SCYNEXIS (SCYX) 10-Q 8 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 01, 2019
Document And Entity Information [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	true
Entity Ex Transition Period	true
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		53,651,269

Unaudited Condensed Balance She

Unaudited Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 12,950	$ 11,439
Short-term investments	26,110	32,718
Prepaid expenses and other current assets	958	7,251
Restricted cash	55	55
Total current assets	40,073	51,463
Other assets	812	812
Deferred offering costs	104	106
Restricted cash	273	273
Property and equipment, net	488	516
Operating lease right-of-use asset (See Note 7)	3,317	0
Total assets	45,067	53,170
Current liabilities:
Accounts payable	2,346	3,653
Accrued expenses	2,211	2,103
Deferred revenue	54	121
Operating lease liability, current portion (See Note 7)	27	0
Total current liabilities	4,638	5,877
Warrant liabilities	7,508	986
Loan payable expected to be refinanced	0	15,082
Convertible debt and derivative liability (See Note 6)	18,296	0
Operating lease liability (See Note 7)	3,295	0
Total liabilities	33,737	21,945
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value, authorized 5,000,000 shares as of March 31, 2019 and December 31, 2018; 0 shares issued and outstanding as of March 31, 2019 and December 31, 2018	0	0
Common stock, $0.001 par value, 125,000,000 shares authorized as of March 31, 2019, and December 31, 2018; 50,232,429 and 47,971,989 shares issued and outstanding as of March 31, 2019, and December 31, 2018, respectively	50	48
Additional paid-in capital	251,906	248,895
Accumulated deficit	(240,626)	(217,718)
Total stockholders’ equity	11,330	31,225
Total liabilities and stockholders’ equity	$ 45,067	$ 53,170

Unaudited Condensed Balance S_2

Unaudited Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
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)	125,000,000	125,000,000
Common stock, shares issued (in shares)	50,232,429	47,971,989
Common stock, shares outstanding (in shares)	50,232,429	47,971,989

Unaudited Condensed Statements

Unaudited Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenue	$ 64	$ 64
Operating expenses:
Research and development	9,684	5,326
Selling, general and administrative	2,241	1,971
Total operating expenses	11,925	7,297
Loss from operations:	(11,861)	(7,233)
Other (income) expense:
Loss on extinguishment of debt	814	0
Amortization of debt issuance costs and discount	200	111
Interest income	(281)	(167)
Interest expense	367	379
Warrant liabilities fair value adjustment	6,522	(3,554)
Derivative liability fair value adjustment	3,425	0
Total other expense (income):	11,047	(3,231)
Net loss	$ (22,908)	$ (4,002)
Net loss per share - basic and diluted	$ (0.46)	$ (0.12)
Weighted average common shares outstanding - basic and diluted	49,317,575	33,579,025

Unaudited Condensed Statement_2

Unaudited Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (22,908)	$ (4,002)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	29	1
Stock-based compensation expense	492	425
Accretion of investment discount	(82)	(58)
Amortization of debt issuance costs and discount	200	111
Change in fair value of warrant liabilities	6,522	(3,554)
Change in fair value of derivative liability	3,425	0
Amortization of operating lease right-of-use asset	48	0
Loss on extinguishment of debt	814	0
Changes in operating assets and liabilities:
Prepaid expenses, other assets, and deferred costs	6,390	422
Accounts payable and accrued expenses	(1,367)	(1,500)
Deferred revenue	(64)	(64)
Net cash used in operating activities	(6,501)	(8,219)
Cash flows from investing activities:
Maturities of investments	24,638	11,980
Purchases of property and equipment	0	(10)
Purchases of investments	(18,041)	(15,975)
Net cash provided by (used in) investing activities	6,597	(4,005)
Cash flows from financing activities:
Proceeds from common stock issued	2,588	30,192
Payments of offering costs and underwriting discounts and commissions	(77)	(1,906)
Proceeds from employee stock purchase plan issuance	20	20
Proceeds from senior convertible notes	16,000	0
Payments of senior convertible notes issuance costs	(1,143)	0
Payment of loan payable expected to be refinanced	(15,973)	0
Net cash provided by financing activities	1,415	28,306
Net increase in cash, cash equivalents, and restricted cash	1,511	16,082
Cash, cash equivalents, and restricted cash at beginning of period	11,767	11,469
Cash, cash equivalents, and restricted cash at end of period	13,278	27,551
Supplemental cash flow information:
Cash paid for interest	411	379
Cash received for interest	291	128
Noncash financing and investing activities:
Operating lease liabilities arising from obtaining right-of-use assets	3,365	0
Deferred offering and issuance costs included in accounts payable and accrued expenses	110	224
Deferred offering costs reclassified to additional-paid-in capital	$ 2	$ 84

