SCYNEXIS (SCYX) 10-Q 11 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	May 01, 2020
Cover [Abstract]
Entity Registrant Name	SCYNEXIS INC
Trading Symbol	SCYX
Entity Central Index Key	0001178253
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		98,587,061
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity File Number	001-36365
Entity Tax Identification Number	56-2181648
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	1 Evertrust Plaza
Entity Address, Address Line Two	13th Floor
Entity Address, City or Town	Jersey City
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07302-6548
City Area Code	201
Local Phone Number	884-5485
Document Quarterly Report	true
Document Transition Report	false
Title of Each Class	Common Stock, par value $0.001 per share
Name of Each Exchange on Which Registered	NASDAQ

Unaudited Condensed Consolidate

Unaudited Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 20,253	$ 41,920
Short-term investments	14,267	6,494
Prepaid expenses and other current assets	2,270	3,988
Total current assets	36,790	52,402
Other assets	812	812
Deferred offering costs	110	70
Restricted cash	273	273
Property and equipment, net	381	405
Operating lease right-of-use asset (See Note 7)	3,143	3,191
Total assets	41,509	57,153
Current liabilities:
Accounts payable	5,222	7,177
Accrued expenses	1,792	3,801
Operating lease liability, current portion (See Note 7)	40	36
Total current liabilities	7,054	11,014
Warrant liabilities	13,628	18,396
Convertible debt and derivative liability (See Note 6)	11,100	11,522
Operating lease liability (See Note 7)	3,272	3,326
Total liabilities	35,054	44,258
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value, authorized 5,000,000 shares as of March 31, 2020 and December 31, 2019; 0 shares issued and outstanding as of March 31, 2020 and December 31, 2019	0	0
Common stock, $0.001 par value, 250,000,000 shares authorized as of March 31, 2020 and December 31, 2019; 97,876,042 and 97,413,721 shares issued and outstanding as of March 31, 2020 and December 31, 2019, respectively	98	97
Additional paid-in capital	284,787	284,226
Accumulated deficit	(278,430)	(271,428)
Total stockholders’ equity	6,455	12,895
Total liabilities and stockholders’ equity	$ 41,509	$ 57,153

Unaudited Condensed Consolida_2

Unaudited Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	97,876,042	97,413,721
Common stock, shares outstanding (in shares)	97,876,042	97,413,721

Unaudited Condensed Consolida_3

Unaudited Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 0	$ 64
Operating expenses:
Research and development	9,866	9,684
Selling, general and administrative	2,613	2,241
Total operating expenses	12,479	11,925
Loss from operations	(12,479)	(11,861)
Other (income) expense:
Loss on extinguishment of debt	0	814
Amortization of debt issuance costs and discount	278	200
Interest income	(147)	(281)
Interest expense	210	367
Other income	(350)	0
Warrant liabilities fair value adjustment	(4,768)	6,522
Derivative liability fair value adjustment	(700)	3,425
Total other (income) expense	(5,477)	11,047
Net loss	$ (7,002)	$ (22,908)
Net loss per share - basic and diluted	$ (0.07)	$ (0.46)
Weighted average common shares outstanding – basic and diluted	97,445,775	49,317,575

Unaudited Condensed Consolida_4

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (7,002)	$ (22,908)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	28	29
Stock-based compensation expense	410	492
Accretion of investments discount	(31)	(82)
Amortization of debt issuance costs and discount	278	200
Warrant liabilities fair value adjustment	(4,768)	6,522
Derivative liability fair value adjustment	(700)	3,425
Noncash operating lease expense for right-of-use asset	48	48
Loss on extinguishment of debt	0	814
Changes in operating assets and liabilities:
Prepaid expenses, other assets, deferred costs, and other	1,734	6,390
Accounts payable, accrued expenses, and other	(4,054)	(1,367)
Deferred revenue	0	(64)
Net cash used in operating activities	(14,057)	(6,501)
Cash flows from investing activities:
Maturities of investments	6,477	24,638
Purchases of property and equipment	(4)	0
Purchases of investments	(14,235)	(18,041)
Net cash (used in) provided by investing activities	(7,762)	6,597
Cash flows from financing activities:
Proceeds from common stock issued	214	2,588
Payments of offering costs and underwriting discounts and commissions	(7)	(77)
Proceeds from common stock issuance under employee stock purchase plan	18	20
Repurchase of shares to satisfy tax withholdings	(73)	0
Proceeds from senior convertible notes	0	16,000
Payments of senior convertible notes issuance costs	0	(1,143)
Payment of loan payable expected to be refinanced	0	(15,973)
Net cash provided by financing activities	152	1,415
Net (decrease) increase in cash, cash equivalents, and restricted cash	(21,667)	1,511
Cash, cash equivalents, and restricted cash at beginning of period	42,193	11,767
Cash, cash equivalents, and restricted cash at end of period	20,526	13,278
Supplemental cash flow information:
Cash paid for interest	420	411
Cash received for interest	129	291
Noncash financing and investing activities:
Operating lease liabilities arising from obtaining right-of-use assets	0	3,365
Deferred offering and issuance costs included in accounts payable and accrued expenses	40	110
Deferred offering costs reclassified to additional-paid-in capital	$ 0	$ 2

Description of Business and Bas

Description of Business and Basis of Preparation	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of Business and Basis of Preparation	1. Organization SCYNEXIS, Inc. (“SCYNEXIS” or the “Company”) is a Delaware corporation formed on November 4, 1999. SCYNEXIS is a biotechnology company, headquartered in Jersey City, New Jersey, pioneering innovative medicines to help millions of patients worldwide in need of new options to overcome and prevent difficult-to-treat and drug resistant infections. The Company is developing its lead product candidate, ibrexafungerp, as a broad-spectrum, intravenous (IV)/oral agent in late stage development for multiple indications, ranging from the treatment of vaginal yeast infections in the community setting to life-threatening invasive fungal infections in hospitalized patients. The Company has incurred significant losses and negative cash flows from operations since its initial public offering in May 2014 and expects to continue to incur losses and negative cash flows for the foreseeable future. As a result, the Company had an accumulated deficit of $278.4 million at March 31, 2020 and limited capital resources to fund ongoing operations. These capital resources primarily comprised cash and cash equivalents of $20.3 million and short-term investments of $14.3 million at March 31, 2020. While the Company believes its capital resources are sufficient to fund the Company’s on-going operations for a period of a least 12 months subsequent to the issuance of the accompanying unaudited condensed consolidated financial statements, the Company's liquidity could be materially affected over this period by, among other things: (1) its ability to raise additional capital through equity offerings, debt financings, or other non-dilutive third-party funding; (2) costs associated with new or existing strategic alliances, or licensing and collaboration arrangements; (3) negative regulatory events or unanticipated costs related to its development of ibrexafungerp; or (4) any other unanticipated material negative events or costs. Should one or more of these negative events or costs materially affect its liquidity, the Company’s available capital resources may not be sufficient for it to continue to meet its obligations as they become due over the next 12 months. If the Company is unable to meet its obligations when they become due, the Company may have to delay expenditures, reduce the scope of its research and development programs, or make significant changes to its operating plan. The accompanying unaudited condensed consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. Intercompany balances and transactions are eliminated in consolidation. Shelf Registration Filing On August 31, 2018, the Company filed a shelf registration statement on Form S-3 (File No. 333-227167) with the Securities and Exchange Commission (“SEC”), which was declared effective on September 14, 2018 (the “Shelf Registration”). The Shelf Registration contained three prospectuses: • a base prospectus which covers the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $175.0 million of the Company’s common stock, preferred stock, debt securities and warrants, including common stock or preferred stock issuable upon conversion of debt securities, common stock issuable upon conversion of preferred stock, or common stock, preferred stock or debt securities issuable upon the exercise of warrants; • a prospectus covering the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $25.0 million of the Company's common stock that may be issued and sold under a Controlled Equity Offering Sales Agreement SM • a warrant prospectus covering the offering, issuance, and sale of the Company’s common stock issuable upon the exercise of warrants, consisting of (i) warrants to purchase 4,218,750 shares of the Company’s common stock at an exercise price of $3.00 per share originally issued by the Company on June 24, 2016, (ii) warrants to purchase 13,198,075 shares of the Company’s common stock at an exercise price of $1.85 per share originally issued by the Company on March 8, 2018, and (iii) warrants to purchase 7,988,175 shares of the Company’s common stock at an exercise price of $2.00 per share originally issued by the Company on March 8, 2018. The warrants to purchase 13,198,075 shares of the Company’s common stock expired on March 14, 2019. Upon full exercise for cash of the warrants outstanding on March 31, 2020, the holders of the warrants would pay the Company an aggregate of approximately $28.6 million. See Note 8 for further details December 2019 Public Offering On December 12, 2019, 38,888,889 The common stock that may be offered, issued and sold by the Company under the Sales Agreement is included in the $175.0 million of securities that may be offered, issued and sold by the Company under the base prospectus. Upon termination of the Sales Agreement with Cantor, any portion of the $25.0 million included in the Sales Agreement that is not sold pursuant to the Sales Agreement will be available for sale in other offerings pursuant to the base prospectus and a corresponding prospectus supplement. As of March 31, 2020, approximately $127.3 million of securities registered under the base prospectus are available to be offered, issued and sold by the Company. Unaudited Interim Condensed Consolidated Financial Information The accompanying unaudited condensed consolidated financial statements and notes have been prepared in accordance with accounting principles generally accepted in the United States (“US GAAP”), as contained in the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (the “Codification” or “ASC”) for interim financial information. In the opinion of management, the interim financial information includes all adjustments of a normal recurring nature necessary for a fair presentation of the results of operations, financial position, and cash flows. The results of operations for the three months ended March 31, 2020, are not necessarily indicative of the results for the full year or the results for any future periods. These unaudited condensed consolidated financial statements should be read in conjunction with the financial statements and notes set forth in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 11, 2020. Use of Estimates The preparation of unaudited condensed consolidated financial statements in conformity with US GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates. Significant estimates include: determination of the fair value of stock-based compensation grants

