Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2018	May 11, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Trading Symbol	BIOC
Entity Registrant Name	BIOCEPT INC
Entity Central Index Key	0001044378
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		68,213,349

Condensed Balance Sheets - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash	$ 9,272,420	$ 2,146,611
Accounts receivable, net	1,329,701	1,193,426
Inventories, net	490,979	498,702
Prepaid expenses and other current assets	665,140	416,600
Total current assets	11,758,240	4,255,339
Fixed assets, net	2,989,587	3,123,567
Total assets	14,747,827	7,378,906
Current liabilities:
Accounts payable	1,387,222	1,269,953
Accrued liabilities	2,271,269	1,752,363
Supplier financings	69,995	61,226
Current portion of equipment financings	475,507	408,992
Credit facility, net	678,927	1,168,811
Total current liabilities	4,882,920	4,661,345
Non-current portion of equipment financings	1,123,536	1,150,063
Non-current portion of deferred rent	233,657	271,464
Total liabilities	6,240,113	6,082,872
Commitments and contingencies (see Note 11)
Shareholders’ equity:
Preferred stock, $0.0001 par value, 5,000,000 authorized; no shares issued and outstanding at December 31, 2017 and March 31, 2018.
Common stock, $0.0001 par value, 150,000,000 authorized; 35,183,743 issued and outstanding at December 31, 2017; 68,038,349 issued and outstanding at March 31, 2018.	6,804	3,518
Additional paid-in capital	210,106,921	196,542,123
Accumulated deficit	(201,606,011)	(195,249,607)
Total shareholders’ equity	8,507,714	1,296,034
Total liabilities and shareholders’ equity	$ 14,747,827	$ 7,378,906

Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	68,038,349	35,183,743
Common stock, shares outstanding	68,038,349	35,183,743

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Net revenues	$ 806,943	$ 1,683,065
Costs and expenses:
Cost of revenues	2,434,886	2,129,454
Research and development expenses	1,070,581	757,258
General and administrative expenses	1,938,664	1,906,635
Sales and marketing expenses	1,636,542	1,278,311
Total costs and expenses	7,080,673	6,071,658
Loss from operations	(6,273,730)	(4,388,593)
Other income/ (expense):
Interest expense	(82,674)	(82,526)
Other income		38,412
Total other income/ (expense):	(82,674)	(44,114)
Loss before income taxes	(6,356,404)	(4,432,707)
Net loss and comprehensive loss	$ (6,356,404)	$ (4,432,707)
Weighted-average shares outstanding used in computing net loss per share attributable to common shareholders:
Basic	57,086,814	20,969,131
Diluted	57,086,814	20,969,131
Net loss per common share:
Basic	$ (0.11)	$ (0.21)
Diluted	$ (0.11)	$ (0.21)

Condensed Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Flows from Operating Activities
Net loss	$ (6,356,404)	$ (4,432,707)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	179,772	116,156
Inventory reserve	(14,711)	(29,833)
Stock-based compensation	225,263	373,222
Non-cash interest expense related to credit facility and other financing activities	18,214	3,443
Increase/(decrease) in cash resulting from changes in:
Accounts receivable, net	(136,275)	(705,925)
Inventory	22,434	53,364
Prepaid expenses and other current assets	(199,677)	97,732
Accounts payable	204,171	335,972
Accrued liabilities	508,543	466,901
Deferred rent	(27,444)	(17,381)
Net cash used in operating activities	(5,576,114)	(3,739,056)
Cash Flows from Investing Activities:
Purchases of fixed assets	(53,980)	(127,223)
Net cash used in investing activities	(53,980)	(127,223)
Cash Flows from Financing Activities:
Net proceeds from issuance of common stock and warrants	13,342,821	8,559,958
Proceeds from exercise of common stock warrants	0	5,258,935
Payments on equipment financings	(38,726)	(12,534)
Payments on supplier and other third-party financings	(40,094)	(37,633)
Payments on credit facility	(508,098)	(469,391)
Net cash provided by financing activities	12,755,903	13,299,335
Net increase in Cash	7,125,809	9,433,056
Cash at Beginning of Period	2,146,611	4,609,332
Cash at End of Period	9,272,420	14,042,388
Cash paid during the period for:
Interest	$ 63,860	$ 92,651

Condensed Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($)			3 Months Ended		12 Months Ended
	Jan. 30, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Cancelled insurance premiums previously financed through third-parties, remaining principal outstanding balance			$ 31,000
Insurance premiums financed through third-parties			80,000
Fixed assets purchased under capital lease obligations			79,000	$ 181,000
Purchases of fixed assets			$ 19,000	$ 203,000	$ 31,000	$ 58,000
Issuance of unregistered warrants to purchase shares of common stock	32,854,606	2,160,000		2,160,000
Exercise price of unregistered warrants	$ 0.50	$ 2.50		$ 2.50
Unregistered warrants to purchase common stock, period		5 years
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value	$ 9,700,000	$ 2,800,000
Offering fees and costs recorded within common stock issuance costs as an offset to additional paid in capital	$ 1,400,000	$ 728,000
Public offering, number of common stock and warrants issued	32,854,606
Stock price	$ 0.45
Class of warrant or rights, term	5 years
Maximum [Member]
Issuance of warrants to purchase shares of common stock	32,854,606

The Company, Business Activities and Basis of Presentation

3 Months Ended

Mar. 31, 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.

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 months ended March 31, 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 months ended March 31, 2017 and 2018 disaggregated by source and nature are as follows:

	For the three months ended March 31,
	2017		2018
Net revenues from contracted payers*	$	661,644	$	337,946
Net revenues from non-contracted payers		960,632		424,363
Development services revenues		60,789		44,634
Total net revenues	$	1,683,065	$	806,943

*Includes Medicare and Medicare Advantage, as reimbursement amounts are fixed.

	For the three months ended March 31,
	2017		2018
Net commercial revenues recognized upon delivery	$	725,690	$	762,309
Development services revenues recognized upon delivery		60,789		44,634
Commercial revenues recognized upon cash collection		896,586		—
Total net revenues	$	1,683,065	$	806,943

During the three months ended March 31, 2017, the Company recorded approximately $874,000 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 $0.04. 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 $726,000 and $139,000 during the three months ended March 31, 2017 and 2018, respectively, representing corresponding decreases in net loss per common share of $0.03 and zero, respectively.

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 months ended March 31, 2017 and 2018 were as follows:

	For the three months ended March 31,
	2017			2018
Medicare and Medicare Advantage		35	%		39	%
Blue Cross Blue Shield		20	%		22	%
United Healthcare		12	%		22	%

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 March 31, 2018 were as follows:

	December 31, 2017			March 31, 2018
Blue Cross Blue Shield		27	%		25	%
Medicare and Medicare Advantage		21	%		19	%
United Healthcare		15	%		18	%

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.