Description of Business and Bas

Description of Business and Basis of Preparation	3 Months Ended
	Mar. 31, 2019
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, committed to positively impacting the lives of patients suffering from difficult-to-treat and often life-threatening infections by delivering innovative therapies. The Company is developing its lead product candidate, ibrexafungerp, as the first representative of a novel oral and intravenous triterpenoid antifungal family for the treatment of several fungal infections, including serious and life-threatening invasive fungal infections. The Company has incurred losses and negative cash flows from operations since its initial public offering ("IPO") in May 2014 and expects to continue to incur losses. The Company's liquidity over the next 12 months could be materially affected by, among other things: its ability to raise capital through equity offerings, debt financings, other non-dilutive third-party funding (e.g., grants), strategic alliances and licensing or collaboration arrangements; key ibrexafungerp development and regulatory events; costs related to its development of ibrexafungerp; and other factors. Shelf Registration Filing On August 31, 2018, the Company filed a shelf registration statement on Form S-3 (File No. 333-227167) with the 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, 2019, the holders of the warrants would pay the Company an aggregate of approximately $28.6 million. See Note 8 for further details. 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. Unaudited Interim Financial Information The accompanying unaudited financial statements and notes have been prepared in accordance with accounting principles generally accepted in the United States, or 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, 2019, are not necessarily indicative of the results for the full year or the results for any future periods. These interim 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 14, 2019. Use of Estimates The preparation of 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, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. The accompanying unaudited 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, 2018, 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 FASB 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 all periods as the result would be anti-dilutive: Three Months Ended March 31, 2019 2018 Warrants to purchase Series C-1 Preferred 14,033 14,033 Warrants to purchase common stock associated with Solar Capital Ltd. 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 1 — 13,313,625 Warrants to purchase common stock associated with March 2018 public offering - Series 2 7,988,175 7,988,175 Stock options 5,310,498 4,152,734 Common stock associated with 6% convertible senior notes 13,008,000 — Convertible Debt and Derivative Liability In connection with the Company’s issuance of its 6.0% Convertible Senior Notes due 2025 (the “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 convertible debt and the derivative liability associated with the Notes are presented in total on the unaudited balance sheet as the convertible debt and derivative liability. The convertible debt is carried at amortized cost. 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). Amortization of Debt Issuance Costs and Discount The Company’s convertible debt is recorded net of debt issuance costs which comprised issuance costs and an advisory fee. The portion of the debt issuance costs allocated to the convertible debt, based on the amount of proceeds allocated between the convertible debt and the derivative liability, is being amortized over the term of the convertible debt using the effective interest method. Debt issuance costs allocated to the derivative liability were included in other expense as a component of the fair value adjustment for the three months ended March 31, 2019. The Company's previous term loan with Solar Capital Ltd. (“Solar”), which was paid in full during the three months ended March 31, 2019 (see Note 6), was recorded net of debt discount which comprised issuance costs, customary closing and final fees, and the fair value of the warrants issued in conjunction with the term loan. The resulting debt discount was being amortized over the term of the term loan using the straight-line method, which approximates the effective interest method. The amortization of debt issuance costs and discount is included in the accompanying unaudited statements of operations. Recently Adopted Accounting Pronouncements The Company adopted the FASB’s ASU No. 2016-02, Leases, or ASU 2016-02, on January 1, 2019, utilizing the modified retrospective basis. ASU 2016-02 requires lessees to recognize a right-of-use asset and lease liability, initially measured at the present value of future lease payments, on the balance sheet and expands disclosure requirements regarding leasing arrangements. The Company elected the practical expedients under ASC 842-10-65-1(f) and ASC 842-10-15-37 that allowed the Company to forego the requirement to reassess the lease classification of its existing office lease and to combine the lease and nonlease components associated with its office lease as a single lease component. The consideration in the office lease that is 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 office 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 adoption of this accounting standard did not materially impact the Company’s results of operations, other than the recognition of the operating lease right-of-use asset and lease liability. See Note 7 for further details.