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. The accompanying unaudited condensed consolidated financial statements and notes follow the same significant accounting policies as those described in the notes to the audited consolidated financial statements of the Company for the year ended December 31, 2019, except as described below. Basic and Diluted Net Loss per Share of Common Stock The Company calculates net loss per common share in accordance with ASC Earnings Per Share The following potentially dilutive shares of common stock have not been included in the computation of diluted net loss per share for the three months ended March 31, 2020 and 2019, as the result would be anti-dilutive: Three Months Ended March 31, 2020 2019 Warrants to purchase Series C-1 Preferred — 14,033 Warrants to purchase common stock associated with Solar loan agreement 122,435 122,435 Warrants to purchase common stock associated with June 2016 public offering 4,218,750 4,218,750 Warrants to purchase common stock associated with March 2018 public offering – Series 2 7,988,175 7,988,175 Outstanding stock options 7,684,762 5,310,498 Outstanding restricted stock units 862,514 107,841 Common stock associated with 6% convertible senior notes 11,382,000 13,008,000 Warrants to purchase common stock associated with December 2019 Public Offering 44,722,222 — Total 76,980,858 30,769,732 Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Recently Adopted Accounting Pronouncements In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement

Short-term Investments

Short-term Investments	3 Months Ended
	Mar. 31, 2020
Investments Debt And Equity Securities [Abstract]
Short-term Investments	3. Short-term Investments The following table summarizes the held-to-maturity securities held at March 31, 2020 and December 31, 2019 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of March 31, 2020 U.S. government securities $ 6,000 $ 18 $ (15 ) $ 6,003 Commercial paper 8,267 — — 8,267 Total short-term investments $ 14,267 $ 18 $ (15 ) $ 14,270 Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2019 U.S. government securities $ 1,996 $ 15 $ (14 ) $ 1,997 Commercial paper 998 — — 998 Overnight repurchase agreement 3,500 — — 3,500 Total short-term investments $ 6,494 $ 15 $ (14 ) $ 6,495 All held-to-maturity short-term investments at March 31, 2020 and December 31, 2019 will mature in less than one year. The gross unrealized gains and losses for the Company’s commercial paper and overnight repurchase agreement are not significant. The Company carries short-term investments at amortized cost. The fair value of the short-term investments is determined based on “Level 1” inputs, which consist of quoted prices in active markets for identical assets.

Prepaid Expenses and Other Curr

Prepaid Expenses and Other Current Assets	3 Months Ended
	Mar. 31, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	4. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): March 31, 2020 December 31, 2019 Prepaid research and development services $ 1,176 $ 3,043 Prepaid insurance 92 252 Other prepaid expenses 88 19 Other current assets 914 674 Total prepaid expenses and other current assets $ 2,270 $ 3,988

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consisted of the following (in thousands): March 31, 2020 December 31, 2019 Accrued research and development expenses $ 828 $ 1,296 Accrued employee bonus compensation 365 1,798 Other accrued expenses 599 707 Total accrued expenses $ 1,792 $ 3,801