Liquidity and Going Concern Uncertainty	3 Months Ended
Liquidity and Going Concern Uncertainty	Mar. 31, 2018
Accounting Policies [Abstract]
Liquidity and Going Concern Uncertainty	2. Liquidity and Going Concern Uncertainty As of March 31, 2018, cash totaled $9.3 million and the Company had an accumulated deficit of $201.6 million. For the year ended December 31, 2017 and the three months ended March 31, 2018, the Company incurred net losses of $21.6 million and $6.4 million, respectively. At March 31, 2018, the Company had aggregate net interest-bearing indebtedness of $2.7 million, of which $1.6 million was due within one year, in addition to $3.3 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 $500,000 remained outstanding at March 31, 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. In May 2015, the SEC declared effective a shelf registration statement filed by the Company, which expires on May 21, 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 $3.90 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 4,320,000 shares of the Company’s common stock was effected under this registration statement at a per share price of $2.15. In a concurrent private placement, the Company sold unregistered warrants to purchase up to an aggregate of 2,160,000 shares of its common stock that closed concurrently with the offering of 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 $2.50 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 4,925,000 shares of the Company’s common stock was effected under this registration statement at a per share price of $0.68. The placement agent was issued a warrant to purchase 246,250 shares of common stock at an exercise price of $0.85 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 from 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 627,131 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 $1.10 per share until their expiration in October 2021. 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 $1.50 per share until their expiration in August 2022. 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 32,854,606 shares of its common stock and warrants to purchase up to an aggregate of 32,854,606 shares of its common stock at a combined offering price of $0.45 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 $0.50 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, 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.

Sales of Equity Securities	3 Months Ended
Sales of Equity Securities	Mar. 31, 2018
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 expires on May 21, 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 Wainwright, and a securities purchase agreement dated April 29, 2016 between the Company and the purchasers signatory thereto, a public offering of 1,662,191 shares of the Company’s common stock and warrants to purchase up to an aggregate of 1,163,526 shares of common stock was effected under this registration statement at a combined offering price of $3.00. All warrants sold in this offering have a per share exercise price of $3.90, 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. The closing of the sale of these securities to the purchasers occurred on May 4, 2016, pursuant to which the Company received approximately $4.3 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. 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 $3.90 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 4,320,000 shares of the Company’s common stock was effected under this registration statement at a per share price of $2.15, which closed on March 31, 2017. In a concurrent private placement, the Company sold unregistered warrants to purchase up to an aggregate of 2,160,000 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 $2.50 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. 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 4,925,000 shares of the Company’s common stock was effected under this registration statement at a per share price of $0.68. The placement agent was issued a warrant to purchase 246,250 shares of common stock at an exercise price of $0.85 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. 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. 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 1,466,667 shares of the Company’s common stock and warrants to purchase up to an aggregate of 1,434,639 shares of common stock was effected at a combined offering price of $1.50 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 $1.50, 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. 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 from 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 from the closing of a follow-on public offering of 32,854,606 shares of its common stock and warrants to purchase up to an aggregate of 32,854,606 shares of its common stock at a combined offering price of $0.45 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. All warrants sold in this offering have an exercise price of $0.50 per share, subject to down round adjustment, are exercisable immediately and expire five years from the date of issuance. The estimated grant date fair value of these warrants of approximately $9.7 million was recorded as an offset to additional paid-in capital upon the closing of this offering (see Note 4). Subsequent to the closing of this offering, no additional cash proceeds have been received from the exercise of warrants sold in this offering.

Fair Value Measurement

3 Months Ended

Mar. 31, 2018

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 $79,000 during the three months ended March 31, 2018 were based on information provided by vendors, which involved the use of significant unobservable Level 3 inputs.

The estimated fair value of the credit facility entered into with Oxford Finance LLC in April 2014, or the April 2014 Credit Facility, at March 31, 2018 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 January 30, 2018 offering, the estimated grant date fair value of approximately $0.29 per share associated with the warrants to purchase up to 32,854,606 shares of common stock issued in this offering, or a total of approximately $9.7 million, was recorded as an offset to additional paid-in capital. All warrants sold in this offering have an exercise price of $0.50 per share, subject to down round adjustment, are exercisable immediately 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	$	0.339
Exercise price	$	0.50
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.48	%
Expected life (in years)		5.00
Expected volatility		99.0	%

- 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

3 Months Ended

Mar. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Balance Sheet Details

5. Balance Sheet Details

The following provides certain balance sheet details:

	December 31,			March 31,
	2017			2018
Fixed Assets
Machinery and equipment	$	2,841,388		$	2,763,108
Furniture and office equipment		147,976			152,964
Computer equipment and software		1,637,034			1,430,669
Leasehold improvements		553,529			557,020
Financed equipment		2,294,762			2,373,475
Construction in process		2,975			28,563
Total fixed assets, gross		7,477,664			7,305,799
Less accumulated depreciation and amortization		(4,354,097	)		(4,316,212	)
Total fixed assets, net	$	3,123,567		$	2,989,587
Accrued Liabilities
Accrued interest	$	326,602		$	327,203
Accrued payroll		224,813			438,460
Accrued vacation		474,953			544,614
Accrued bonuses		375,000			675,254
Accrued sales commissions		104,509			65,717
Current portion of deferred rent		116,681			127,044
Accrued other		129,805			92,977
Total accrued liabilities	$	1,752,363		$	2,271,269

During the three months ended March 31, 2018, non-financed equipment fixed assets with aggregate gross book values and corresponding accumulated depreciation amounts of approximately $209,000 were disposed of.

April 2014 Credit Facility	3 Months Ended
April 2014 Credit Facility	Mar. 31, 2018
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 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 17,655 shares of the Company’s common stock at an exercise price of $14.16 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 $33,000 and $14,000 remaining at December 31, 2017 and March 31, 2018, respectively. The effective annual interest rate associated with the April 2014 Credit Facility was 13.87% at both December 31, 2017 and March 31, 2018. As of March 31, 2018, total remaining principal payments of $693,000 were due under the April 2014 Credit Facility.

Equipment Financings

3 Months Ended

Mar. 31, 2018

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 $2,374,000 at December 31, 2017 and March 31, 2018, respectively. Total accumulated depreciation related to financed equipment was approximately $759,000 and $826,000 at December 31, 2017 and March 31, 2018, respectively, and total depreciation expense related to financed equipment during the three months ended March 31, 2017 and 2018 was approximately $55,000 and $67,000, respectively.

On January 26, 2018, the Company executed an agreement with a third-party lender to finance $240,000 of planned fixed asset purchases and an anticipated $10,000 of corresponding maintenance obligations. Under the terms of the lease agreement, upon lease commencement and repayment, which occurs once the Company has financed $240,000 of equipment purchases under the lease agreement, the Company is required to make 22 payments of $11,081 per month thereafter, subject to adjustment in the event of an increase in the 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 agreement. 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 $98,000 of equipment purchases and $5,000 of corresponding maintenance obligations had been financed under this agreement.