Short-term Investments

Short-term Investments	3 Months Ended
	Mar. 31, 2019
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, 2019 and December 31, 2018 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2018 U.S. government securities $ 14,946 $ 14 $ (15 ) $ 14,945 Commercial paper 8,772 — — 8,772 Overnight repurchase agreement 9,000 — — 9,000 Total short-term investments $ 32,718 $ 14 $ (15 ) $ 32,717 Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of March 31, 2019 U.S. government securities $ 13,430 $ 5 $ (4 ) $ 13,431 Commercial paper 7,680 — — 7,680 Overnight repurchase agreement 5,000 — — 5,000 Total short-term investments $ 26,110 $ 5 $ (4 ) $ 26,111 All held-to-maturity short-term investments at March 31, 2019 and December 31, 2018 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, 2019
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, 2019 December 31, 2018 Prepaid research and development services $ 743 $ 245 Prepaid insurance 92 200 Other prepaid expenses 68 20 NOL sale receivable — 6,732 Other current assets 55 54 Total prepaid expenses and other current assets $ 958 $ 7,251

Accrued Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2019
Payables And Accruals [Abstract]
Accrued Expenses	5. Accrued Expenses Accrued expenses consisted of the following (in thousands): March 31, 2019 December 31, 2018 Accrued research and development expenses $ 1,444 $ 587 Accrued employee bonus compensation 325 1,197 Employee withholdings 7 21 Other accrued expenses 435 298 Total accrued expenses $ 2,211 $ 2,103

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Borrowings	6. Borrowings On September 30, 2016, the Company entered into a loan agreement with 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%. On March 7, 2019, the Company entered into a Senior Convertible Note Purchase Agreement (the “Note Purchase Agreement”) with Puissance Life Science Opportunities Fund VI (“Puissance”). Pursuant to the Note Purchase Agreement, on March 7, 2019, the Company issued and sold to Puissance $16.0 million aggregate principal amount of its 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 In accordance with ASC 470-10-45-14(a), the Company reclassified the short-term portion of the Solar term loan on the balance sheet as of December 31, 2018 to long-term given the Company had the intent and ability to refinance the short-term obligation on a long-term basis . As of March 31, 2019, the Company's $18.3 million in convertible debt and derivative liability consists of the convertible debt balance of $8.5 million presented net of the unamortized debt issuance costs allocated to the convertible debt of $0.6 million and the bifurcated embedded conversion option derivative liability of $9.8 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, at its initial fair value of $7.0 million as the interest make-whole provision is settled in shares of common stock. Debt issuance costs of $0.6 million initially allocated to the derivative liability were written off upon issuance of the Notes and were recognized in the loss on the fair value adjustment for the derivative liability for the three months ended March 31, 2019. For the three months ended March 31, 2019, the Company recognized a $2.9 million loss on the fair value adjustment for the derivative liability and recognized $0.1 million in amortization of debt issuance costs. 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, 2019, the fair value of the senior convertible notes is $19.1 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 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. In April 2019, Puissance converted $2.0 million of the Notes for 1,626,000 shares of common stock. 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 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, 2019
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 must furnish a security deposit in the form of a standby letter of credit in the amount of $0.3 million, which will be reduced by fifty-five thousand dollars every two years for ten years after the commencement of the lease. The security deposit is classified as restricted cash in the accompanying balance sheets . On January 1, 2019, a right-of-use asset and a corresponding operating lease liability of $3.4 million was recognized for the Lease. 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. In determining the operating lease liability at January 1, 2019, the Company utilized its incremental borrowing rate. The incremental borrowing rate 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 financial statements for the Lease (dollars in thousands): Three Months Ended March 31, 2019 Operating lease cost $ 166 Variable lease cost $ 9 Total operating lease expense $ 175 Cash paid for amounts included in the measurement of operating lease liability $ 164 March 31, 2019 Remaining Lease term (years) 10.25 Discount rate 15 % Rent expense was approximately $0.1 million for the three months ended March 31, 2018. Future minimum lease payments for the Lease as of March 31, 2019 and December 31, 2018 are as follows (in thousands): December 31, 2018 2019 498 2020 508 2021 518 2022 529 2023 716 Thereafter 4,203 Total $ 6,972 March 31, 2019 2019 334 2020 508 2021 518 2022 529 2023 716 Thereafter 4,203 Total $ 6,808 The presentation of the operating lease liability and right-of-use asset as of March 31, 2019 and January 1, 2019 are as follows (in thousands): March 31, 2019 January 1, 2019 Present value of future minimum lease payments $ 3,322 $ 3,368 Operating lease liability, current portion $ 27 $ 23 Operating lease liability, long-term portion $ 3,295 $ 3,345 Total operating lease liability $ 3,322 $ 3,368 Difference between future minimum lease payments and discounted cash flows $ 3,486 $ 3,604 Operating lease right-of-use asset $ 3,317 $ 3,365 License Arrangement with Potential Future Expenditures As of March 31, 2019, 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 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. The Company has two additional licensing agreements for other compounds that could require it to make payments of up to $2.3 million upon achievement of certain milestones by the Company. 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, 2019
Equity [Abstract]
Stockholder's Equity	8. Stockholder's 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 125,000,000 shares as of March 31, 2019, and December 31, 2018; 50,232,429 and 47,971,989 shares were issued and outstanding at March 31, 2019, and December 31, 2018, respectively. The following table summarizes common stock share activity for the three months ended March 31, 2019 and 2018 (dollars in thousands): Three Months Ended March 31, 2018 Shares of Common Stock Common Stock Additional Paid-in Capital Accumulated Deficit Total Stockholders' Equity Balance, January 1, 2018 28,971,651 $ 29 $ 226,631 $ (205,250 ) $ 21,410 Net loss — — — (4,002 ) (4,002 ) Stock-based compensation expense — — 425 — 425 Common stock issued through employee stock purchase plan 13,591 — 20 — 20 Common stock issued, net of expenses 17,852,193 18 18,980 — 18,998 Common stock issued for vested restricted stock units 6,006 — (7 ) — (7 ) Balance, March 31, 2018 46,843,441 $ 47 $ 246,049 $ (209,252 ) $ 36,844 Three Months Ended March 31, 2019 Shares of Common Stock Common Stock Additional Paid-in Capital Accumulated Deficit Total Stockholders' Equity Balance, January 1, 2019 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, 2019 December 31, 2018 Outstanding stock options 5,310,498 4,052,913 Outstanding restricted stock units 990,301 111,891 Outstanding Series C-1 Preferred warrants 14,033 14,033 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 1 — 13,198,075 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 Loan Agreement 122,435 122,435 For possible future issuance for the conversion of the 6% senior convertible notes 13,008,000 — For possible future issuance under 2014 Equity Incentive Plan (Note 9) 372,312 612,018 For possible future issuance under Employee Stock Purchase Plan (Note 9) 91,819 81,667 For possible future issuance under 2015 Inducement Plan (Note 9) 5,000 5,000 Total common shares reserved for future issuance 32,121,323 30,404,957 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 convertible debt and derivative liability associated with the Notes are presented in total on the accompanying unaudited balance sheet as the convertible debt and derivative liability. In April 2019, Puissance converted $2.0 million of the Notes for 1,626,000 shares of common stock. Warrants Associated with June 2016 and March 2018 Public Offerings The outstanding warrants associated with the June 2016 and March 2018 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 Pursuant to the loan agreement, on the Closing Date the Company issued to Solar the warrant to purchase an aggregate of up to 122,435 shares of the Company’s common stock at an exercise price of $3.6754 per share. The warrant will expire five years from the date of the grant. The warrant was classified as equity and recorded at its relative fair value at issuance in the stockholders' equity section of the balance sheet.