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Borrowings	6. Borrowings On September 30, 2016, the Company entered into a loan agreement with Solar Capital Ltd. (“Solar”), in its capacity as administrative and collateral agent and as lender. Pursuant to the loan agreement, Solar was providing the Company with a 48-month secured term loan in the amount of $15.0 million. The term loan bore interest at a floating rate equal to the LIBOR rate in effect plus 8.49%. The Solar term loan was paid in full in March 2019. On March 7, 2019, the Company entered into a Senior Convertible Note Purchase Agreement (the “March 2019 Note Purchase Agreement”) with Puissance Life Science Opportunities Fund VI (“Puissance”). Pursuant to the March 2019 Note Purchase Agreement, on March 7, 2019, the Company issued and sold to Puissance $16.0 million aggregate principal amount of its 6.0% Senior Convertible Notes due 2025 (the “Notes”), resulting in $14.7 million in net proceeds after deducting $1.3 million for an advisory fee and other issuance costs. The Company used the net proceeds to pay the remaining outstanding Solar term loan in full and recorded a loss on debt extinguishment of $0.8 million As of March 31, 2020, the Company’s $11.1 million in convertible debt and derivative liability consists of the convertible debt balance of $8.6 million presented net of the unamortized debt issuance costs allocated to the convertible debt of $0.5 million and the bifurcated embedded conversion option derivative liability of $2.5 million. In connection with the Company’s issuance of its Notes, the Company bifurcated the embedded conversion option, inclusive of the interest make-whole provision and make-whole fundamental change provision, and recorded the embedded conversion option as a long-term derivative liability in the Company’s balance sheet in accordance with ASC 815, Derivatives and Hedging In April 2019, Puissance converted $2.0 million of the Notes for 1,626,000 shares of common stock. Upon conversion of the $2.0 million of the Notes, the Company recognized a $0.2 million extinguishment loss which represents the difference between the total net carrying amount of the convertible debt and derivative liabilities of $2.8 million and the fair value of the consideration issued of $3.0 million. The Company estimated the fair value of the convertible debt and derivative liability using a binomial lattice valuation model and Level 3 inputs. At March 31, 2020, the fair value of the senior convertible notes is $10.2 million. The Notes were issued and sold for cash at a purchase price equal to 100% of their principal amount, in reliance on the exemption from registration The holder of the Notes may convert their Notes at their option at any time prior to the close of business on the business day immediately preceding March 15, 2025 into shares of the Company’s common stock. The initial conversion rate is 739.0983 shares of common stock per $1,000 principal amount of Notes, which is equivalent to an initial conversion price of approximately $1.35, and is subject to adjustment in certain events described in the March 2019 Note Purchase Agreement. The Holder upon conversion may also be entitled to receive, under certain circumstances, an interest make-whole payment payable in shares of common stock. In addition, following certain corporate events that occur prior to the maturity date, the Company will, in certain circumstances, increase the conversion rate if the holder elects to convert its Notes in connection with such a corporate event. Subject to adjustment in the conversion rate, the number of shares that the Company may deliver in connection with a conversion of the Notes, including those delivered in connection with an interest make-whole payment, will not exceed a cap of 813 shares of common stock per $1,000 principal amount of the Notes. On or after March 15, 2022, the Company has the right, at its election, to redeem all or any portion of the Notes not previously converted if the last reported sale price per share of common stock exceeds 130% of the conversion price on each of at least 20 trading days (whether or not consecutive) during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice. The redemption price will be 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. If a “fundamental change” (as defined in the March 2019 Note Purchase Agreement) occurs, then, subject to certain exceptions, the Company must offer to repurchase the Notes for cash at a repurchase price of 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the repurchase date.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Leases On March 1, 2018, the Company entered into a long-term lease agreement for approximately 19,275 square feet of office space in Jersey City, New Jersey, that the Company identified as an operating lease under ASC 840 (the “Lease”). The lease term is eleven years from August 1, 2018, the commencement date, with total lease payments of $7.3 million over the lease term. The Company has the option to renew for two consecutive five-year periods from the end of the first term and the Company is not reasonably certain that the option to renew the Lease will be exercised. Under the Lease, the Company furnished a security deposit in the form of a standby letter of credit in the amount of $0.3 million, which was reduced by fifty-five thousand dollars on the first anniversary of the commencement date. The security deposit will continue to be reduced by fifty-five thousand dollars every two years on the commencement date anniversary for eight years. The security deposit is classified as restricted cash in the accompanying unaudited condensed consolidated balance sheets . The consideration in the Lease allocated to the single lease component includes the fixed payments for the right to use the office space as well as common area maintenance. The Lease also contains costs associated with certain expense escalation, property taxes, insurance, parking, and utilities which are all considered variable payments and are excluded from the operating lease liability. The incremental borrowing rate utilized approximated the prevailing market interest rate the Company would incur to borrow a similar amount equal to the total Lease payments on a collateralized basis over the term of the Lease. The following table summarizes certain quantitative information associated with the amounts recognized in the unaudited condensed consolidated financial statements for the Lease (dollars in thousands): Three Months Ended March 31, 2020 Operating lease cost $ 166 Variable lease cost 21 Total operating lease expense $ 187 Cash paid for amounts included in the measurement of operating lease liability $ 167 Remaining Lease term (years) 9.34 Discount rate 15 % Future minimum lease payments for the Lease as of March 31, 2020 are as follows (in thousands): March 31, 2020 2020 $ 340 2021 517 2022 527 2023 715 2024 730 Thereafter 3,533 Total $ 6,362 The presentation of the operating lease liability and right-of-use asset as of March 31, 2020 are as follows (in thousands): March 31, 2020 Present value of future minimum lease payments $ 3,312 Operating lease liability, current portion $ 40 Operating lease liability, long-term portion 3,272 Total operating lease liability $ 3,312 Difference between future minimum lease payments and discounted cash flows $ 3,050 Operating lease right-of-use asset $ 3,143 License Arrangement with Potential Future Expenditures As of March 31, 2020, the Company had a license arrangement with Merck Sharp & Dohme Corp., or Merck, that involves potential future expenditures. Under the license arrangement, the Company exclusively licensed from Merck its rights to ibrexafungerp in the field of human health. Ibrexafungerp is the Company’s lead product candidate. Pursuant to the terms of the license agreement, Merck is eligible to receive milestone payments from the Company that could total $19.0 million upon occurrence of specific events, including initiation of a Phase 3 clinical study, new drug application, and marketing approvals in each of the U.S., major European markets and Japan. In addition, Merck is eligible to receive tiered royalties from the Company based on a percentage of worldwide net sales of ibrexafungerp. The aggregate royalty percentages are mid- to high-single digits. In December 2014, the Company and Merck entered into an amendment to the license agreement that deferred the remittance of a milestone payment due to Merck, such that no amount would be due upon initiation of the first Phase 2 clinical trial of a product containing the ibrexafungerp compound (the “Deferred Milestone”). The amendment also increased, in an amount equal to the Deferred Milestone, the milestone payment that would be due upon initiation of the first Phase 3 clinical trial of a product containing the ibrexafungerp compound. In December 2016 and January 2018, the Company entered into second and third amendments, respectively, to the license agreement with Merck which clarified what would constitute the initiation of a Phase 3 clinical trial for the purpose of milestone payment. Except as described above, all other terms and provisions of the license agreement remain in full force and effect. In January 2019, a milestone payment became due to Merck as a result of the initiation of the VANISH Phase 3 VVC program and was paid in March 2019. The milestone payment was recognized in the unaudited condensed consolidated statement of operations in research and development expense for the three months ended March 31, 2019 and is included in cash used in operating activities on the statement of cash flows. Clinical Development Arrangements The Company has entered into, and expects to continue to enter into, contracts in the normal course of business with various third parties who support its clinical trials, preclinical research studies, and other services related to its development activities. The scope of the services under these agreements can generally be modified at any time, and the agreement can be terminated by either party after a period of notice and receipt of written notice.

Stockholder's Equity

Stockholder's Equity	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Stockholder's Equity	8. Stockholders’ Equity Authorized, Issued, and Outstanding Common Stock The Company’s authorized common stock has a par value of $0.001 per share and consists of 250,000,000 shares as of March 31, 2020, and December 31, 2019; 97,876,042 and 97,413,721 shares were issued and outstanding at March 31, 2020, and December 31, 2019, respectively. The following table summarizes common stock share activity for the three months ended March 31, 2020 and 2019 (dollars in thousands): Three Months Ended March 31, 2020 Shares of Common Stock Common Stock Additional Paid-in Capital Accumulated Deficit Total Stockholders’ Equity Balance, December 31, 2019 97,413,721 $ 97 $ 284,226 $ (271,428 ) $ 12,895 Net loss — — — (7,002 ) (7,002 ) Stock-based compensation expense — — 410 — 410 Common stock issued through employee stock purchase plan 22,143 — 18 — 18 Common stock issued, net of expenses 285,276 1 206 — 207 Common stock issued for vested restricted stock units 154,902 — (73 ) — (73 ) Balance, March 31, 2020 97,876,042 $ 98 $ 284,787 $ (278,430 ) $ 6,455 Three Months Ended March 31, 2019 Shares of Common Stock Common Stock Additional Paid-in Capital Accumulated Deficit Total Stockholders’ Equity Balance, December 31, 2018 47,971,989 $ 48 $ 248,895 $ (217,718 ) $ 31,225 Net loss — — — (22,908 ) (22,908 ) Stock-based compensation expense — — 492 — 492 Common stock issued through employee stock purchase plan 19,259 — 20 — 20 Common stock issued, net of expenses 2,226,569 2 2,507 — 2,509 Common stock issued for vested restricted stock units 14,612 — (8 ) — (8 ) Balance, March 31, 2019 50,232,429 $ 50 $ 251,906 $ (240,626 ) $ 11,330 Shares Reserved for Future Issuance The Company had reserved shares of common stock for future issuance as follows: March 31, 2020 December 31, 2019 Outstanding stock options 7,684,762 5,261,860 Outstanding restricted stock units 862,514 966,394 Warrants to purchase common stock associated with June 2016 Public Offering 4,218,750 4,218,750 Warrants to purchase common stock associated with March 2018 Public Offering – Series 2 7,988,175 7,988,175 Warrants to purchase common stock associated with December 2019 Public Offering 44,722,222 44,722,222 Option to purchase common stock associated with December 2019 Public Offering — 5,833,333 Warrants to purchase common stock associated with Solar loan agreement 122,435 122,435 For possible future issuance for the conversion of the 6% senior convertible notes 11,382,000 11,382,000 For possible future issuance under 2014 Equity Incentive Plan (Note 9) 1,900,861 554,774 For possible future issuance under Employee Stock Purchase Plan 81,499 74,231 For possible future issuance under 2015 Inducement Award Plan (Note 9) 315,500 315,500 Total common shares reserved for future issuance 79,278,718 81,439,674 Convertible Debt and Derivative Liability In connection with the Company’s issuance of its Notes, the Company bifurcated the embedded conversion option, inclusive of the interest make-whole provision and make-whole fundamental change provision, and recorded the embedded conversion option as a long-term derivative liability in the Company’s balance sheet in accordance with ASC 815, Derivatives and Hedging The derivative liability will be remeasured at each reporting period using the binomial lattice model with changes in fair value recorded in the statements of operations in other (income) expense. For the three months ended March 31, 2020 and 2019, the Company recorded a gain of $0.7 million and a loss of $3.4 million due to the change in fair value of the derivative liability. Warrants Associated with June 2016, March 2018, and December 2019 Public Offerings The outstanding warrants associated with the June 2016, March 2018, and December 2019 public offerings contain a provision where the warrant holder has the option to receive cash, equal to the Black-Scholes fair value of the remaining unexercised portion of the warrant, as cash settlement in the event that there is a fundamental transaction (contractually defined to include various merger, acquisition or stock transfer activities). Due to this provision, ASC 480, Distinguishing Liabilities from Equity, Warrant Associated with Solar Loan Agreement On the closing date of t he Company’s previous loan agreement with Solar, p