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 March 31, 2018:

				Maintenance
	Minimum			and Sales Tax
	Lease			Obligation
	Payments			Payments
2018	$	394,959		$	66,456
2019		505,077			80,200
2020		419,817			64,163
2021		303,228			53,252
2022		260,462			56,005
Thereafter		262,950			40,641
Total payments		2,146,493			360,717
Less amount representing interest		(547,450	)		—
Present value of payments	$	1,599,043		$	360,717

The aggregate weighted average effective annual interest rate associated with equipment financings was 13.51% and 12.38% at December 31, 2017 and March 31, 2018, respectively, and the maturity dates on such outstanding arrangements range from June 2018 to September 2024. During the three months ended March 31, 2017 and 2018, total interest expense related to equipment financings of $38,000 and $43,000, respectively, was recorded to the Company’s unaudited condensed statement of operations and comprehensive loss. At March 31, 2018, the present value of minimum lease payments due within one year was approximately $476,000.

Stock-Based Compensation

3 Months Ended

Mar. 31, 2018

Disclosure Of Compensation Related Costs Sharebased 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. As of March 31, 2018, 333,333 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 March 31, 2018, under all plans, a total of 3,522,955 non-inducement shares were authorized for issuance, 2,033,009 shares had been issued with 1,860,698 non-inducement stock options and restricted stock units, or RSUs, underlying outstanding awards, and 1,489,946 non-inducement shares were available for grant. As of March 31, 2018, a total of 333,333 inducement shares were authorized for issuance, 158,049 inducement shares had been issued with 133,049 inducement stock options and RSUs underlying outstanding awards, and 175,284 inducement shares were available for grant under the 2013 Plan.

Stock Options

A summary of stock option activity for the three months ended March 31, 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		2,449,284		$	3.79		8.8
Granted		—			—
Exercised		—			—
Cancelled/forfeited/expired		(641,457	)	$	1.60
Outstanding at March 31, 2018		1,807,827		$	4.57		8.4
Vested and unvested expected to vest at March 31, 2018		1,763,848		$	4.65		8.3

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

On May 2, 2017, the Company’s Board of Directors approved the issuance of an aggregate of 550,000 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 200,000 performance stock options were granted to the Company’s CEO, 100,000 performance stock options were granted to its CFO, and 75,000 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 $1.50 per share and an estimated grant date fair value of $0.99 per share. On July 6, 2017, the Company’s Compensation Committee of the Board of Directors approved the issuance of an aggregate of 75,000 performance stock options to be granted on July 31, 2017 to certain of the Company’s employees pursuant to the 2013 Plan, of which 2,500 performance stock options were forfeited by December 31, 2017. Each performance stock option granted on July 31, 2017 had an exercise price of $1.39 per share and an estimated grant date fair value of $0.83 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 three months ended March 31, 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 622,500 shares underlying the remaining outstanding performance stock option awards at December 31, 2017 were forfeited.

Restricted Stock

A summary of RSU activity for the three months ended March 31, 2018 is as follows:

				Weighted
	Number of			Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2017		360,920		$	1.87
Granted		—			—
Vested and issued		—			—
Forfeited		(175,000	)	$	1.50
Outstanding at March 31, 2018		185,920		$	2.23
Vested and unvested expected to vest at March 31, 2018		185,920		$	2.23

At March 31, 2018, the intrinsic values of RSUs outstanding and RSUs unvested and expected to vest were each approximately $55,000. Of the 185,920 RSUs outstanding at March 31, 2018, 10,920 were fully vested.

On May 2, 2017, the Company’s Board of Directors approved the issuance of an aggregate of 175,000 time-based RSUs and 175,000 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 50,000 time-based RSUs and 25,000 performance RSUs were granted to its CEO, and 25,000 time-based RSUs and 25,000 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 $1.50 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 three months ended March 31, 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 175,000 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
	March 31,
	2017		2018
Stock Options
Cost of revenues	$	31,770	$	17,579
Research and development expenses		29,256		37,147
General and administrative expenses		192,053		105,175
Sales and marketing expenses		40,540		23,265
Total expenses related to stock options		293,619		183,166
RSUs
Cost of revenues		15,167		(17,250	)
Research and development expenses		14,358		10,015
General and administrative expenses		29,933		40,059
Sales and marketing expenses		20,145		9,273
Total stock-based compensation	$	373,222	$	225,263

Stock-based compensation expense was recorded net of estimated forfeitures of 0% - 8% per annum during each of the three months ended March 31, 2017 and 2018. As of March 31, 2018, total unrecognized share-based compensation expense related to unvested stock options and RSUs, adjusted for estimated forfeitures, was approximately $1,197,000 and is expected to be recognized over a weighted-average period of approximately 2.4 years.

Common Stock Warrants Outstanding

3 Months Ended

Mar. 31, 2018

Other Liabilities Disclosure [Abstract]

Common Stock Warrants Outstanding

9. Common Stock Warrants Outstanding

A summary of equity-classified common stock warrant activity for the three months ended March 31, 2018 is as follows:

					Average
			Weighted		Remaining
	Number of		Average Exercise		Contractual
	Shares		Price Per Share		Term in Years
Outstanding at December 31, 2017		8,647,996	$	2.63		4.0
Issued		32,854,606	$	0.50
Exercised		—		—
Expired		—		—
Outstanding at March 31, 2018		41,502,602	$	0.94		4.6

Further information about equity-classified common stock warrants outstanding at March 31, 2018 is as follows:

				Weighted
Weighted				Average
Average		Total Shares		Contractual
Exercise Price		Outstanding		Life (in years)
$	0.50		32,854,606		4.8
$	0.85		246,250		4.7
$	1.10		2,910,281		3.6
$	1.50		1,434,639		4.4
$	2.50		2,160,000		4.5
$	3.90		1,163,526		3.1
$	4.68		581,153		1.9
$	29.72		152,147		1.5
			41,502,602

All warrants outstanding at March 31, 2018 are exercisable, except for the 246,250 warrants issued on December 8, 2017, which first become exercisable on June 5, 2018 and expire on December 5, 2022. The exercise price of $0.50 per share associated with the 32,854,606 warrants issued on January 30, 2018 is subject to down round adjustment. The intrinsic value of equity-classified common stock warrants outstanding at March 31, 2018 was zero.

Net Loss per Common Share

3 Months Ended

Mar. 31, 2018

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 months ended March 31, 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. Therefore, 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 months ended
	March 31,
	2017		2018
Preferred warrants outstanding (number of common stock equivalents)		529		529
Common warrants outstanding		9,003,137		41,502,602
RSUs outstanding		174,249		185,920
Common options outstanding		931,504		1,807,827
Total anti-dilutive common share equivalents		10,109,419		43,496,878

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2018
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 March 31, 2018, a balance of $500,000 remained outstanding under this purchase commitment. During the three months ended March 31, 2017 and 2018, total expense recorded in the Company’s unaudited condensed statements of operations and comprehensive loss for sales tax and maintenance obligations associated with equipment financing arrangements was approximately $18,000 and $29,000, respectively. At December 31, 2017 and March 31, 2018, approximately $46,000 and $64,000, respectively, 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 5). Future payments totaling approximately $361,000 for sales tax and maintenance obligations associated with financed equipment were due under equipment financing arrangements at March 31, 2018, which will be expensed as incurred (see Note 7).