Stock-based Compensation

Stock-based Compensation	3 Months Ended
	Mar. 31, 2019
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, or 2014 Plan, on January 1, 2019 and 2018, the Company automatically added 1,918,879 and 1,158,866 shares to the total number shares of common stock available for future issuance under the 2014 Plan, respectively. As of March 31, 2019, there were 372,312 shares of common stock available for future issuance under the 2014 Plan. The activity for the Company’s 2009 Stock Option Plan, 2014 Plan and 2015 Inducement Plan, or 2015 Plan, for the three months ended March 31, 2019, is summarized as follows: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in years) Aggregate Intrinsic Value ($000) Outstanding — January 1, 2019 4,052,913 $ 4.37 7.23 $ — Granted 1,270,500 $ 1.26 Exercised — $ — Forfeited/Cancelled (12,915 ) $ 9.35 Outstanding — March 31, 2019 5,310,498 $ 3.62 7.69 $ 333 Exercisable — March 31, 2019 2,621,464 $ 5.43 6.29 $ 13 Vested or expected to vest — March 31, 2019 5,310,498 $ 3.62 7.69 $ 333 Restricted stock unit ("RSU") activity under the 2014 Plan for the three months ended March 31, 2019, is summarized as follows: Number of Shares Weighted Average Grant Date Fair Value Per Share Non-vested at December 31, 2018 111,891 $ 2.06 Granted 901,000 $ 1.38 Vested (22,590 ) $ 2.30 Forfeited/Cancelled — $ — Non-vested at March 31, 2019 990,301 $ 1.43 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 2009 Stock Option Plan, the 2014 Plan, the 2015 Plan, and the Company’s 2014 Employee Stock Purchase Plan, or ESPP, was $0.5 million and $0.4 million for the three months ended March 31, 2019 and 2018, respectively. The total income tax benefit recognized in the statements of operations for share-based compensation arrangements was zero for the three months ended March 31, 2019 and 2018. Cash received from options exercised was zero for the three months ended March 31, 2019, and 2018. Stock-based compensation expense related to stock options is included in the following line items in the accompanying statements of operations (in thousands): Three Months Ended March 31, 2019 2018 Research and development $ 158 $ 108 Selling, general and administrative 334 317 Total $ 492 $ 425