Stock-based Compensation

Stock-based Compensation	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based Compensation	9. Stock-based Compensation Pursuant to the terms of the Company’s 2014 Equity Incentive Plan (“2014 Plan”), on January 1, 2020 and 2019, the Company automatically added 3,896,548 and 1,918,879 shares to the total number shares of common stock available for future issuance under the 2014 Plan, respectively. As of March 31, 2020, there were 1,900,861 shares of common stock available for future issuance under the 2014 Plan. As of March 31, 2020, there were 315,500 shares of common stock available for future issuance under the Company’s 2015 Inducement Award Plan (“2015 Plan”). During the three months ended March 31, 2020 and 2019, there were no granted options of the Company’s common stock under the 2015 Plan. The activity for the Company’s 2009 Stock Option Plan, 2014 Plan, and 2015 Plan, for the three months ended March 31, 2020, is summarized as follows: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in years) Aggregate Intrinsic Value ($000) Outstanding — December 31, 2019 5,261,860 $ 3.06 7.62 $ 60 Granted 2,563,400 $ 0.86 Exercised — — Forfeited/Cancelled (140,498 ) $ 1.80 Outstanding — March 31, 2020 7,684,762 $ 2.35 8.11 $ 28 Exercisable — March 31, 2020 3,326,023 $ 3.89 6.63 $ 23 Vested or expected to vest — March 31, 2020 7,684,762 $ 2.35 8.11 $ 28 Restricted stock unit (“RSU”) activity under the 2014 Plan and 2015 Plan for the three months ended March 31, 2020, is summarized as follows: Number of Shares Weighted Average Grant Date Fair Value Per Share Non-vested at December 31, 2019 966,394 $ 1.42 Granted 256,950 $ 0.86 Vested (231,439 ) $ 1.46 Forfeited/Cancelled (129,391 ) $ 1.26 Non-vested at March 31, 2020 862,514 $ 1.26 The fair value of RSUs is based on the market price of the Company’s common stock on the date of grant. RSUs generally vest 25% annually over a four-year period from the date of grant. Upon vesting, the RSUs are net share settled to cover the required withholding tax with the remaining shares issued to the holder. The Company recognizes compensation expense for such awards ratably over the corresponding vesting period. Compensation Cost The compensation cost that has been charged against income for stock awards under the 2014 Plan and the 2015 Plan was $0.4 million and $0.5 million for the three months ended March 31, 2020 and 2019, respectively. The total income tax benefit recognized in the statements of operations for share-based compensation arrangements was zero for both the three months ended March 31, 2020 and 2019. Cash received from options exercised was zero for both the three months ended March 31, 2020 and 2019. Stock-based compensation expense related to stock options is included in the following line items in the accompanying unaudited condensed consolidated statements of operations (in thousands): Three Months Ended March 31, 2020 2019 Research and development $ 136 $ 158 Selling, general and administrative 274 334 Total $ 410 $ 492

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	10. Fair Value Measurements The carrying amounts of certain financial instruments, including cash and cash equivalents, restricted cash, accounts receivable, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate their respective fair values due to the short-term nature of such instruments. Assets and Liabilities Measured at Fair Value on a Recurring Basis The Company evaluates its financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level in which to classify them for each reporting period. This determination requires significant judgments to be made. The following table summarizes the conclusions reached as of March 31, 2020 and December 31, 2019 for financial instruments measured at fair value on a recurring basis (in thousands): Fair Value Hierarchy Classification Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2020 Cash $ 195 $ 195 — — Restricted cash 273 273 — — Money market funds 20,058 20,058 — — Total assets $ 20,526 $ 20,526 — — Warrant liabilities $ 13,628 — — $ 13,628 Derivative liability 2,492 — — 2,492 Total liabilities $ 16,120 — — $ 16,120 December 31, 2019 Cash $ 23 $ 23 — — Restricted cash 273 273 — — Money market funds 41,897 41,897 — — Total assets $ 42,193 $ 42,193 — — Warrant liabilities $ 18,396 — — $ 18,396 Derivative liability 3,192 — — 3,192 Total liabilities $ 21,588 — — $ 21,588 The Company measures cash equivalents at fair value on a recurring basis. The fair value of cash equivalents is determined based on “Level 1” inputs, which consist of quoted prices in active markets for identical assets. Level 3 financial liabilities consist of the warrant liabilities for which there is no current market such that the determination of fair value requires significant judgment or estimation. Changes in fair value measurements categorized within Level 3 of the fair value hierarchy are analyzed each period based on changes in estimates or assumptions and recorded as appropriate. The Company uses the Black-Scholes option valuation model to value the Level 3 warrant liabilities at inception and on subsequent valuation dates. This model incorporates transaction details such as the Company’s stock price, contractual terms, maturity, risk free rates, as well as volatility. The unobservable input for all of the Level 3 warrant liabilities includes volatility. The historical volatility of the Company, using its closing common stock prices, is utilized to reflect future volatility over the expected term of the warrants. At March 31, 2020, the range and weighted average of the Level 3 volatilities utilized in the Black-Scholes model to fair value the warrant liabilities were 73.7% to 78.4% and 75.0%, respectively. Additionally, the expected term associated with the December 2019 Public Offering warrants is an unobservable unit given that the expiration of the warrants is the earlier of (i) such date that is six months after the Company publicly announces the approval from the U.S. Food and Drug Administration for ibrexafungerp for the treatment of vulvovaginal candidiasis and (ii) June 12, 2023. The Company uses the binomial lattice valuation model to value the Level 3 derivative liability at inception and on subsequent valuation dates. This model incorporates transaction details such as the Company’s stock price, contractual terms, dividend yield, risk-free rate, historical volatility, credit rating, market credit spread, and estimated effective yield. The unobservable inputs associated with the Level 3 derivative liability are adjusted equity volatility, market credit spread, and estimated yield. As of March 31, 2020, these inputs were 56.8%, 2,063 basis points, and 21.0%, respectively. The senior convertible notes are initially fair valued using the binomial lattice model and with the straight debt fair value calculated using the discounted cash flow method. The discounts for lack of marketability, 12.07% as of March 31, 2020, is then applied to the value of the senior convertible notes. The residual difference represents the fair value of the embedded derivative liability and the fair value of the embedded derivative liability is reassessed using the binomial lattice valuation model on a quarterly basis A reconciliation of the beginning and ending balances for liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) is as follows (in thousands): Warrant Liabilities Balance – December 31, 2019 $ 18,396 Gain adjustment to fair value (4,768 ) Balance – March 31, 2020 $ 13,628 Derivative Liability Balance – December 31, 2019 $ 3,192 Gain adjustment to fair value (700 ) Balance – March 31, 2020 $ 2,492

