Pre-reverse Stock Split [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized								33,333
2013 Equity Incentive Plan [Member] \| Post-reverse Stock Split [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized								11,111

Stock-Based Compensation - Effects of Stock-Based Compensation Related to Equity Awards to Employees and Nonemployees on Statement of Operations (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 112,999	$ 331,977	$ 447,504	$ 883,672	$ 929,822	$ 1,452,827
Stock Options [Member] \| Cost of revenues [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	10,150	59,720	37,150	133,105	142,400	115,266
Stock Options [Member] \| Research and Development Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	30,247	53,405	103,267	121,834	143,300	123,330
Stock Options [Member] \| General and Administrative Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	57,162	178,671	243,593	528,406	575,741	1,071,490
Stock Options [Member] \| Sales and Marketing Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	15,440	40,181	63,494	100,327	68,381	142,741
RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 112,999	475,688	511,929	1,232,149	1,247,481	1,593,947
RSUs [Member] \| Cost of revenues [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		20,417	(18,802)	58,717	48,745	32,338
RSUs [Member] \| Research and Development Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		20,418	13,576	57,490	55,941	30,261
RSUs [Member] \| General and Administrative Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		74,521	54,303	160,927	160,937	38,274
RSUs [Member] \| Sales and Marketing Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation		$ 28,355	$ 15,348	$ 71,343	$ 52,036	$ 40,247

Common Stock Warrants Outstanding - Summary of Equity-Classified Common Stock Warrant Activity, for Warrants Other than Underlying Unexercised Overallotment Option Warrants (Detail) - Warrants [Member] - $ / shares		9 Months Ended	12 Months Ended
	Dec. 08, 2017	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class Of Warrant Or Right [Line Items]
Number of Shares, Outstanding, Beginning Balance		288,196	387,465	26,140
Number of Shares, Issued	8,208	4,406,731	128,029	363,021
Number of Shares, Exercised			(227,228)
Number of Shares, Expired				(1,696)
Number of Shares, Outstanding, Ending Balance		4,814,927	288,196	387,465	26,140
Weighted Average Exercise Price Per Share, Outstanding, Beginning Balance		$ 78.86	$ 57.90	$ 335.40
Weighted Average Exercise Price Per Share, Issued		3.95	60.60	42.00
Weighted Average Exercise Price Per Share, Exercised			33.00
Weighted Average Exercise Price Per Share, Expired				900.00
Weighted Average Exercise Price Per Share, Outstanding, Ending Balance		$ 5.44	$ 78.86	$ 57.90	$ 335.40
Average Remaining Contractual Term (in years)		4 years 8 months 12 days	4 years	4 years 7 months 6 days	3 years 9 months 18 days
Scenario, Previously Reported [Member]
Class Of Warrant Or Right [Line Items]
Number of Shares, Outstanding, Beginning Balance		288,266
Number of Shares, Outstanding, Ending Balance			288,266
Weighted Average Exercise Price Per Share, Outstanding, Beginning Balance		$ 78.90
Weighted Average Exercise Price Per Share, Outstanding, Ending Balance			$ 78.90

Common Stock Warrants Outstanding - Equity-Classified Common Stock Warrants, Outstanding (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2018	Aug. 13, 2018	Jan. 30, 2018	Dec. 08, 2017	Aug. 11, 2017	Aug. 09, 2017	Mar. 31, 2017	Dec. 31, 2016	May 04, 2016	Dec. 31, 2015
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants			$ 4.53	$ 4.53	$ 25.50	$ 45.00	$ 45.00	$ 75.00		$ 117.00
Warrants [Member]
Class Of Warrant Or Right [Line Items]
Total Shares Outstanding	288,196	4,814,927							387,465		26,140
Weighted Average Exercise Price 0.85 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants	$ 25.50
Total Shares Outstanding	8,208
Weighted Average Contractual Life (in years)	4 years 10 months 24 days
Weighted Average Exercise Price 1.10 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants	$ 33.00
Total Shares Outstanding	97,009
Weighted Average Contractual Life (in years)	3 years 9 months 18 days
Weighted Average Exercise Price 1.50 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants	$ 45.00
Total Shares Outstanding	47,821
Weighted Average Contractual Life (in years)	4 years 7 months 6 days
Weighted Average Exercise Price 2.50 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants	$ 75.00
Total Shares Outstanding	72,000
Weighted Average Contractual Life (in years)	4 years 8 months 12 days
Weighted Average Exercise Price 3.90 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants	$ 117.00
Total Shares Outstanding	38,784
Weighted Average Contractual Life (in years)	3 years 3 months 18 days
Weighted Average Exercise Price 4.68 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants	$ 140.40
Total Shares Outstanding	19,371
Weighted Average Contractual Life (in years)	2 years 1 month 6 days
Weighted Average Exercise Price 29.72 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants	$ 891.60
Total Shares Outstanding	5,071
Weighted Average Contractual Life (in years)	1 year 8 months 12 days