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2019
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, 2019 and December 31, 2018 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) December 31, 2018 Cash $ 213 $ 213 — — Restricted cash 328 328 — — Money market funds 11,226 11,226 — — Total assets $ 11,767 $ 11,767 — — Warrant liabilities $ 986 — — $ 986 Total liabilities $ 986 — — $ 986 March 31, 2019 Restricted cash $ 328 $ 328 — — Money market funds 12,950 12,950 — — Total assets $ 13,278 $ 13,278 — — Warrant liabilities $ 7,508 — — $ 7,508 Derivative liability $ 9,840 — — $ 9,840 Total liabilities $ 17,348 — — $ 17,348 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 liability 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 liability 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 Company uses the binomial lattice valuation model to value the Level 3 derivative liability at inception and on subsequent valuation dates. 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 - January 1, 2019 $ 986 Loss adjustment to fair value 6,522 Balance - March 31, 2019 $ 7,508 Derivative Liability Balance - January 1, 2019 $ — Bifurcated embedded conversion option associated with Notes 6,960 Loss adjustment to fair value 2,880 Balance - March 31, 2019 $ 9,840

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
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 FASB 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 all periods as the result would be anti-dilutive: Three Months Ended March 31, 2019 2018 Warrants to purchase Series C-1 Preferred 14,033 14,033 Warrants to purchase common stock associated with Solar Capital Ltd. 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 1 — 13,313,625 Warrants to purchase common stock associated with March 2018 public offering - Series 2 7,988,175 7,988,175 Stock options 5,310,498 4,152,734 Common stock associated with 6% convertible senior notes 13,008,000 —
Convertible Debt and Derivative Liability	Convertible Debt and Derivative Liability In connection with the Company’s issuance of its 6.0% Convertible Senior Notes due 2025 (the “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 convertible debt and the derivative liability associated with the Notes are presented in total on the unaudited balance sheet as the convertible debt and derivative liability. The convertible debt is carried at amortized cost. 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).
Amortization of Debt Issuance Costs and Discount	Amortization of Debt Issuance Costs and Discount The Company’s convertible debt is recorded net of debt issuance costs which comprised issuance costs and an advisory fee. The portion of the debt issuance costs allocated to the convertible debt, based on the amount of proceeds allocated between the convertible debt and the derivative liability, is being amortized over the term of the convertible debt using the effective interest method. Debt issuance costs allocated to the derivative liability were included in other expense as a component of the fair value adjustment for the three months ended March 31, 2019. The Company's previous term loan with Solar Capital Ltd. (“Solar”), which was paid in full during the three months ended March 31, 2019 (see Note 6), was recorded net of debt discount which comprised issuance costs, customary closing and final fees, and the fair value of the warrants issued in conjunction with the term loan. The resulting debt discount was being amortized over the term of the term loan using the straight-line method, which approximates the effective interest method. The amortization of debt issuance costs and discount is included in the accompanying unaudited statements of operations.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements The Company adopted the FASB’s ASU No. 2016-02, Leases, or ASU 2016-02, on January 1, 2019, utilizing the modified retrospective basis. ASU 2016-02 requires lessees to recognize a right-of-use asset and lease liability, initially measured at the present value of future lease payments, on the balance sheet and expands disclosure requirements regarding leasing arrangements. The Company elected the practical expedients under ASC 842-10-65-1(f) and ASC 842-10-15-37 that allowed the Company to forego the requirement to reassess the lease classification of its existing office lease and to combine the lease and nonlease components associated with its office lease as a single lease component. The consideration in the office lease that is 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 office 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 adoption of this accounting standard did not materially impact the Company’s results of operations, other than the recognition of the operating lease right-of-use asset and lease liability. See Note 7 for further details.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2019
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 all periods as the result would be anti-dilutive: Three Months Ended March 31, 2019 2018 Warrants to purchase Series C-1 Preferred 14,033 14,033 Warrants to purchase common stock associated with Solar Capital Ltd. 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 1 — 13,313,625 Warrants to purchase common stock associated with March 2018 public offering - Series 2 7,988,175 7,988,175 Stock options 5,310,498 4,152,734 Common stock associated with 6% convertible senior notes 13,008,000 —

Short-term Investments (Tables)