Related Party Transactions	3 Months Ended
Related Party Transactions	Mar. 31, 2018
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 subsequent to March 31, 2018, from Aegea as reimbursements for shared patent costs under the Cross-License Agreement (see Note 13). 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 $38,000 and $51,000 in rental income was recorded to other income/(expense) in the Company’s statement of operations and comprehensive loss during the three months ended March 31, 2017 and the year ended December 31, 2017, respectively.

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	13. Subsequent Events The Company received a payment of approximately $19,000 subsequent to March 31, 2018 from Aegea as reimbursement for shared patent costs under the Cross-License Agreement (see Note 12). Subsequent to the three months ended March 31, 2018, the Company financed certain business insurance premiums totaling approximately $387,000 through third-parties.

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

3 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

The Company and Business Activities

Basis of Presentation

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

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 months ended March 31, 2017 and 2018 disaggregated by source and nature are as follows:

	For the three months ended March 31,
	2017		2018
Net revenues from contracted payers*	$	661,644	$	337,946
Net revenues from non-contracted payers		960,632		424,363
Development services revenues		60,789		44,634
Total net revenues	$	1,683,065	$	806,943

*Includes Medicare and Medicare Advantage, as reimbursement amounts are fixed.

	For the three months ended March 31,
	2017		2018
Net commercial revenues recognized upon delivery	$	725,690	$	762,309
Development services revenues recognized upon delivery		60,789		44,634
Commercial revenues recognized upon cash collection		896,586		—
Total net revenues	$	1,683,065	$	806,943

Concentration of Risk

	For the three months ended March 31,
	2017			2018
Medicare and Medicare Advantage		35	%		39	%
Blue Cross Blue Shield		20	%		22	%
United Healthcare		12	%		22	%

	December 31, 2017			March 31, 2018
Blue Cross Blue Shield		27	%		25	%
Medicare and Medicare Advantage		21	%		19	%
United Healthcare		15	%		18	%

Recent Accounting Pronouncements

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

3 Months Ended

Mar. 31, 2018

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 months ended March 31, 2017 and 2018 disaggregated by source and nature are as follows:

	For the three months ended March 31,
	2017		2018
Net revenues from contracted payers*	$	661,644	$	337,946
Net revenues from non-contracted payers		960,632		424,363
Development services revenues		60,789		44,634
Total net revenues	$	1,683,065	$	806,943

*Includes Medicare and Medicare Advantage, as reimbursement amounts are fixed.

	For the three months ended March 31,
	2017		2018
Net commercial revenues recognized upon delivery	$	725,690	$	762,309
Development services revenues recognized upon delivery		60,789		44,634
Commercial revenues recognized upon cash collection		896,586		—
Total net revenues	$	1,683,065	$	806,943

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 March 31,
	2017			2018
Medicare and Medicare Advantage		35	%		39	%
Blue Cross Blue Shield		20	%		22	%
United Healthcare		12	%		22	%

	December 31, 2017			March 31, 2018
Blue Cross Blue Shield		27	%		25	%
Medicare and Medicare Advantage		21	%		19	%
United Healthcare		15	%		18	%

Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

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	$	0.339
Exercise price	$	0.50
Expected dividend yield		0.00	%
Discount rate-bond equivalent yield		2.48	%
Expected life (in years)		5.00
Expected volatility		99.0	%

Balance Sheet Details (Tables)

3 Months Ended

Mar. 31, 2018

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Schedule of Fixed Assets and Accrued Liabilities

The following provides certain balance sheet details:

	December 31,			March 31,
	2017			2018
Fixed Assets
Machinery and equipment	$	2,841,388		$	2,763,108
Furniture and office equipment		147,976			152,964
Computer equipment and software		1,637,034			1,430,669
Leasehold improvements		553,529			557,020
Financed equipment		2,294,762			2,373,475
Construction in process		2,975			28,563
Total fixed assets, gross		7,477,664			7,305,799
Less accumulated depreciation and amortization		(4,354,097	)		(4,316,212	)
Total fixed assets, net	$	3,123,567		$	2,989,587
Accrued Liabilities
Accrued interest	$	326,602		$	327,203
Accrued payroll		224,813			438,460
Accrued vacation		474,953			544,614
Accrued bonuses		375,000			675,254
Accrued sales commissions		104,509			65,717
Current portion of deferred rent		116,681			127,044
Accrued other		129,805			92,977
Total accrued liabilities	$	1,752,363		$	2,271,269

Equipment Financings (Tables)

3 Months Ended

Mar. 31, 2018

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	$	394,959		$	66,456
2019		505,077			80,200
2020		419,817			64,163
2021		303,228			53,252
2022		260,462			56,005
Thereafter		262,950			40,641
Total payments		2,146,493			360,717
Less amount representing interest		(547,450	)		—
Present value of payments	$	1,599,043		$	360,717

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Activity

A summary of stock option activity for the three months ended March 31, 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		2,449,284		$	3.79		8.8
Granted		—			—
Exercised		—			—
Cancelled/forfeited/expired		(641,457	)	$	1.60
Outstanding at March 31, 2018		1,807,827		$	4.57		8.4
Vested and unvested expected to vest at March 31, 2018		1,763,848		$	4.65		8.3

Summary of RSU Activity

A summary of RSU activity for the three months ended March 31, 2018 is as follows:

				Weighted
	Number of			Average Grant
	Shares			Date Fair Value
Outstanding at December 31, 2017		360,920		$	1.87
Granted		—			—
Vested and issued		—			—
Forfeited		(175,000	)	$	1.50
Outstanding at March 31, 2018		185,920		$	2.23
Vested and unvested expected to vest at March 31, 2018		185,920		$	2.23

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
	March 31,
	2017		2018
Stock Options
Cost of revenues	$	31,770	$	17,579
Research and development expenses		29,256		37,147
General and administrative expenses		192,053		105,175
Sales and marketing expenses		40,540		23,265
Total expenses related to stock options		293,619		183,166
RSUs
Cost of revenues		15,167		(17,250	)
Research and development expenses		14,358		10,015
General and administrative expenses		29,933		40,059
Sales and marketing expenses		20,145		9,273
Total stock-based compensation	$	373,222	$	225,263

Common Stock Warrants Outstanding (Tables)

3 Months Ended

Mar. 31, 2018

Equity Classified Warrants [Abstract]

Summary of Equity-Classified Common Stock Warrant Activity

A summary of equity-classified common stock warrant activity for the three months ended March 31, 2018 is as follows:

					Average
			Weighted		Remaining
	Number of		Average Exercise		Contractual
	Shares		Price Per Share		Term in Years
Outstanding at December 31, 2017		8,647,996	$	2.63		4.0
Issued		32,854,606	$	0.50
Exercised		—		—
Expired		—		—
Outstanding at March 31, 2018		41,502,602	$	0.94		4.6

Schedule of Equity-Classified Common Stock Warrants, Outstanding

Further information about equity-classified common stock warrants outstanding at March 31, 2018 is as follows:

				Weighted
Weighted				Average
Average		Total Shares		Contractual
Exercise Price		Outstanding		Life (in years)
$	0.50		32,854,606		4.8
$	0.85		246,250		4.7
$	1.10		2,910,281		3.6
$	1.50		1,434,639		4.4
$	2.50		2,160,000		4.5
$	3.90		1,163,526		3.1
$	4.68		581,153		1.9
$	29.72		152,147		1.5
			41,502,602

- 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

Net Loss per Common Share (Tables)

3 Months Ended

Mar. 31, 2018

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 months ended
	March 31,
	2017		2018
Preferred warrants outstanding (number of common stock equivalents)		529		529
Common warrants outstanding		9,003,137		41,502,602
RSUs outstanding		174,249		185,920
Common options outstanding		931,504		1,807,827
Total anti-dilutive common share equivalents		10,109,419		43,496,878

The Company, Business Activities and Basis of Presentation - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
The Company Business Activities And Basis Of Presentation [Line Items]
Nonrecurring net revenue recognized on accrual basis associated with cases delivered		$ 874,000
Increase (decrease) in net income (loss) per common share on nonrecurring net revenue		$ (0.04)
Net revenue recorded in excess of commercial cash collections	$ 139,000	$ 726,000
Increase decrease in net income (loss) per common share	$ 0	$ (0.03)
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

Mar. 31, 2018

Mar. 31, 2017

Revenue Recognition [Abstract]

Net revenues from contracted payers

^[1]

$ 337,946

$ 661,644

Net revenues from non-contracted payers

424,363

960,632

Development services revenues

44,634

60,789

Total net revenues

$ 806,943

$ 1,683,065

[1]	Includes Medicare and Medicare Advantage, as reimbursement amounts are fixed.

The Company, Business Activities and Basis of Presentation - Composition of Net Revenues Recognized Disaggregated by Nature (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue Recognition [Abstract]
Net commercial revenues recognized upon delivery	$ 762,309	$ 725,690
Development services revenues recognized upon delivery	44,634	60,789
Commercial revenues recognized upon cash collection		896,586
Total net revenues	$ 806,943	$ 1,683,065

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		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Customer Concentration Risk [Member] \| Net Revenues [Member] \| Blue Cross Blue Shield [Member]
Concentration Risk [Line Items]
Concentration risk percentage	22.00%	20.00%
Customer Concentration Risk [Member] \| Net Revenues [Member] \| Medicare and Medicare Advantage [Member]
Concentration Risk [Line Items]
Concentration risk percentage	39.00%	35.00%
Customer Concentration Risk [Member] \| Net Revenues [Member] \| United Healthcare [Member]
Concentration Risk [Line Items]
Concentration risk percentage	22.00%	12.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| Blue Cross Blue Shield [Member]
Concentration Risk [Line Items]
Concentration risk percentage	25.00%		27.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| Medicare and Medicare Advantage [Member]
Concentration Risk [Line Items]
Concentration risk percentage	19.00%		21.00%
Credit Concentration Risk [Member] \| Net Accounts Receivable [Member] \| United Healthcare [Member]
Concentration Risk [Line Items]
Concentration risk percentage	18.00%		15.00%

Liquidity and Going Concern Uncertainty- Additional Information (Detail) - USD ($)									1 Months Ended		3 Months Ended		12 Months Ended
	Jan. 31, 2018	Jan. 30, 2018	Dec. 08, 2017	Aug. 11, 2017	Aug. 09, 2017	Mar. 31, 2017	Oct. 19, 2016	May 04, 2016	Feb. 29, 2016	May 31, 2015	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Liquidity And Managements Plans [Line Items]
Cash						$ 14,042,388					$ 9,272,420	$ 14,042,388	$ 2,146,611	$ 4,609,332
Accumulated deficit											(201,606,011)		(195,249,607)
Net loss											(6,356,404)	(4,432,707)	$ (21,600,000)
Aggregate net interest-bearing indebtedness											2,700,000
Aggregate net interest-bearing indebtedness due within one year											1,600,000
Other non-interest bearing current liabilities											3,300,000
Unconditional purchase commitment aggregate amount									$ 1,062,500		$ 500,000
Unconditional purchase commitment payment terms											Quarterly
Unconditional purchase commitment period											May 31, 2020
Shelf registration statement expiration period										May 21, 2018
Proceeds from issuance of common stock, net of issuance costs							$ 9,000,000
Proceeds from exercise of common stock warrants							7,500,000				$ 0	$ 5,258,935
Proceeds from gross exercise of common stock warrants outstanding											$ 3,200,000
Exercisable warrant available price per share											$ 1.10
Exercisable warrant available price per share expiration period											2021-10
Stock price		$ 0.45
Issuance of unregistered warrants to purchase shares of common stock		32,854,606				2,160,000						2,160,000
Exercise price of warrants		$ 0.50				$ 2.50						$ 2.50
Public offering, number of common stock and warrants issued		32,854,606
Ally Bridge [Member]
Liquidity And Managements Plans [Line Items]
Proceeds from issuance of common stock, net of issuance costs					$ 2,000,000
Proceeds from exercise of common stock warrants				$ 0
Exercisable warrant available price per share expiration period				2022-08
Stock price					$ 1.50
Exercise price of warrants				$ 1.50	$ 1.50
Proceeds from issuance of common stock				$ 2,200,000	$ 2,200,000
Issuance of warrants to purchase shares of common stock					1,434,639
Roth Capital Partners, LLC, WestPark Capital and Chardan Capital [Member]
Liquidity And Managements Plans [Line Items]
Placement agent agreement, effective date						Mar. 28, 2017
Proceeds from issuance of common stock, net of issuance costs						$ 8,600,000
Proceeds from exercise of common stock warrants						$ 0
Public offering, number of shares issued						4,320,000
Stock price						$ 2.15						$ 2.15
Issuance of unregistered warrants to purchase shares of common stock						2,160,000						2,160,000
Exercise price of warrants						$ 2.50						$ 2.50
Class of warrant or rights, expiration date						Oct. 01, 2022
Dawson James Securities, Inc and WestPark Capital [Member]
Liquidity And Managements Plans [Line Items]
Placement agent agreement, effective date			Dec. 05, 2017
Proceeds from issuance of common stock, net of issuance costs			$ 2,900,000
Public offering, number of shares issued			4,925,000
Stock price			$ 0.68
Issuance of unregistered warrants to purchase shares of common stock			246,250
Exercise price of warrants			$ 0.85
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 21, 2018
Minimum public float limit for offering										$ 75,000,000
Placement agent agreement, effective date								Apr. 25, 2016
Securities purchase agreement, effective date								Apr. 29, 2016
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								$ 3.90
Exercisable warrant available price per share expiration period								2021-05
Stock price								$ 3.00
Issuance of unregistered warrants to purchase shares of common stock								1,163,526
Exercise price of warrants								$ 3.90
Public offering, number of common stock and warrants issued								1,662,191
Over-Allotment Option [Member]
Liquidity And Managements Plans [Line Items]
Proceeds from exercise of common stock warrants							$ 564
Purchase of common stock by underwriters to cover overallotments, number of shares							627,131
Follow-on Public Offering [Member]
Liquidity And Managements Plans [Line Items]
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		$ 0.50
Exercisable warrant available price per share expiration period		2023-01
Stock price		$ 0.45
Exercise price of warrants		$ 0.50
Public offering, number of common stock and warrants issued		32,854,606
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		32,854,606
Maximum [Member] \| Shelf Registration Statement [Member]
Liquidity And Managements Plans [Line Items]
Aggregate offering price										$ 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		32,854,606