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	1 1 . Subsequent Events In April 2020, the Company entered into a Senior Convertible Note Purchase Agreement (“April 2020 Note Purchase Agreement”) with Puissance. Pursuant to the April 2020 Note Purchase Agreement, on April 9, 2020, the Company issued and sold to Puissance $10.0 million aggregate principal amount of its 6.0% Senior Convertible Notes due 2026. In April 2020, the Company entered into a Common Stock Purchase Agreement (“Common Stock Purchase Agreement”) with Aspire Capital Fund, LLC, an Illinois limited liability company (“Aspire Capital”), pursuant to which the Company has the right to sell to Aspire Capital from time to time in its sole discretion up to $20.0 million in shares of the Company’s common stock over the next 30 months, subject to certain limitations and conditions set forth in the Common Stock Purchase Agreement. In April 2020, the Company received a cash receipt of $3.1 million from a third party for the sale of a portion of the Company’s unused New Jersey Net Operating Losses (NOLs) and research and development credits. The income tax benefit for the sale of the NOLs and research and development credits for $3.1 million was recognized in April 2020. In April 2020, the Company received a letter from the Listing Qualifications Department staff of the Nasdaq Stock Market (“Nasdaq”) notifying the Company that, for the last 30 consecutive business days, the closing bid price for the Company’s common stock was below the $1.00 per share minimum required for continued listing on the Nasdaq Global Market as set forth in Nasdaq Listing Rule 5450(a)(1). In accordance with Nasdaq Listing Rule 5810(c)(3)(A) and the Nasdaq temporary relief in response to the COVID-19 pandemic effective on April 16, 2020, the Company has 180 calendar days from July 1, 2020, or until December 28, 2020, to regain compliance with the minimum bid price rule.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basic and Diluted Net Loss per Share of Common Stock	Basic and Diluted Net Loss per Share of Common Stock The Company calculates net loss per common share in accordance with ASC Earnings Per Share The following potentially dilutive shares of common stock have not been included in the computation of diluted net loss per share for the three months ended March 31, 2020 and 2019, as the result would be anti-dilutive: Three Months Ended March 31, 2020 2019 Warrants to purchase Series C-1 Preferred — 14,033 Warrants to purchase common stock associated with Solar loan agreement 122,435 122,435 Warrants to purchase common stock associated with June 2016 public offering 4,218,750 4,218,750 Warrants to purchase common stock associated with March 2018 public offering – Series 2 7,988,175 7,988,175 Outstanding stock options 7,684,762 5,310,498 Outstanding restricted stock units 862,514 107,841 Common stock associated with 6% convertible senior notes 11,382,000 13,008,000 Warrants to purchase common stock associated with December 2019 Public Offering 44,722,222 — Total 76,980,858 30,769,732
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842) Recently Adopted Accounting Pronouncements In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Summary of Antidilutive Securities Excluded from Computation of Weighted Average Common Stock Outstanding	The following potentially dilutive shares of common stock have not been included in the computation of diluted net loss per share for the three months ended March 31, 2020 and 2019, as the result would be anti-dilutive: Three Months Ended March 31, 2020 2019 Warrants to purchase Series C-1 Preferred — 14,033 Warrants to purchase common stock associated with Solar loan agreement 122,435 122,435 Warrants to purchase common stock associated with June 2016 public offering 4,218,750 4,218,750 Warrants to purchase common stock associated with March 2018 public offering – Series 2 7,988,175 7,988,175 Outstanding stock options 7,684,762 5,310,498 Outstanding restricted stock units 862,514 107,841 Common stock associated with 6% convertible senior notes 11,382,000 13,008,000 Warrants to purchase common stock associated with December 2019 Public Offering 44,722,222 — Total 76,980,858 30,769,732

Short-term Investments (Tables)

Short-term Investments (Tables)	3 Months Ended
	Mar. 31, 2020
Investments Debt And Equity Securities [Abstract]
Held-to-maturity Securities	The following table summarizes the held-to-maturity securities held at March 31, 2020 and December 31, 2019 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of March 31, 2020 U.S. government securities $ 6,000 $ 18 $ (15 ) $ 6,003 Commercial paper 8,267 — — 8,267 Total short-term investments $ 14,267 $ 18 $ (15 ) $ 14,270 Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2019 U.S. government securities $ 1,996 $ 15 $ (14 ) $ 1,997 Commercial paper 998 — — 998 Overnight repurchase agreement 3,500 — — 3,500 Total short-term investments $ 6,494 $ 15 $ (14 ) $ 6,495

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands): March 31, 2020 December 31, 2019 Prepaid research and development services $ 1,176 $ 3,043 Prepaid insurance 92 252 Other prepaid expenses 88 19 Other current assets 914 674 Total prepaid expenses and other current assets $ 2,270 $ 3,988

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): March 31, 2020 December 31, 2019 Accrued research and development expenses $ 828 $ 1,296 Accrued employee bonus compensation 365 1,798 Other accrued expenses 599 707 Total accrued expenses $ 1,792 $ 3,801

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Summary of Quantitative Information Associated with Amounts Recognized in Unaudited Condensed Consolidated Financial Statements for Lease	The following table summarizes certain quantitative information associated with the amounts recognized in the unaudited condensed consolidated financial statements for the Lease (dollars in thousands): Three Months Ended March 31, 2020 Operating lease cost $ 166 Variable lease cost 21 Total operating lease expense $ 187 Cash paid for amounts included in the measurement of operating lease liability $ 167 Remaining Lease term (years) 9.34 Discount rate 15 %
Future Minimum Lease Payments	Future minimum lease payments for the Lease as of March 31, 2020 are as follows (in thousands): March 31, 2020 2020 $ 340 2021 517 2022 527 2023 715 2024 730 Thereafter 3,533 Total $ 6,362
Presentation of Operating Lease Liability and Right-of-Use Asset	The presentation of the operating lease liability and right-of-use asset as of March 31, 2020 are as follows (in thousands): March 31, 2020 Present value of future minimum lease payments $ 3,312 Operating lease liability, current portion $ 40 Operating lease liability, long-term portion 3,272 Total operating lease liability $ 3,312 Difference between future minimum lease payments and discounted cash flows $ 3,050 Operating lease right-of-use asset $ 3,143

Stockholder's Equity (Tables)

Stockholder's Equity (Tables)	3 Months Ended
	Mar. 31, 2020
Equity [Abstract]
Summary of Common Stock Shares Activity	The following table summarizes common stock share activity for the three months ended March 31, 2020 and 2019 (dollars in thousands): Three Months Ended March 31, 2020 Shares of Common Stock Common Stock Additional Paid-in Capital Accumulated Deficit Total Stockholders’ Equity Balance, December 31, 2019 97,413,721 $ 97 $ 284,226 $ (271,428 ) $ 12,895 Net loss — — — (7,002 ) (7,002 ) Stock-based compensation expense — — 410 — 410 Common stock issued through employee stock purchase plan 22,143 — 18 — 18 Common stock issued, net of expenses 285,276 1 206 — 207 Common stock issued for vested restricted stock units 154,902 — (73 ) — (73 ) Balance, March 31, 2020 97,876,042 $ 98 $ 284,787 $ (278,430 ) $ 6,455 Three Months Ended March 31, 2019 Shares of Common Stock Common Stock Additional Paid-in Capital Accumulated Deficit Total Stockholders’ Equity Balance, December 31, 2018 47,971,989 $ 48 $ 248,895 $ (217,718 ) $ 31,225 Net loss — — — (22,908 ) (22,908 ) Stock-based compensation expense — — 492 — 492 Common stock issued through employee stock purchase plan 19,259 — 20 — 20 Common stock issued, net of expenses 2,226,569 2 2,507 — 2,509 Common stock issued for vested restricted stock units 14,612 — (8 ) — (8 ) Balance, March 31, 2019 50,232,429 $ 50 $ 251,906 $ (240,626 ) $ 11,330
Common Stock Reserved For Future Issuances	The Company had reserved shares of common stock for future issuance as follows: March 31, 2020 December 31, 2019 Outstanding stock options 7,684,762 5,261,860 Outstanding restricted stock units 862,514 966,394 Warrants to purchase common stock associated with June 2016 Public Offering 4,218,750 4,218,750 Warrants to purchase common stock associated with March 2018 Public Offering – Series 2 7,988,175 7,988,175 Warrants to purchase common stock associated with December 2019 Public Offering 44,722,222 44,722,222 Option to purchase common stock associated with December 2019 Public Offering — 5,833,333 Warrants to purchase common stock associated with Solar loan agreement 122,435 122,435 For possible future issuance for the conversion of the 6% senior convertible notes 11,382,000 11,382,000 For possible future issuance under 2014 Equity Incentive Plan (Note 9) 1,900,861 554,774 For possible future issuance under Employee Stock Purchase Plan 81,499 74,231 For possible future issuance under 2015 Inducement Award Plan (Note 9) 315,500 315,500 Total common shares reserved for future issuance 79,278,718 81,439,674