Common Stock Warrants Outstanding - Additional Information (Detail) - USD ($)				9 Months Ended	12 Months Ended
	Aug. 13, 2018	Jan. 30, 2018	Dec. 08, 2017	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 11, 2017	Aug. 09, 2017	Mar. 31, 2017	May 04, 2016
Class Of Warrant Or Right [Line Items]
Class of warrant or rights, first exercisable date			Jun. 05, 2018
Class of warrant or rights, expiration date			Dec. 05, 2022
Common stock warrants outstanding, intrinsic value					$ 0
Exercise price of unregistered warrants	$ 4.53	$ 4.53	$ 25.50				$ 45.00	$ 45.00	$ 75.00	$ 117.00
Class of warrant or rights, term	5 years	5 years
Maximum [Member]
Class Of Warrant Or Right [Line Items]
Issuance of warrants to purchase shares of common stock		1,095,153
Subsequent Event [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants	$ 4.53	$ 4.53
Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants issued			8,208	4,406,731	128,029	363,021
Class of warrant or rights, first exercisable date					Jun. 05, 2018
Class of warrant or rights, expiration date					Dec. 05, 2022
Warrants [Member] \| Subsequent Event [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of unregistered warrants		$ 15.00
Class of warrant or rights, term		5 years
Warrants [Member] \| Subsequent Event [Member] \| Maximum [Member]
Class Of Warrant Or Right [Line Items]
Issuance of warrants to purchase shares of common stock		1,095,153

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Corporate tax rate		35.00%
Decrease in net deferred tax assets		$ 2,600,000
Deferred tax benefit or expense		$ 0
Percent of uncertain income tax positions recognized		50.00%	50.00%
Liability for unrecognized tax benefits		$ 0	$ 0
Percentage of change in ownership		50.00%
Period of change in ownership		3 years
Federal [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards		$ 13,600,000
Net operating loss carryforwards, expiration year		expiring beginning in 2035
Federal [Member] \| Research Tax Credit Carryforward [Member]
Income Tax Contingency [Line Items]
Research and development tax credits		$ 5,000
Income tax research and development expiration year		begin to expire in 2035
California [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards		$ 15,000,000
Net operating loss carryforwards, expiration year		expiring beginning in 2023
California [Member] \| Research Tax Credit Carryforward [Member]
Income Tax Contingency [Line Items]
Research and development tax credits		$ 3,395,000
Scenario, Plan [Member]
Income Tax Contingency [Line Items]
Corporate tax rate	21.00%

Income Taxes - Schedule of Provision for Income Taxes (Detail) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Current:
State				$ 7,624	$ 2,053
Total				7,624	2,053
Deferred
Provision for income tax	$ 2,877	$ 739	$ 5,023	$ 7,624	$ 2,053

Income Taxes - Reconciles of Income Taxes Computed at Federal Statutory Rate and Provision for Income Taxes (Detail) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income tax at statutory rate				$ (7,346,079)	$ (6,255,072)
Change in federal tax rate				2,621,803
State liability				(411,853)	(260,835)
Permanent items				214,313	67,151
Stock compensation				72,696	157,250
Nondeductible interest				15,568	21,548
Expiration of net operating losses				922,307
Research and development credit				(200,379)	(170,950)
State rate change				(18,026)	44,421
Estimated section 382 limitation				1,491,942	9,256,295
Return to provision				365,263
Other				488,264	96,406
Valuation allowance				1,791,805	(2,954,161)
Provision for income tax	$ 2,877	$ 739	$ 5,023	$ 7,624	$ 2,053