Sales of Equity Securities - Additional Information (Detail) - USD ($)										1 Months Ended	3 Months Ended
	Jan. 31, 2018	Jan. 30, 2018	Dec. 08, 2017	Aug. 11, 2017	Aug. 09, 2017	Mar. 31, 2017	Mar. 31, 2017	Oct. 19, 2016	May 04, 2016	May 31, 2015	Mar. 31, 2018	Mar. 31, 2017
Class Of Stock [Line Items]
Shelf registration statement expiration period										May 21, 2018
Public offering, number of common stock and warrants issued		32,854,606
Issuance of unregistered warrants to purchase shares of common stock		32,854,606				2,160,000	2,160,000					2,160,000
Stock price		$ 0.45
Exercise price of warrants		$ 0.50				$ 2.50	$ 2.50					$ 2.50
Class of warrant or rights, term		5 years
Issuance of warrants to purchase shares of common stock, grant date fair value		$ 9,700,000				$ 2,800,000
Net cash proceeds from sale of securities								$ 9,000,000
Proceeds from exercise of common stock warrants								$ 7,500,000			$ 0	$ 5,258,935
Exercisable warrant available price per share expiration period											2021-10
Ally Bridge [Member]
Class Of Stock [Line Items]
Stock price					$ 1.50
Exercise price of warrants				$ 1.50	$ 1.50
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
Exercisable warrant available price per share expiration period				2022-08
Private offering, number of common stock and warrants issued					1,466,667
Issuance of warrants to purchase shares of common stock					1,434,639
Proceeds from issuance of common stock				$ 2,200,000	$ 2,200,000
Common stock issuance costs					$ 200,000
Roth Capital Partners, LLC, WestPark Capital and Chardan Capital [Member]
Class Of Stock [Line Items]
Placement agent agreement, effective date							Mar. 28, 2017
Issuance of unregistered warrants to purchase shares of common stock						2,160,000	2,160,000					2,160,000
Stock price						$ 2.15	$ 2.15					$ 2.15
Exercise price of warrants						$ 2.50	$ 2.50					$ 2.50
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
Public offering, number of shares issued							4,320,000
Class of warrant or rights, expiration date							Oct. 01, 2022
Dawson James Securities, Inc and WestPark Capital [Member]
Class Of Stock [Line Items]
Placement agent agreement, effective date			Dec. 05, 2017
Issuance of unregistered warrants to purchase shares of common stock			246,250
Stock price			$ 0.68
Exercise price of warrants			$ 0.85
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
Public offering, number of shares issued			4,925,000
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		32,854,606
Shelf Registration Statement [Member]
Class Of Stock [Line Items]
Shelf registration statement expiration period										May 21, 2018
Minimum public float limit for offering										$ 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									1,662,191
Issuance of unregistered warrants to purchase shares of common stock									1,163,526
Stock price									$ 3.00
Exercise price of warrants									$ 3.90
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 [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Aggregate offering price										$ 50,000,000
Follow-on Public Offering [Member]
Class Of Stock [Line Items]
Public offering, number of common stock and warrants issued		32,854,606
Stock price		$ 0.45
Exercise price of warrants		$ 0.50
Class of warrant or rights, term		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		32,854,606
Follow-on Public Offering [Member] \| Maximum [Member]
Class Of Stock [Line Items]
Issuance of warrants to purchase shares of common stock		32,854,606

Fair Value Measurement - Additional Information (Detail) - USD ($)			3 Months Ended
	Jan. 30, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed asset purchases as equipment financings obligations			$ 79,000	$ 181,000
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value	$ 9,700,000	$ 2,800,000
Issuance of unregistered warrants to purchase shares of common stock	32,854,606	2,160,000		2,160,000
Estimated grant date fair value of warrants	$ 0.29
Exercise price of warrants	$ 0.50	$ 2.50		$ 2.50
Class of warrant or rights, term	5 years
Follow-on Public Offering [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value	$ 9,700,000
Exercise price of warrants	$ 0.50
Class of warrant or rights, term	5 years
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			$ 79,000

Fair Value Measurement - Assumptions Used for Determining Fair Values of Common Stock Warrants (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2018	Jan. 30, 2018
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price		$ 0.45
January 30, 2018 Offering [Member]
Warrant Fair Value Black Scholes Method [Line Items]
Beginning stock price	$ 0.339
Exercise price	$ 0.50
Expected dividend yield	0.00%
Discount rate-bond equivalent yield	2.48%
Expected life (in years)	5 years
Expected volatility	99.00%

Balance Sheet Details - Schedule of Fixed Assets and Accrued Liabilities (Detail) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Fixed Assets
Machinery and equipment	$ 2,763,108	$ 2,841,388
Furniture and office equipment	152,964	147,976
Computer equipment and software	1,430,669	1,637,034
Leasehold improvements	557,020	553,529
Financed equipment	2,373,475	2,294,762
Construction in process	28,563	2,975
Total fixed assets, gross	7,305,799	7,477,664
Less accumulated depreciation and amortization	(4,316,212)	(4,354,097)
Total fixed assets, net	2,989,587	3,123,567
Accrued Liabilities
Accrued interest	327,203	326,602
Accrued payroll	438,460	224,813
Accrued vacation	544,614	474,953
Accrued bonuses	675,254	375,000
Accrued sales commissions	65,717	104,509
Current portion of deferred rent	127,044	116,681
Accrued other	92,977	129,805
Total accrued liabilities	$ 2,271,269	$ 1,752,363

Balance Sheet Details - Additional Information (Detail)	3 Months Ended
Balance Sheet Details - Additional Information (Detail)	Mar. 31, 2018 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Disposal of fixed assets	$ 209,000
Accumulated depreciation	$ 209,000