Stock-based Compensation (Table

Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Share-based Compensation, Stock Options, Activity	The activity for the Company’s 2009 Stock Option Plan, 2014 Plan, and 2015 Plan, for the three months ended March 31, 2020, is summarized as follows: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in years) Aggregate Intrinsic Value ($000) Outstanding — December 31, 2019 5,261,860 $ 3.06 7.62 $ 60 Granted 2,563,400 $ 0.86 Exercised — — Forfeited/Cancelled (140,498 ) $ 1.80 Outstanding — March 31, 2020 7,684,762 $ 2.35 8.11 $ 28 Exercisable — March 31, 2020 3,326,023 $ 3.89 6.63 $ 23 Vested or expected to vest — March 31, 2020 7,684,762 $ 2.35 8.11 $ 28
Schedule of Restricted Stock Units ("RSU") Activity	Restricted stock unit (“RSU”) activity under the 2014 Plan and 2015 Plan for the three months ended March 31, 2020, is summarized as follows: Number of Shares Weighted Average Grant Date Fair Value Per Share Non-vested at December 31, 2019 966,394 $ 1.42 Granted 256,950 $ 0.86 Vested (231,439 ) $ 1.46 Forfeited/Cancelled (129,391 ) $ 1.26 Non-vested at March 31, 2020 862,514 $ 1.26
Stock-Based Compensation Expense Related to Stock Options	Stock-based compensation expense related to stock options is included in the following line items in the accompanying unaudited condensed consolidated statements of operations (in thousands): Three Months Ended March 31, 2020 2019 Research and development $ 136 $ 158 Selling, general and administrative 274 334 Total $ 410 $ 492

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Summary of Financial Instruments Measured on a Recurring Basis	The following table summarizes the conclusions reached as of March 31, 2020 and December 31, 2019 for financial instruments measured at fair value on a recurring basis (in thousands): Fair Value Hierarchy Classification Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2020 Cash $ 195 $ 195 — — Restricted cash 273 273 — — Money market funds 20,058 20,058 — — Total assets $ 20,526 $ 20,526 — — Warrant liabilities $ 13,628 — — $ 13,628 Derivative liability 2,492 — — 2,492 Total liabilities $ 16,120 — — $ 16,120 December 31, 2019 Cash $ 23 $ 23 — — Restricted cash 273 273 — — Money market funds 41,897 41,897 — — Total assets $ 42,193 $ 42,193 — — Warrant liabilities $ 18,396 — — $ 18,396 Derivative liability 3,192 — — 3,192 Total liabilities $ 21,588 — — $ 21,588
Reconciliation of liabilities using level 3 inputs	A reconciliation of the beginning and ending balances for liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) is as follows (in thousands): Warrant Liabilities Balance – December 31, 2019 $ 18,396 Gain adjustment to fair value (4,768 ) Balance – March 31, 2020 $ 13,628 Derivative Liability Balance – December 31, 2019 $ 3,192 Gain adjustment to fair value (700 ) Balance – March 31, 2020 $ 2,492

Description of Business and B_2

Description of Business and Basis of Preparation - Additional Information (Detail) - USD ($)	Mar. 31, 2020	Dec. 12, 2019	Sep. 14, 2018	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Accumulated deficit	$ (278,430,000)			$ (278,430,000)		$ (271,428,000)
Cash and cash equivalents	20,253,000			20,253,000		41,920,000
Short-term investments	14,267,000			14,267,000		$ 6,494,000
Shelf registration maximum equity offering price	$ 127,300,000		$ 175,000,000
Number of warrants issued to purchase common stock (in shares)			13,198,075
Aggregate amount receivable upon exercise of warrants			$ 28,600,000
Warrants, expiration date			Mar. 14, 2019
Common stock issued, net of expenses				$ 207,000	$ 2,509,000
Option to Purchase Common Stock
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Options expiration date		2020-01
Option to Purchase Common Stock | Maximum
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of options not exercised		5,833,333
Common Stock
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Common stock issued, net of expenses (in shares)				285,276	2,226,569
Common stock issued, net of expenses				$ 1,000	$ 2,000
Sales Agreement | Common Stock
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Shelf registration maximum equity offering price			$ 25,000,000
June 2016 Public Offering
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of warrants issued to purchase common stock (in shares)			4,218,750
Exercise price of warrants (in dollars per share)			$ 3
March 2018 Public Offering | Series 1 Warrant
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of warrants issued to purchase common stock (in shares)			13,198,075
Exercise price of warrants (in dollars per share)			$ 1.85
March 2018 Public Offering | Series 2 Warrant
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of warrants issued to purchase common stock (in shares)			7,988,175
Exercise price of warrants (in dollars per share)			$ 2
December 2019 Public Offering
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of warrants issued to purchase common stock (in shares)		38,888,889
Common stock issued, net of expenses (in shares)		38,888,889
Share price (in dollars per share)		$ 0.90
Common stock issued, net of expenses		$ 32,500,000
Underwriters | Maximum
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Option to purchase shares of common stock		5,833,333
Underwriters | Warrant liability
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of warrants issued to purchase common stock (in shares)		5,833,333
Number of warrants exercised		5,833,333

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Shares (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	76,980,858	30,769,732
Warrant liability
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	44,722,222	0
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	7,684,762	5,310,498
Outstanding restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	862,514	107,841
Warrants to purchase Series C-1 Preferred | Warrant liability
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	0	14,033
Warrants to purchase common stock associated with Solar loan agreement | Warrant liability
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	122,435	122,435
Warrants to purchase common stock associated with June 2016 Public Offering | Warrant liability
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	4,218,750	4,218,750
March 2018 Public Offering Series 2 [Member] | Warrant liability
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	7,988,175	7,988,175
Common stock associated with 6% convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	11,382,000	13,008,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Shares (Parenthetical) (Details)	Mar. 31, 2020
Common stock associated with 6% convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Interest rate	6.00%

Short-term Investments (Details

Short-term Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 14,267	$ 6,494
Unrealized Gains	18	15
Unrealized Losses	(15)	(14)
Fair Value	14,270	6,495
Commercial paper
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	8,267	998
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	8,267	998
Overnight repurchase agreement
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost		3,500
Unrealized Gains		0
Unrealized Losses		0
Fair Value		3,500
U.S. government securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	6,000	1,996
Unrealized Gains	18	15
Unrealized Losses	(15)	(14)
Fair Value	$ 6,003	$ 1,997

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid research and development services	$ 1,176	$ 3,043
Prepaid insurance	92	252
Other prepaid expenses	88	19
Other current assets	914	674
Total prepaid expenses and other current assets	$ 2,270	$ 3,988

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Accrued research and development expenses	$ 828	$ 1,296
Accrued employee bonus compensation	365	1,798
Other accrued expenses	599	707
Total accrued expenses	$ 1,792	$ 3,801