Income Taxes - Summary of Deferred Tax Assets (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Estimated net operating loss carryforward	$ 3,355,180	$ 2,218,618
Estimated research and development credits	2,686,666	2,244,047
Accruals and other	2,560,417	2,273,838
Deferred rent	90,866	164,821
Gross deferred tax assets	8,693,129	6,901,324
Less valuation allowance	$ (8,693,129)	$ (6,901,324)

Related Party Transactions - Additional Information (Detail)							3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 20, 2018 USD ($) shares	Aug. 13, 2018 USD ($)	Aug. 11, 2017 USD ($)	Feb. 01, 2017	Oct. 31, 2016 USD ($) Director Consultant shares	May 04, 2016 USD ($) Director shares	Sep. 30, 2018 USD ($) ft²	Mar. 31, 2015	Sep. 30, 2018 USD ($) ft²	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) ft²	Dec. 31, 2016 USD ($)	Nov. 30, 2011 ft²
Related Party Transaction [Line Items]
Shares issued in offering \| shares	642,438
Proceeds from issuance of common stock	$ 2,500,000	$ 11,600,000	$ 2,200,000
Number of consultants \| Consultant					1
Lease expiration date											Jul. 31, 2020
Rental income											$ 51,216	$ 153,648
San Diego California Facility [Member]
Related Party Transaction [Line Items]
Leased facility, expansion of original premises \| ft²													9,849
Lease expiration date				Mar. 31, 2017							Oct. 31, 2018
Rental income							$ 0		$ 0	$ 51,000	$ 51,000	154,000
Director [Member]
Related Party Transaction [Line Items]
Number of members of board of directors \| Director					3	3
Shares issued in offering \| shares					17,802	1,944
Issuance of warrants to purchase shares of common stock \| shares					17,802	1,361
Proceeds from issuance of common stock					$ 587,000	$ 175,000
Director [Member] \| Chief Executive Officer [Member]
Related Party Transaction [Line Items]
Number of members of board of directors \| Director					7
Claire K.T. Reiss [Member]
Related Party Transaction [Line Items]
Shares issued in offering \| shares					7,575	6,825
Issuance of warrants to purchase shares of common stock \| shares					7,575	4,777
Proceeds from issuance of common stock					$ 250,000	$ 614,273
Beneficial owner percentage of company's common stock					10.00%	10.00%
Consultants [Member]
Related Party Transaction [Line Items]
Shares issued in offering \| shares					2,636
Issuance of warrants to purchase shares of common stock \| shares					2,636
Proceeds from issuance of common stock					$ 87,000
Aegea Biotechnologies, Inc [Member]
Related Party Transaction [Line Items]
Reimbursement for shared patent costs							$ 0		$ 19,000		$ 15,000	$ 19,000
Nonexecutive [Member] \| San Diego California Facility [Member]
Related Party Transaction [Line Items]
Leased facility, expansion of original premises \| ft²							9,849		9,849		9,849
Lease agreement date of commencement									Mar. 30, 2015		Mar. 30, 2015
Leased facility, rent expense per month									$ 12,804		$ 12,804
Lease facility, refundable security deposit amount							$ 12,804		12,804		12,804
Lease expiration date								Jul. 31, 2015
Lease agreement, amount of security deposit applied against additional rents owed									16,000		16,000
Lease agreement, amount of additional rents waived									$ 3,200		$ 3,200