April 2014 Credit Facility - Additional Information (Detail) - USD ($)				3 Months Ended	12 Months Ended
	Jan. 30, 2018	Mar. 31, 2017	Apr. 30, 2014	Mar. 31, 2018	Dec. 31, 2014	Dec. 31, 2017	Jun. 28, 2017	Jun. 30, 2016
Line of Credit Facility [Line Items]
Exercise price of unregistered warrants	$ 0.50	$ 2.50
Warrant term		5 years
Issuance of unregistered warrants to purchase shares of common stock, grant date fair value	$ 9,700,000	$ 2,800,000
Maximum [Member]
Line of Credit Facility [Line Items]
Warrant issued to lender	32,854,606
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			17,655
Exercise price of unregistered warrants			$ 14.16
Warrant term			10 years
Oxford Finance LLC [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Debt default limit amount			$ 250,000
Debt default final judgment amount			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
Line of Credit Facility fees amount payable			$ 50,000
Line of Credit Facility, interest rate during period			7.95%
Percentage of final interest payment due at maturity			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				$ 14,000		$ 33,000
Effective annual interest rate				13.87%		13.87%
Total remaining principal payments due during fiscal year ending December 31, 2018				$ 693,000
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)		3 Months Ended		12 Months Ended
Equipment Financings - Additional Information (Detail)	Jan. 26, 2018 USD ($) Payment	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Capital Leased Assets [Line Items]
Financed equipment		$ 2,373,475		$ 2,294,762
Accumulated depreciation related to financed equipment		826,000		$ 759,000
Fixed asset purchases	$ 240,000	53,980	$ 127,223
Fixed asset maintenance obligations	$ 10,000	5,000
Number of lease payments \| Payment	22
Lease payments per month	$ 11,081
Lease agreement commencement and repayment date	Jun. 30, 2018
Equipment purchases		$ 98,000
Equipment financings aggregate weighted average effective annual interest rate		12.38%		13.51%
Equipment financings maturity date on outstanding arrangements range, Start		2018-06
Equipment financings maturity date on outstanding arrangements range, End		2024-09
Interest expense to equipment financings		$ 82,674	82,526
Present value of minimum lease payment due within one year		476,000
Equipment Financings [Member]
Capital Leased Assets [Line Items]
Depreciation expense related to financed equipment		67,000	55,000
Interest expense to equipment financings		$ 43,000	$ 38,000
Minimum [Member] \| Equipment Financings [Member]
Capital Leased Assets [Line Items]
Financed equipment useful life		3 years
Maximum [Member] \| Equipment Financings [Member]
Capital Leased Assets [Line Items]
Financed equipment useful life		7 years

Equipment Financings - Schedule of Remaining Future Minimum Lease Payments for Financed Equipment Obligations (Detail)	Mar. 31, 2018 USD ($)
Capital Lease Obligations [Abstract]
2018	$ 394,959
2019	505,077
2020	419,817
2021	303,228
2022	260,462
Thereafter	262,950
Total payments	2,146,493
Less amount representing interest	(547,450)
Present value of payments	1,599,043
2018	66,456
2019	80,200
2020	64,163
2021	53,252
2022	56,005
Thereafter	40,641
Total payments	360,717
Present value of payments	$ 360,717

Stock-Based Compensation - Additional Information (Detail)				3 Months Ended		12 Months Ended
	Jul. 31, 2017 $ / shares shares	May 31, 2017 $ / shares shares	May 02, 2017 shares	Mar. 31, 2018 USD ($) Plan $ / shares shares	Mar. 31, 2017	Dec. 31, 2017 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of equity incentive plans \| Plan				2
Total Shares Outstanding				1,807,827		2,449,284
Number of shares remaining forfeited				641,457
Unrecognized share-based compensation expense, weighted-average recognition period				2 years 4 months 24 days
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Estimated forfeitures rate				0.00%	0.00%
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Estimated forfeitures rate				8.00%	8.00%
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value of options outstanding \| $				$ 0		$ 0
Intrinsic value of options exercisable \| $				0		0
Intrinsic value of options vested and unvested expected to vest \| $				0		$ 0
RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Intrinsic value shares, RSUs outstanding \| $				55,000
Intrinsic value amount, RSUs unvested and vested expected to vest \| $				$ 55,000
RSUs outstanding				185,920		360,920
Vested				10,920
Issuance of restricted stock units				0
Weighted-average estimated fair value of options granted \| $ / shares				$ 2.23		$ 1.87
Total RSUs forfeited				175,000
Stock Options and RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized share-based compensation expense, stock options \| $				$ 1,197,000
2013 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock options and RSUs authorized				333,333
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member}
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average exercise price per share \| $ / shares	$ 1.39	$ 1.50
Weighted-average estimated fair value of options granted \| $ / shares	$ 0.83	$ 0.99
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			550,000
Number of shares remaining forfeited				622,500
Number of shares vested				0
2013 Equity Incentive Plan [Member] \| Performance Stock Options [Member} \| Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted	75,000
Number of shares remaining forfeited						2,500
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		200,000
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		100,000
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		75,000
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		75,000
2013 Equity Incentive Plan [Member] \| Time-Based RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average estimated fair value of options granted \| $ / shares		$ 1.50
Vesting period				1 year
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		50,000
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		25,000
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			25,000
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			25,000
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			175,000
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		$ 1.50
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		25,000
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		25,000
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			25,000
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			25,000
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			175,000
2013 Equity Incentive Plan [Member] \| Performance RSU Granted on May 31, 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested			0
Total RSUs forfeited			175,000
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				3,522,955
Stock options and RSUs issued				2,033,009
Total Shares Outstanding				1,860,698
Common stock, shares authorized				1,489,946
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				333,333
Stock options and RSUs issued				158,049
Total Shares Outstanding				133,049
Common stock, shares authorized				175,284

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares Outstanding, Beginning Balance	2,449,284
Number of Shares, Cancelled/forfeited/expired	(641,457)
Number of Shares Outstanding, Ending Balance	1,807,827	2,449,284
Number of Shares, Vested and unvested expected to vest, Ending Balance	1,763,848
Weighted Average Exercise Price Per Share, Outstanding, Beginning Balance	$ 3.79
Weighted Average Exercise Price Per Share, Cancelled/forfeited/expired	1.60
Weighted Average Exercise Price Per Share, Outstanding, Ending Balance	4.57	$ 3.79
Weighted Average Exercise Price Per Share, Vested and unvested expected to vest, Ending Balance	$ 4.65
Weighted Average Remaining Contractual Term in Years, Outstanding	8 years 4 months 24 days	8 years 9 months 18 days
Weighted Average Remaining Contractual Term in Years, Vested and unvested expected to vest	8 years 3 months 18 days

Stock-Based Compensation - Summary of RSU Activity (Detail) - RSUs [Member]	3 Months Ended
	Mar. 31, 2018 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares Outstanding, Beginning Balance \| shares	360,920
Number of Shares, Granted \| shares	0
Number of share, Vested and issued \| shares	0
Number of share, Forfeited \| shares	(175,000)
Number of Shares Outstanding, Ending Balance \| shares	185,920
Number of Shares, Vested and unvested expected to vest, Ending Balance \| shares	185,920
Weighted Average Grant Date Fair Value, Outstanding, Beginning Balance \| $ / shares	$ 1.87
Weighted Average Grant Date Fair Value, Granted \| $ / shares	0
Weighted Average Grant Date Fair Value, Vested and issued \| $ / shares	0
Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	1.50
Weighted Average Grant Date Fair Value, Outstanding, Ending Balance \| $ / shares	2.23
Weighted Average Grant Date Fair Value, Vested and unvested expected to vest, Ending Balance \| $ / shares	$ 2.23