Short-term Investments (Tables)	3 Months Ended
	Mar. 31, 2019
Investments Debt And Equity Securities [Abstract]
Held-to-maturity Securities	The following table summarizes the held-to-maturity securities held at March 31, 2019 and December 31, 2018 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of December 31, 2018 U.S. government securities $ 14,946 $ 14 $ (15 ) $ 14,945 Commercial paper 8,772 — — 8,772 Overnight repurchase agreement 9,000 — — 9,000 Total short-term investments $ 32,718 $ 14 $ (15 ) $ 32,717 Amortized Cost Unrealized Gains Unrealized Losses Fair Value As of March 31, 2019 U.S. government securities $ 13,430 $ 5 $ (4 ) $ 13,431 Commercial paper 7,680 — — 7,680 Overnight repurchase agreement 5,000 — — 5,000 Total short-term investments $ 26,110 $ 5 $ (4 ) $ 26,111

Prepaid Expenses and Other Cu_2

Prepaid Expenses and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 2019
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, 2019 December 31, 2018 Prepaid research and development services $ 743 $ 245 Prepaid insurance 92 200 Other prepaid expenses 68 20 NOL sale receivable — 6,732 Other current assets 55 54 Total prepaid expenses and other current assets $ 958 $ 7,251

Accrued Expenses (Tables)

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2019
Payables And Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following (in thousands): March 31, 2019 December 31, 2018 Accrued research and development expenses $ 1,444 $ 587 Accrued employee bonus compensation 325 1,197 Employee withholdings 7 21 Other accrued expenses 435 298 Total accrued expenses $ 2,211 $ 2,103

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Summary of Quantitative Information Associated with Amounts Recognized in Financial Statements for Lease	The following table summarizes certain quantitative information associated with the amounts recognized in the financial statements for the Lease (dollars in thousands): Three Months Ended March 31, 2019 Operating lease cost $ 166 Variable lease cost $ 9 Total operating lease expense $ 175 Cash paid for amounts included in the measurement of operating lease liability $ 164 March 31, 2019 Remaining Lease term (years) 10.25 Discount rate 15 %
Future Minimum Lease Payments	Future minimum lease payments for the Lease as of March 31, 2019 and December 31, 2018 are as follows (in thousands): December 31, 2018 2019 498 2020 508 2021 518 2022 529 2023 716 Thereafter 4,203 Total $ 6,972 March 31, 2019 2019 334 2020 508 2021 518 2022 529 2023 716 Thereafter 4,203 Total $ 6,808
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, 2019 and January 1, 2019 are as follows (in thousands): March 31, 2019 January 1, 2019 Present value of future minimum lease payments $ 3,322 $ 3,368 Operating lease liability, current portion $ 27 $ 23 Operating lease liability, long-term portion $ 3,295 $ 3,345 Total operating lease liability $ 3,322 $ 3,368 Difference between future minimum lease payments and discounted cash flows $ 3,486 $ 3,604 Operating lease right-of-use asset $ 3,317 $ 3,365

Stockholder's Equity (Tables)

Stockholder's Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Summary of Common Stock Shares Activity	The following table summarizes common stock share activity for the three months ended March 31, 2019 and 2018 (dollars in thousands): Three Months Ended March 31, 2018 Shares of Common Stock Common Stock Additional Paid-in Capital Accumulated Deficit Total Stockholders' Equity Balance, January 1, 2018 28,971,651 $ 29 $ 226,631 $ (205,250 ) $ 21,410 Net loss — — — (4,002 ) (4,002 ) Stock-based compensation expense — — 425 — 425 Common stock issued through employee stock purchase plan 13,591 — 20 — 20 Common stock issued, net of expenses 17,852,193 18 18,980 — 18,998 Common stock issued for vested restricted stock units 6,006 — (7 ) — (7 ) Balance, March 31, 2018 46,843,441 $ 47 $ 246,049 $ (209,252 ) $ 36,844 Three Months Ended March 31, 2019 Shares of Common Stock Common Stock Additional Paid-in Capital Accumulated Deficit Total Stockholders' Equity Balance, January 1, 2019 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, 2019 December 31, 2018 Outstanding stock options 5,310,498 4,052,913 Outstanding restricted stock units 990,301 111,891 Outstanding Series C-1 Preferred warrants 14,033 14,033 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 1 — 13,198,075 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 Loan Agreement 122,435 122,435 For possible future issuance for the conversion of the 6% senior convertible notes 13,008,000 — For possible future issuance under 2014 Equity Incentive Plan (Note 9) 372,312 612,018 For possible future issuance under Employee Stock Purchase Plan (Note 9) 91,819 81,667 For possible future issuance under 2015 Inducement Plan (Note 9) 5,000 5,000 Total common shares reserved for future issuance 32,121,323 30,404,957