Commitments and Contingencies - Additional Information (Detail)		1 Months Ended	9 Months Ended	12 Months Ended
	Feb. 01, 2017	Feb. 29, 2016 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2012	Nov. 30, 2011 ft²
Loss Contingencies [Line Items]
Lease expiration date				Jul. 31, 2020
Total rent expense				$ 1,272,000	$ 1,272,000
Unconditional purchase commitment aggregate amount		$ 1,062,500	$ 404,000	$ 611,000
Unconditional purchase commitment payment terms			Quarterly	Quarterly
Unconditional purchase commitment period			May 31, 2020	May 31, 2020
Total expense for sales tax and maintenance obligations				$ 79,000	$ 32,000
Sales tax and maintenance obligations incurred but not paid				46,000
Total payments for future sales tax and maintenance obligations			$ 333,974	$ 309,000
Minimum [Member]
Loss Contingencies [Line Items]
Unconditional purchase commitment, quarterly payment amount		$ 62,500
San Diego California Facility [Member]
Loss Contingencies [Line Items]
Initial lease term						8 years
Lease expiration date	Mar. 31, 2017			Oct. 31, 2018
Leased facility, expansion of original premises \| ft²							9,849

Commitments and Contingencies - Schedule of Future Minimum Lease Payments (Detail)	Dec. 31, 2017 USD ($)
Commitments And Contingencies Disclosure [Abstract]
2018	$ 1,388,705
2019	1,430,366
2020	855,136
Total	$ 3,674,207

Selected Quarterly Financial Data - Summary of Selected Quarterly Financial Data (Detail) - USD ($)	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Balance sheet data:
Cash	$ 8,956,200	$ 2,146,611	$ 5,879,025	$ 10,000,155	$ 14,042,388	$ 4,609,332	$ 678,855	$ 3,751,570	$ 4,572,750	$ 8,956,200	$ 5,879,025	$ 2,146,611	$ 4,609,332	$ 8,821,329
Total assets	14,551,892	7,378,906	11,120,215	14,653,193	17,933,413	7,578,326	3,282,549	6,303,153	6,780,830	14,551,892	11,120,215	7,378,906	7,578,326
Total non-current liabilities		1,421,527	1,255,939	1,561,520	2,062,544	2,526,113	2,793,258	3,134,593	3,132,372		1,255,939	1,421,527	2,526,113
Total shareholders’ equity	8,938,408	1,296,034	4,026,079	7,342,257	10,418,069	658,661	(4,556,158)	(419,402)	(489,231)	8,938,408	4,026,079	1,296,034	658,661	$ 3,692,735
Statement of operations and comprehensive loss data:
Net revenues	761,591	995,226	1,111,411	1,278,961	1,683,065	1,291,587	1,047,280	662,860	221,369	2,390,772	4,073,437	5,068,663	3,223,096
Cost of revenues	2,481,916	2,359,909	2,487,054	2,368,705	2,129,454	1,899,462	1,876,288	1,669,571	1,474,790	7,616,473	6,985,213	9,345,122	6,920,111
Research and development expenses	1,089,746	908,800	856,698	841,991	757,258	668,399	600,613	716,279	728,076	3,179,612	2,455,947	3,364,747	2,713,367
General and administrative expenses	1,793,720	1,650,097	1,834,771	1,798,026	1,906,635	1,636,994	1,918,543	1,517,664	1,487,224	5,441,354	5,539,432	7,189,529	6,560,425
Sales and marketing expenses	1,404,192	1,642,941	1,675,852	1,746,867	1,278,311	1,179,167	1,278,455	1,291,709	1,304,899	4,473,908	4,701,030	6,343,971	5,054,230
Loss from operations	(6,007,983)	(5,566,521)	(5,742,964)	(5,476,628)	(4,388,593)	(4,092,435)	(4,626,619)	(4,532,363)	(4,773,620)	(18,320,575)	(15,608,185)	(21,174,706)	(18,025,037)
Net loss	$ (6,047,784)	$ (5,666,573)	$ (5,821,306)	$ (5,693,151)	$ (4,432,707)	$ (4,186,874)	$ (4,743,076)	$ (4,594,174)	$ (4,875,198)	$ (18,558,028)	$ (15,947,164)	$ (21,613,737)	$ (18,399,322)
Earnings Per Share [Abstract]
Basic	$ (2.42)	$ (5.40)	$ (6.00)	$ (6.32)	$ (6.27)	$ (8.04)	$ (16.99)	$ (17.89)	$ (22.27)	$ (8.26)	$ (18.53)	$ (23.80)	$ (57.63)
Diluted	$ (2.42)	$ (5.40)	$ (6.00)	$ (6.32)	$ (6.27)	$ (8.04)	$ (16.99)	$ (17.89)	$ (22.27)	$ (8.27)	$ (18.53)	$ (23.80)	$ (57.63)
Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic	2,767,440	1,058,055	995,254	901,007	707,389	520,668	279,023	256,742	218,900	2,322,749	860,539	908,209	19,276
Diluted	2,759,614	1,058,055	995,254	901,007	707,389	520,668	279,023	256,742	218,900	2,320,111	860,539	908,209	19,276
Scenario, Previously Reported [Member]
Earnings Per Share [Abstract]
Basic			$ (5.90)
Diluted			$ (5.90)
Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic			986,865
Diluted			986,865