Borrowings - Additional Informa

Borrowings - Additional Information (Details)	Mar. 07, 2019USD ($)d$ / shares	Sep. 30, 2016USD ($)	Apr. 30, 2019USD ($)shares	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Payment of debt issuance costs				$ 0	$ 1,143,000
Loss on debt extinguishment				0	(814,000)
Convertible debt and derivative liability				11,100,000		$ 11,522,000
Amortization of debt issuance costs and discount				278,000	200,000
Senior Convertible Note Purchase Agreement
Debt Instrument [Line Items]
Face amount	$ 16,000,000
Date of issuance and sale of notes	Mar. 7, 2019
Proceeds from debt, net of issuance costs	$ 14,700,000
Payment of debt issuance costs	$ 1,300,000
Loss on debt extinguishment			$ (200,000)		(800,000)
Reacquisition price of outstanding debt					15,900,000
Carrying value of debt obligation					15,100,000
Senior convertible notes				8,600,000
Unamortized debt issuance cost				500,000
Bifurcated embedded conversion option derivative liability				2,500,000
Derivative, fair value				7,000,000
Debt issuance costs					600,000
Gain (loss) on fair value adjustment of derivative liability				700,000	(3,400,000)
Amortization of debt issuance costs and discount				300,000	$ 200,000
Conversion of convertible note, amount			$ 2,000,000
Conversion of convertible note exchanged for shares | shares			1,626,000
Fair value of convertible debt and derivative liability			$ 2,800,000	$ 10,200,000
Fair value of the consideration issued			$ 3,000,000
Purchase price as percentage of principal amount	100.00%
Interest rate	6.00%
Payment terms				The Notes bear interest at a rate of 6.0% per annum payable semiannually in arrears on March 15 and September 15 of each year, beginning September 15, 2019. The Notes will mature on March 15, 2025, unless earlier converted, redeemed or repurchased.
Notes maturity date	Mar. 15, 2025
Notes maturity description				The Notes will mature on March 15, 2025, unless earlier converted, redeemed or repurchased
Conversion terms				holder of the Notes may convert their Notes at their option at any time prior to the close of business on the business day immediately preceding March 15, 2025 into shares of the Company’s common stock.
Conversion rate, number of shares to be issued per $1000 of principal (in shares)	739.0983
Principal amount of notes used as the denominator for conversion into notes	$ 1,000
Initial conversion price of notes | $ / shares	$ 1.35
Conversion rate, number of shares to be issued per $1000 of principal (in shares) after adjustment to certain events	813
Principal amount of notes used as the denominator for conversion into notes after adjustment of certain events	$ 1,000
Convertible notes, redemption start date	Mar. 15, 2022
Convertible notes, threshold percentage of stock price trigger	130.00%
Convertible notes, threshold trading days | d	20
Convertible notes, threshold consecutive trading days | d	30
Redemption price as percentage of the principal amount	100.00%
Redemption price as percentage of the principal amount subject to certain exceptions	100.00%
Secured Debt | Term Loan
Debt Instrument [Line Items]
Loan agreement term		48 months
Face amount		$ 15,000,000
Secured Debt | Term Loan | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)		8.49%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Mar. 01, 2018USD ($)ft²	Mar. 31, 2020USD ($)
Commitment And Contingencies [Line Items]
Long-term lease agreement, area of office space | ft²	19,275
Lease term	11 years
Total lease payments	$ 7,300,000	$ 167,000
Lessee, operating lease, existence of option to extend	true
Renewal term	5 years
Renewal term, description	The Company has the option to renew for two consecutive five-year periods from the end of the first term and the Company is not reasonably certain that the option to renew the Lease will be exercised. Under the Lease, the Company furnished a security deposit in the form of a standby letter of credit in the amount of $0.3 million, which was reduced by fifty-five thousand dollars on the first anniversary of the commencement date. The security deposit will continue to be reduced by fifty-five thousand dollars every two years on the commencement date anniversary for eight years.
Security deposit in the form of a standby letter of credit	$ 300,000
Decrease in security deposit	$ 55,000
Maximum
Commitment And Contingencies [Line Items]
Milestone payments from the Company		$ 19,000,000

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Quantitative Information Associated with Amounts Recognized in Unaudited Condensed Consolidated Financial Statements for Lease (Detail) - USD ($) $ in Thousands	Mar. 01, 2018	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Operating lease cost		$ 166
Variable lease cost		21
Total operating lease expense		187
Total lease payments	$ 7,300	$ 167
Remaining Lease term (years)		9 years 4 months 2 days
Discount rate		15.00%

Commitments and Contingencies_3

Commitments and Contingencies - Future Minimum Lease Payments (Detail) $ in Thousands	Mar. 31, 2020USD ($)
Commitments And Contingencies Disclosure [Abstract]
2020	$ 340
2021	517
2022	527
2023	715
2024	730
Thereafter	3,533
Total	$ 6,362

Commitments and Contingencies_4

Commitments and Contingencies - Presentation of Operating Lease Liability and Right-of-Use Asset (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Present value of future minimum lease payments	$ 3,312
Operating lease liability, current portion	40	$ 36
Operating lease liability, long-term portion	3,272	3,326
Total operating lease liability	3,312
Difference between future minimum lease payments and discounted cash flows	3,050
Operating lease right-of-use asset	$ 3,143	$ 3,191

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2016	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Sep. 14, 2018
Schedule Of Capitalization Equity [Line Items]
Common stock, par value (in dollars per share)		$ 0.001		$ 0.001
Common stock, shares authorized (in shares)		250,000,000		250,000,000
Common stock, shares issued (in shares)		97,876,042		97,413,721
Common stock, shares outstanding (in shares)		97,876,042		97,413,721
Derivative liability fair value adjustment		$ 700	$ (3,425)
Warrant liabilities fair value adjustment		(4,768)	6,522
Warrant liabilities		13,600
Number of warrants issued to purchase common stock (in shares)					13,198,075
Warrants to purchase common stock associated with Loan Agreement
Schedule Of Capitalization Equity [Line Items]
Number of warrants issued to purchase common stock (in shares)	122,435
Exercise price of warrants (in dollars per share)	$ 3.6754
Warrant expiration period	5 years
Senior Convertible Note Purchase Agreement | Other (Income) Expense
Schedule Of Capitalization Equity [Line Items]
Derivative liability fair value adjustment		$ 700	$ 3,400

Stockholder's Equity - Summary

Stockholder's Equity - Summary of Common Stock Shares Activity (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning balance	$ 12,895	$ 31,225
Beginning balance (in shares)	97,413,721
Net loss	$ (7,002)	(22,908)
Stock-based compensation expense	410	492
Common stock issued through employee stock purchase plan	18	20
Common stock issued, net of expenses	$ 207	2,509
Common stock issued for exercise of stock options (in shares)	0
Common stock issued for vested restricted stock units	$ (73)	(8)
Ending balance	$ 6,455	11,330
Ending balance (in shares)	97,876,042
Common Stock
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning balance	$ 97	$ 48
Beginning balance (in shares)	97,413,721	47,971,989
Net loss	$ 0	$ 0
Stock-based compensation expense	0	0
Common stock issued through employee stock purchase plan	$ 0	$ 0
Common stock issued through employee stock purchase plan (in shares)	22,143	19,259
Common stock issued, net of expenses	$ 1	$ 2
Common stock issued, net of expenses (in shares)	285,276	2,226,569
Common stock issued for vested restricted stock units	$ 0	$ 0
Common stock issued for vested restricted stock units (in shares)	154,902	14,612
Ending balance	$ 98	$ 50
Ending balance (in shares)	97,876,042	50,232,429
Additional Paid-in Capital
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning balance	$ 284,226	$ 248,895
Net loss	0	0
Stock-based compensation expense	410	492
Common stock issued through employee stock purchase plan	18	20
Common stock issued, net of expenses	206	2,507
Common stock issued for vested restricted stock units	(73)	(8)
Ending balance	284,787	251,906
Accumulated Deficit
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning balance	(271,428)	(217,718)
Net loss	(7,002)	(22,908)
Stock-based compensation expense	0	0
Common stock issued through employee stock purchase plan	0	0
Common stock issued, net of expenses	0	0
Common stock issued for vested restricted stock units	0	0
Ending balance	$ (278,430)	$ (240,626)