Stock-based Compensation (Table

Stock-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
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 Inducement Plan, or 2015 Plan, for the three months ended March 31, 2019, is summarized as follows: Number of Shares Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (in years) Aggregate Intrinsic Value ($000) Outstanding — January 1, 2019 4,052,913 $ 4.37 7.23 $ — Granted 1,270,500 $ 1.26 Exercised — $ — Forfeited/Cancelled (12,915 ) $ 9.35 Outstanding — March 31, 2019 5,310,498 $ 3.62 7.69 $ 333 Exercisable — March 31, 2019 2,621,464 $ 5.43 6.29 $ 13 Vested or expected to vest — March 31, 2019 5,310,498 $ 3.62 7.69 $ 333
Schedule of Restricted Stock Units ("RSU") Activity	Restricted stock unit ("RSU") activity under the 2014 Plan for the three months ended March 31, 2019, is summarized as follows: Number of Shares Weighted Average Grant Date Fair Value Per Share Non-vested at December 31, 2018 111,891 $ 2.06 Granted 901,000 $ 1.38 Vested (22,590 ) $ 2.30 Forfeited/Cancelled — $ — Non-vested at March 31, 2019 990,301 $ 1.43
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 statements of operations (in thousands): Three Months Ended March 31, 2019 2018 Research and development $ 158 $ 108 Selling, general and administrative 334 317 Total $ 492 $ 425

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Summary of Financial Instruments Measured on a Recurring Basis	The following table summarizes the conclusions reached as of March 31, 2019 and December 31, 2018 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) December 31, 2018 Cash $ 213 $ 213 — — Restricted cash 328 328 — — Money market funds 11,226 11,226 — — Total assets $ 11,767 $ 11,767 — — Warrant liabilities $ 986 — — $ 986 Total liabilities $ 986 — — $ 986 March 31, 2019 Restricted cash $ 328 $ 328 — — Money market funds 12,950 12,950 — — Total assets $ 13,278 $ 13,278 — — Warrant liabilities $ 7,508 — — $ 7,508 Derivative liability $ 9,840 — — $ 9,840 Total liabilities $ 17,348 — — $ 17,348
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 - January 1, 2019 $ 986 Loss adjustment to fair value 6,522 Balance - March 31, 2019 $ 7,508 Derivative Liability Balance - January 1, 2019 $ — Bifurcated embedded conversion option associated with Notes 6,960 Loss adjustment to fair value 2,880 Balance - March 31, 2019 $ 9,840

Description of Business and B_2

Description of Business and Basis of Preparation - Additional Information (Detail)	Sep. 14, 2018USD ($)$ / sharesshares
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Shelf registration maximum equity offering price | $	$ 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
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) | $ / shares	$ 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) | $ / shares	$ 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) | $ / shares	$ 2

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Shares (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	5,310,498	4,152,734
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)	14,033	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 1 [Member] | Warrant liability
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities (in shares)	0	13,313,625
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)	13,008,000	0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Shares (Parenthetical) (Details)	Mar. 31, 2019
Common stock associated with 6% convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Interest rate	6.00%

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Additional Information (Detail)	Mar. 31, 2019
6.0% Convertible Senior Notes due 2025
Subsidiary Sale Of Stock [Line Items]
Interest rate	6.00%

Short-term Investments (Details

Short-term Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 26,110	$ 32,718
Unrealized Gains	5	14
Unrealized Losses	(4)	(15)
Fair Value	26,111	32,717
Commercial paper
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	7,680	8,772
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	7,680	8,772
Overnight repurchase agreement
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	5,000	9,000
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	5,000	9,000
U.S. government securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	13,430	14,946
Unrealized Gains	5	14
Unrealized Losses	(4)	(15)
Fair Value	$ 13,431	$ 14,945

Prepaid Expenses and Other Cu_3

Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid research and development services	$ 743	$ 245
Prepaid insurance	92	200
Other prepaid expenses	68	20
NOL sale receivable	0	6,732
Other current assets	55	54
Total prepaid expenses and other current assets	$ 958	$ 7,251

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued research and development expenses	$ 1,444	$ 587
Accrued employee bonus compensation	325	1,197
Employee withholdings	7	21
Other accrued expenses	435	298
Total accrued expenses	$ 2,211	$ 2,103