Subsequent Events - Additional Information (Detail)													2 Months Ended	9 Months Ended		12 Months Ended
Subsequent Events - Additional Information (Detail)	Sep. 20, 2018 USD ($) $ / shares	Aug. 13, 2018 USD ($) $ / shares	Jan. 31, 2018 USD ($)	Jan. 30, 2018 USD ($) $ / shares shares	Jan. 30, 2018 USD ($) $ / shares shares	Jan. 26, 2018 USD ($) Payment	Dec. 08, 2017 $ / shares	Aug. 11, 2017 USD ($) $ / shares	Aug. 09, 2017 USD ($) $ / shares	Mar. 31, 2017 $ / shares	Oct. 19, 2016 USD ($)	May 04, 2016 $ / shares	Mar. 28, 2018 USD ($)	Sep. 30, 2018 USD ($) shares	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Jul. 06, 2018 shares	Sep. 27, 2016 shares
Subsequent Event [Line Items]
Fixed asset purchases														$ 145,253	$ 1,055,549	$ 1,400,180	$ 482,065
Proceeds from issuance of common stock, net of issuance costs	$ 2,200,000								$ 2,000,000		$ 9,000,000
Beginning stock price \| $ / shares	$ 3.285			$ 13.50	$ 13.50
Exercise price of unregistered warrants \| $ / shares		$ 4.53		$ 4.53	$ 4.53		$ 25.50	$ 45.00	$ 45.00	$ 75.00		$ 117.00
Class of warrant or rights, term		5 years			5 years
Proceeds from exercise of common stock warrants		$ 0						$ 0			$ 564			$ 0	$ 7,498,535	$ 7,498,535
Unregistered warrants to purchase common stock, period							5 years		5 years	5 years		5 years
Common stock, shares authorized \| shares														150,000,000		150,000,000	150,000,000	150,000,000
Maximum [Member]
Subsequent Event [Line Items]
Issuance of warrants to purchase shares of common stock \| shares				1,095,153	1,095,153
Common stock, shares authorized \| shares																			150,000,000
Minimum [Member]
Subsequent Event [Line Items]
Common stock, shares authorized \| shares																			40,000,000
Follow-on Public Offering [Member]
Subsequent Event [Line Items]
Proceeds from issuance of common stock, net of issuance costs					$ 13,300,000
Private offering, number of common stock and warrants issued \| shares					1,095,153
Beginning stock price \| $ / shares				$ 13.50	$ 13.50
Exercise price of unregistered warrants \| $ / shares	$ 3.16	$ 4.53		$ 4.53	$ 4.53
Class of warrant or rights, term	5 years	5 years			5 years
Proceeds from exercise of common stock warrants			$ 0		$ 0
Follow-on Public Offering [Member] \| Maximum [Member]
Subsequent Event [Line Items]
Issuance of warrants to purchase shares of common stock \| shares				1,095,153	1,095,153
Subsequent Event [Member]
Subsequent Event [Line Items]
Fixed asset purchases						$ 250,000
Number of lease payments \| Payment						22
Lease payments per month						$ 11,081
Lease agreements initial terms						3 years
Equipment purchases													$ 78,000
Beginning stock price \| $ / shares	$ 3.285
Exercise price of unregistered warrants \| $ / shares		$ 4.53		$ 4.53	$ 4.53
Unregistered warrants to purchase common stock, period		5 years
Subsequent Event [Member] \| Follow-on Public Offering [Member]
Subsequent Event [Line Items]
Proceeds from issuance of common stock, net of issuance costs				$ 13,300,000	$ 13,300,000
Private offering, number of common stock and warrants issued \| shares				1,095,153	1,095,153
Beginning stock price \| $ / shares				$ 13.50	$ 13.50
Exercise price of unregistered warrants \| $ / shares				$ 15.00	$ 15.00
Class of warrant or rights, term					5 years
Proceeds from exercise of common stock warrants			$ 0		$ 0
Unregistered warrants to purchase common stock, period				5 years
Subsequent Event [Member] \| Follow-on Public Offering [Member] \| Maximum [Member]
Subsequent Event [Line Items]
Issuance of warrants to purchase shares of common stock \| shares				1,095,153	1,095,153