Stockholder's Equity - Schedule

Stockholder's Equity - Schedule of Reserved Shares of Common Stock for Future Issuance (Detail) - shares	Mar. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Common shares reserved for future issuance	79,278,718	81,439,674
6% Senior Convertible Notes
Class of Stock [Line Items]
Common shares reserved for future issuance	11,382,000	11,382,000
2014 Equity Incentive Plan
Class of Stock [Line Items]
Common shares reserved for future issuance	1,900,861	554,774
2014 Employee Stock Purchase Plan
Class of Stock [Line Items]
Common shares reserved for future issuance	81,499	74,231
2015 Inducement Award Plan
Class of Stock [Line Items]
Common shares reserved for future issuance	315,500	315,500
June 2016 Public Offering | Warrant liability
Class of Stock [Line Items]
Common shares reserved for future issuance	4,218,750	4,218,750
March 2018 Public Offering | Series 2 Warrant
Class of Stock [Line Items]
Common shares reserved for future issuance	7,988,175	7,988,175
December 2019 Public Offering | Warrant liability
Class of Stock [Line Items]
Common shares reserved for future issuance	44,722,222	44,722,222
December 2019 Public Offering | Option to Purchase Common Stock
Class of Stock [Line Items]
Common shares reserved for future issuance	0	5,833,333
Warrants to purchase common stock associated with Solar loan agreement | Warrant liability
Class of Stock [Line Items]
Common shares reserved for future issuance	122,435	122,435
Stock options
Class of Stock [Line Items]
Common shares reserved for future issuance	7,684,762	5,261,860
Restricted Stock Units
Class of Stock [Line Items]
Common shares reserved for future issuance	862,514	966,394

Stock-based Compensation - 2014

Stock-based Compensation - 2014 Equity Incentive Plan (Details) - 2014 Equity Incentive Plan - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of additional shares authorized	3,896,548	1,918,879
Possible future issuance under equity compensation plan (in shares)	1,900,861

Stock-based Compensation - 2015

Stock-based Compensation - 2015 Inducement Award Plan (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted (shares)	2,563,400
2015 Inducement Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Possible future issuance under equity compensation plan (in shares)	315,500
Granted (shares)	0	0

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Number of Shares
Beginning balance - Outstanding (shares)	5,261,860
Granted (shares)	2,563,400
Exercised (shares)	0
Forfeited/Cancelled(shares)	(140,498)
Ending balance - Outstanding (shares)	7,684,762	5,261,860
Exercisable (shares)	3,326,023
Vested or expected to vest (shares)	7,684,762
Weighted- Average Exercise Price
Beginning balance - Outstanding (in dollars per share)	$ 3.06
Granted (in dollars per share)	0.86
Exercised (in dollars per share)	0
Forfeited/Cancelled (in dollars per share)	1.80
Ending balance - Outstanding (in dollars per share)	2.35	$ 3.06
Exercisable (in dollars per share)	3.89
Vested or expected to vest (in dollars per share)	$ 2.35
Weighted- Average Remaining Contractual Life (in years)
Balance - Outstanding	8 years 1 month 9 days	7 years 7 months 13 days
Exercisable	6 years 7 months 17 days
Vested or expected to vest	8 years 1 month 9 days
Aggregate Intrinsic Value ($000)
Balance - Outstanding	$ 28	$ 60
Exercisable	23
Vested and expected to vest	$ 28

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Restricted Stock Units ("RSU") Activity (Details) - Restricted Stock Units	3 Months Ended
	Mar. 31, 2020$ / sharesshares
Number of Shares
Beginning balance - Outstanding (shares) | shares	966,394
Options granted in period (shares) | shares	256,950
Vested (shares) | shares	(231,439)
Forfeited/Cancelled (shares) | shares	(129,391)
Ending balance - Outstanding (shares) | shares	862,514
Weighted Average Grant Date Fair Value Per Share
Beginning balance - Outstanding (in dollars per share) | $ / shares	$ 1.42
Granted (in dollars per share) | $ / shares	0.86
Vested (in dollars per share) | $ / shares	1.46
Forfeited/Cancelled dollars per share) | $ / shares	1.26
Ending balance - Outstanding (in dollars per share) | $ / shares	$ 1.26
Vesting percentage	25.00%
Vesting period of options	4 years

Stock-based Compensation - Comp

Stock-based Compensation - Compensation Cost (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based compensation expense	$ 410,000	$ 492,000
Tax benefit from compensation expense	0	0
Cash received from option exercised	$ 0	$ 0

Stock-based Compensation - Expe

Stock-based Compensation - Expense Related to Stock Options (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense related to stock options	$ 410	$ 492
Research and development, net
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense related to stock options	136	158
Selling, general and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense related to stock options	$ 274	$ 334

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Instruments Measured on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	$ 20,526	$ 42,193
Fair value of financial liabilities	16,120	21,588
Warrant liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	13,628	18,396
Derivative liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	2,492	3,192
Cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	195	23
Restricted cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	273	273
Money market funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	20,058	41,897
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	20,526	42,193
Fair value of financial liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Warrant liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Derivative liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	195	23
Quoted Prices in Active Markets for Identical Assets (Level 1) | Restricted cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	273	273
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	20,058	41,897
Significant Other Observable Inputs (Level 2)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	0	0
Fair value of financial liabilities	0	0
Significant Other Observable Inputs (Level 2) | Warrant liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	0	0
Significant Other Observable Inputs (Level 2) | Derivative liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	0	0
Significant Other Observable Inputs (Level 2) | Cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	0	0
Significant Other Observable Inputs (Level 2) | Restricted cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	0	0
Significant Other Observable Inputs (Level 2) | Money market funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	0	0
Significant Unobservable Inputs (Level 3)
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	0	0
Fair value of financial liabilities	16,120	21,588
Significant Unobservable Inputs (Level 3) | Warrant liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	13,628	18,396
Significant Unobservable Inputs (Level 3) | Derivative liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	2,492	3,192
Significant Unobservable Inputs (Level 3) | Cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	0	0
Significant Unobservable Inputs (Level 3) | Restricted cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	0	0
Significant Unobservable Inputs (Level 3) | Money market funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	$ 0	$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - Level 3	Mar. 31, 2020	Dec. 31, 2019
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Warrant liabilities, maturity date	Jun. 12, 2023
Stock Price Volatility
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative liabilities, unobservable inputs rate	56.8
Stock Price Volatility | Minimum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Warrant liabilities, stock price volatility rate	73.7
Stock Price Volatility | Maximum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Warrant liabilities, stock price volatility rate	78.4
Stock Price Volatility | Weighted Average
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Warrant liabilities, stock price volatility rate	75
Weighted Average Expected Term
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Warrant liabilities, expected term	2 years 7 months 6 days
Weighted Average Expected Term | Minimum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Warrant liabilities, expected term		1 year 7 months 6 days
Weighted Average Expected Term | Maximum
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Warrant liabilities, expected term		3 years 2 months 12 days
Market Credit Spread
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative liabilities, unobservable inputs rate	2,063
Estimated Yield
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Derivative liabilities, unobservable inputs rate	21
Discounts for Lack of Marketability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Senior convertible notes, unobservable inputs rate	12.07

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Reconciliation of Beginning and Ending Balances for Liabilities Measured at Fair Value on Recurring Basis (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020USD ($)
Warrant liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 18,396
Gain adjustment to fair value	(4,768)
Ending balance	13,628
Derivative liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	3,192
Gain adjustment to fair value	(700)
Ending balance	$ 2,492

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Subsequent Event - USD ($)	Apr. 09, 2020	Apr. 30, 2020
New Jersey
Subsequent Event [Line Items]
Proceeds from sale of net operating loss and research and development tax credit carryforwards		$ 3,100,000
NOLs and Research and Development Credits
Subsequent Event [Line Items]
Income tax benefit		$ 3,100,000
Maximum | Nasdaq Global Market
Subsequent Event [Line Items]
Common stock, closing bid price per share		$ 1
Common Stock Purchase Agreement | Aspire Capital | Maximum
Subsequent Event [Line Items]
Sale of common stock at sole discretion		$ 20,000,000
6.0% Senior Convertible Notes due 2026 | April 2020 Note Purchase Agreement
Subsequent Event [Line Items]
Date of issuance and sale of notes	Apr. 9, 2020
Face amount	$ 10,000,000
Interest rate	6.00%