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
	Mar. 31, 2018	Mar. 31, 2017
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 183,166	$ 293,619
Stock Options [Member] \| Cost of revenues [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	17,579	31,770
Stock Options [Member] \| Research and Development Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	37,147	29,256
Stock Options [Member] \| General and Administrative Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	105,175	192,053
Stock Options [Member] \| Sales and Marketing Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	23,265	40,540
RSUs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	225,263	373,222
RSUs [Member] \| Cost of revenues [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	(17,250)	15,167
RSUs [Member] \| Research and Development Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	10,015	14,358
RSUs [Member] \| General and Administrative Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	40,059	29,933
RSUs [Member] \| Sales and Marketing Expenses [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation	$ 9,273	$ 20,145

Common Stock Warrants Outstanding - Summary of Equity-Classified Common Stock Warrant Activity (Detail) - Warrants [Member] - $ / shares		3 Months Ended	12 Months Ended
	Dec. 08, 2017	Mar. 31, 2018	Dec. 31, 2017
Class Of Warrant Or Right [Line Items]
Number of Shares, Outstanding, Beginning Balance		8,647,996
Number of Shares, Issued	246,250	32,854,606
Number of Shares, Outstanding, Ending Balance		41,502,602	8,647,996
Weighted Average Exercise Price Per Share, Outstanding, Beginning Balance		$ 2.63
Weighted Average Exercise Price Per Share, Issued		0.50
Weighted Average Exercise Price Per Share, Outstanding, Ending Balance		$ 0.94	$ 2.63
Average Remaining Contractual Term (in years)		4 years 7 months 6 days	4 years

Common Stock Warrants Outstanding - Equity-Classified Common Stock Warrants, Outstanding (Detail) - $ / shares	3 Months Ended
	Mar. 31, 2018	Jan. 30, 2018	Dec. 31, 2017	Mar. 31, 2017
Class Of Warrant Or Right [Line Items]
Exercise price of warrants		$ 0.50		$ 2.50
Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants		$ 0.50
Total Shares Outstanding	41,502,602		8,647,996
Weighted Average Exercise Price 0.50 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants	$ 0.50
Total Shares Outstanding	32,854,606
Weighted Average Contractual Life (in years)	4 years 9 months 18 days
Weighted Average Exercise Price 0.85 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants	$ 0.85
Total Shares Outstanding	246,250
Weighted Average Contractual Life (in years)	4 years 8 months 12 days
Weighted Average Exercise Price 1.10 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants	$ 1.10
Total Shares Outstanding	2,910,281
Weighted Average Contractual Life (in years)	3 years 7 months 6 days
Weighted Average Exercise Price 1.50 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants	$ 1.50
Total Shares Outstanding	1,434,639
Weighted Average Contractual Life (in years)	4 years 4 months 24 days
Weighted Average Exercise Price 2.50 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants	$ 2.50
Total Shares Outstanding	2,160,000
Weighted Average Contractual Life (in years)	4 years 6 months
Weighted Average Exercise Price 3.90 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants	$ 3.90
Total Shares Outstanding	1,163,526
Weighted Average Contractual Life (in years)	3 years 1 month 6 days
Weighted Average Exercise Price 4.68 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants	$ 4.68
Total Shares Outstanding	581,153
Weighted Average Contractual Life (in years)	1 year 10 months 24 days
Weighted Average Exercise Price 29.72 [Member] \| Warrants [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants	$ 29.72
Total Shares Outstanding	152,147
Weighted Average Contractual Life (in years)	1 year 6 months

Common Stock Warrants Outstanding - Additional Information (Detail) - USD ($)		3 Months Ended
	Dec. 08, 2017	Mar. 31, 2018	Jan. 30, 2018	Mar. 31, 2017
Class Of Warrant Or Right [Line Items]
Exercise price of warrants			$ 0.50	$ 2.50
Common stock warrants outstanding, intrinsic value		$ 0
Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants issued	246,250	32,854,606
Class of warrant or rights, first exercisable date		Jun. 05, 2018
Class of warrant or rights, expiration date		Dec. 05, 2022
Issuance of warrants to purchase shares of common stock			32,854,606
Exercise price of warrants			$ 0.50

Net Loss per Common Share - Schedule of Anti-Dilutive Securities Excluded from Computations of Diluted Weighted-Average Shares (Detail) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	43,496,878	10,109,419
Warrants Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	41,502,602	9,003,137
RSUs Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	185,920	174,249
Preferred Warrants Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	529	529
Common Options Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common share equivalents	1,807,827	931,504

Commitments and Contingencies - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Feb. 29, 2016	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Loss Contingencies [Line Items]
Unconditional purchase commitment aggregate amount	$ 1,062,500	$ 500,000
Unconditional purchase commitment payment terms		Quarterly
Unconditional purchase commitment period		May 31, 2020
Total expense for sales tax and maintenance obligations		$ 29,000	$ 18,000
Sales tax and maintenance obligations incurred but not paid		64,000		$ 46,000
Total payments for future sales tax and maintenance obligations		$ 360,717
Minimum [Member]
Loss Contingencies [Line Items]
Unconditional purchase commitment, quarterly payment amount	$ 62,500

Related Party Transactions - Additional Information (Detail)			3 Months Ended			12 Months Ended
	May 15, 2018 USD ($)	Feb. 01, 2017	Mar. 31, 2018 USD ($) ft²	Mar. 31, 2017 USD ($)	Mar. 31, 2015	Dec. 31, 2017 USD ($)
Related Party Transaction [Line Items]
Rental income				$ 38,412
San Diego California Facility [Member]
Related Party Transaction [Line Items]
Lease expiration date		Mar. 31, 2017
Rental income			$ 38,000			$ 51,000
Aegea Biotechnologies, Inc [Member]
Related Party Transaction [Line Items]
Reimbursement for shared patent costs						$ 15,000
Aegea Biotechnologies, Inc [Member] \| Subsequent Event [Member]
Related Party Transaction [Line Items]
Reimbursement for shared patent costs	$ 19,000
Nonexecutive [Member] \| San Diego California Facility [Member]
Related Party Transaction [Line Items]
Leased facility, expansion of original premises \| ft²			9,849
Lease agreement date of commencement			Mar. 30, 2015
Leased facility, rent expense per month			$ 12,804
Lease facility, refundable security deposit amount			12,804
Lease expiration date					Jul. 31, 2015
Lease agreement, amount of security deposit applied against additional rents owed			16,000
Lease agreement, amount of additional rents waived			$ 3,200

Subsequent Events - Additional Information (Detail) - USD ($)		3 Months Ended	12 Months Ended
	May 15, 2018	Mar. 31, 2018	Dec. 31, 2017
Subsequent Event [Line Items]
Insurance premiums financed through third-parties		$ 80,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Insurance premiums financed through third-parties	$ 387,000
Aegea Biotechnologies, Inc [Member]
Subsequent Event [Line Items]
Reimbursement for shared patent costs			$ 15,000
Aegea Biotechnologies, Inc [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Reimbursement for shared patent costs	$ 19,000