Event (Unaudited) Subsequent to the Date of the Independent Auditor's Report (Detail) - USD ($)	Jan. 18, 2019	Sep. 20, 2018	Aug. 13, 2018	Jan. 30, 2018	Dec. 08, 2017	Aug. 09, 2017	Mar. 31, 2017	Oct. 19, 2016	May 04, 2016	Aug. 11, 2017
Proceeds from issuance of common stock, net of issuance costs		$ 2,200,000				$ 2,000,000		$ 9,000,000
Beginning stock price		$ 3.285		$ 13.50
Exercise price of unregistered warrants			$ 4.53	$ 4.53	$ 25.50	$ 45.00	$ 75.00		$ 117.00	$ 45.00
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value		$ 2,000,000	$ 8,400,000	$ 9,700,000	$ 100,000	$ 1,500,000	$ 2,800,000	$ 5,200,000	$ 2,000,000
Unregistered warrants to purchase common stock, period					5 years	5 years	5 years		5 years
Shares issued in offering		642,438
Warrant exercisable for share of common stock			1
Net proceeds from issuance of units, net of issuance expenses		$ 2,200,000	$ 10,200,000
Class of warrant or rights, term			5 years	5 years
Warrants [Member]
Aggregate warrants sold under right offering			2,549,140
Series A Preferred Stock [Member]
Shares issued in offering			11,587
Maximum [Member]
Issuance of warrants to purchase shares of common stock				1,095,153
Private Placement [Member]
Exercise price of unregistered warrants		$ 3.16
Warrant exercisable for share of common stock		1
Class of warrant or rights, term		5 years
Subsequent Event [Member]
Beginning stock price		$ 3.285
Exercise price of unregistered warrants			$ 4.53	$ 4.53
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value			$ 8.4
Unregistered warrants to purchase common stock, period			5 years
Aggregate warrants sold under right offering			11,587
Shares issued in offering		642,438
Warrant exercisable for share of common stock			1
Net proceeds from issuance of units, net of issuance expenses		$ 2,200,000	$ 10,200,000
Subsequent Event [Member] \| Warrants [Member]
Exercise price of unregistered warrants				$ 15.00
Aggregate warrants sold under right offering			2,549,140
Class of warrant or rights, term				5 years
Subsequent Event [Member] \| Common Stock [Member]
Proceeds from issuance of common stock, net of issuance costs	$ 2,000,000
Beginning stock price	$ 2.25
Shares issued in offering	999,000
Subsequent Event [Member] \| Series A Preferred Stock [Member]
Shares issued in offering			11,587
Subsequent Event [Member] \| Pre Funded Warrant [Member]
Exercise price of unregistered warrants		$ 3.275
Change in exercise price of warrants		$ 0.01
Subsequent Event [Member] \| Maximum [Member] \| Warrants [Member]
Issuance of warrants to purchase shares of common stock				1,095,153
Subsequent Event [Member] \| Maximum [Member] \| Pre Funded Warrant [Member]
Issuance of warrants to purchase shares of common stock		120,000
Subsequent Event [Member] \| Private Placement [Member]
Exercise price of unregistered warrants		$ 3.16
Warrant exercisable for share of common stock		1
Class of warrant or rights, term		5 years

Fair Value Measurement - Assumptions Used for Determining Fair Values of Common Stock Warrants (Detail)	Sep. 30, 2018 $ / shares	Sep. 20, 2018 $ / shares	Jan. 30, 2018 $ / shares	Dec. 08, 2017 $ / shares	Aug. 09, 2017 $ / shares	Mar. 31, 2017 $ / shares	Oct. 19, 2016 $ / shares	May 31, 2016 $ / shares	May 04, 2016 $ / shares
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price		$ 3.285	$ 13.50
Warrants [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price				15.60	30.90	39.30	17.10		51.60
May 2016 Public Offering [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price								$ 81.00
Expected life (in years)								5 years
May 2016 Public Offering [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price								117.00
May 2016 Public Offering [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price								0.0000
May 2016 Public Offering [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price								0.0123
May 2016 Public Offering [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price								0.900
Public Offering October 19,2016 [Member] \| Over-allotment Options [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price							$ 27.90
Expected life (in years)							30 days
Public Offering October 19,2016 [Member] \| Over-allotment Options [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price							30.993
Public Offering October 19,2016 [Member] \| Over-allotment Options [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price							0.0000
Public Offering October 19,2016 [Member] \| Over-allotment Options [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price							0.0025
Public Offering October 19,2016 [Member] \| Over-allotment Options [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price							0.129
Public Offering October 19,2016 [Member] \| Warrants [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price							$ 27.90
Expected life (in years)							5 years
Public Offering October 19,2016 [Member] \| Warrants [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price							33.00
Public Offering October 19,2016 [Member] \| Warrants [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price							0.0000
Public Offering October 19,2016 [Member] \| Warrants [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price							0.0124
Public Offering October 19,2016 [Member] \| Warrants [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price							0.800
March 31, 2017 Offering [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price						$ 63.90
Expected life (in years)						5 years
March 31, 2017 Offering [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price						75.00
March 31, 2017 Offering [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price						0.0000
March 31, 2017 Offering [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price						0.0193
March 31, 2017 Offering [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price						0.800
August 9, 2017 Offering [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price					$ 41.70
Expected life (in years)					5 years
August 9, 2017 Offering [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price					45.00
August 9, 2017 Offering [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price					0.0000
August 9, 2017 Offering [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price					0.0181
August 9, 2017 Offering [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price					1.000
December 8, 2017 Offering [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price				$ 22.197
Expected life (in years)				4 years 6 months
December 8, 2017 Offering [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price				25.50
December 8, 2017 Offering [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price				0.0000
December 8, 2017 Offering [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price				0.0209
December 8, 2017 Offering [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price				1.000
January 30, 2018 Offering [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price	$ 10.17
January 30, 2018 Offering [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	4.53
January 30, 2018 Offering [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	0.00
January 30, 2018 Offering [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	2.48
January 30, 2018 Offering [Member] \| Expected Life [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Expected life (in years)	5 years
January 30, 2018 Offering [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	99.00
August 13, 2018 Rights Offering [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price	$ 3.89
August 13, 2018 Rights Offering [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	4.53
August 13, 2018 Rights Offering [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	0.00
August 13, 2018 Rights Offering [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	2.75
August 13, 2018 Rights Offering [Member] \| Expected Life [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Expected life (in years)	5 years
August 13, 2018 Rights Offering [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	128.69
September 20, 2018 Offering [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price	$ 2.92
September 20, 2018 Offering [Member] \| Exercise Price [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	3.16
September 20, 2018 Offering [Member] \| Expected Dividend Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	0.00
September 20, 2018 Offering [Member] \| Discount Rate-Bond Equivalent Yield [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	2.77
September 20, 2018 Offering [Member] \| Expected Life [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Expected life (in years)	5 years 6 months
September 20, 2018 Offering [Member] \| Expected Volatility [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Exercise price	130.7

401(k) Plan - Additional Information (Detail) - USD ($)	12 Months Ended
401(k) Plan - Additional Information (Detail) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Postemployment Benefits [Abstract]
Employer's matching contributions to 401(k) plan	$ 90,000	$ 0