Borrowings - Additional Informa

Borrowings - Additional Information (Details)	Mar. 07, 2019USD ($)d$ / shares	Sep. 30, 2016USD ($)	Apr. 30, 2019USD ($)shares	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Payment of debt issuance costs				$ 1,143,000	$ 0
Loss on debt extinguishment				(814,000)	$ 0
Convertible debt and derivative liability				18,296,000		$ 0
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				(800,000)
Reacquisition price of outstanding debt				15,900,000
Carrying value of debt obligation				15,100,000
Senior convertible notes				8,500,000
Unamortized debt issuance cost				600,000
Bifurcated embedded conversion option derivative liability				9,800,000
Debt issuance costs				600,000
Loss on fair value adjustment of derivative liability				2,900,000
Amortization of debt issuance costs				100,000
Fair value of convertible debt and derivative liability				$ 19,100,000
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%
Senior Convertible Note Purchase Agreement | Subsequent Event
Debt Instrument [Line Items]
Conversion of convertible note, amount			$ 2,000,000
Conversion of convertible note exchanged for shares | shares			1,626,000
Senior Convertible Note Purchase Agreement | ASC 815
Debt Instrument [Line Items]
Derivative, fair value				$ 7,000,000
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 ($)ft²	Mar. 31, 2019USD ($)Agreement	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)
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	$ 164,000
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 must furnish a security deposit in the form of a standby letter of credit in the amount of $0.3 million, which will be reduced by fifty-five thousand dollars every two years for ten years after the commencement of the lease
Security deposit in the form of a standby letter of credit	$ 300,000
Decrease in security deposit	$ 55,000
Operating lease right-of-use asset		3,317,000	$ 3,365,000	$ 0
Operating lease liability		$ 3,322,000	$ 3,368,000
Number of additional license agreements | Agreement		2
License agreements fee		$ 2,300,000
Maximum
Commitment And Contingencies [Line Items]
Milestone payments from the Company		19,000,000
Jersey City, New Jersey
Commitment And Contingencies [Line Items]
Rent expense		$ 100,000

Commitments and Contingencies_2

Commitments and Contingencies - Summary of Quantitative Information Associated with Amounts Recognized in Financial Statements for Lease (Detail) - USD ($) $ in Thousands	Mar. 01, 2018	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Operating lease cost		$ 166
Variable lease cost		9
Total operating lease expense		175
Total lease payments	$ 7,300	$ 164
Remaining Lease term (years)		10 years 3 months
Discount rate		15.00%

Commitments and Contingencies_3

Commitments and Contingencies - Future Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
2019		$ 498
2020		508
2021		518
2022		529
2023		716
Thereafter		4,203
Total		$ 6,972
2019	$ 334
2020	508
2021	518
2022	529
2023	716
Thereafter	4,203
Total	$ 6,808

Commitments and Contingencies_4

Commitments and Contingencies - Presentation of Operating Lease Liability and Right-of-Use Asset (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Present value of future minimum lease payments	$ 3,322	$ 3,368
Operating lease liability, current portion	27	23	$ 0
Operating lease liability, long-term portion	3,295	3,345	0
Total operating lease liability	3,322	3,368
Difference between future minimum lease payments and discounted cash flows	3,486	3,604
Operating lease right-of-use asset	$ 3,317	$ 3,365	$ 0

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2016	Apr. 30, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	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)			125,000,000		125,000,000
Common stock, shares issued (in shares)			50,232,429		47,971,989
Common stock, shares outstanding (in shares)			50,232,429		47,971,989
Warrant liabilities fair value adjustment			$ 6,522	$ (3,554)
Warrant liabilities			$ 7,500
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 | Subsequent Event
Schedule Of Capitalization Equity [Line Items]
Conversion of convertible note, amount		$ 2,000
Conversion of convertible note exchanged for shares		1,626,000

Stockholder's Equity - Summary

Stockholder's Equity - Summary of Common Stock Shares Activity (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning balance	$ 31,225	$ 21,410
Beginning balance (in shares)	47,971,989
Net loss	$ (22,908)	(4,002)
Stock-based compensation expense	492	425
Common stock issued through employee stock purchase plan	20	20
Common stock issued, net of expenses	2,509	18,998
Common stock issued for vested restricted stock units	(8)	(7)
Ending balance	$ 11,330	36,844
Ending balance (in shares)	50,232,429
Common Stock
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning balance	$ 48	$ 29
Beginning balance (in shares)	47,971,989	28,971,651
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)	19,259	13,591
Common stock issued, net of expenses	$ 2	$ 18
Common stock issued, net of expenses (in shares)	2,226,569	17,852,193
Common stock issued for vested restricted stock units	$ 0	$ 0
Common stock issued for vested restricted stock units (in shares)	14,612	6,006
Ending balance	$ 50	$ 47
Ending balance (in shares)	50,232,429	46,843,441
Additional Paid-in Capital
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning balance	$ 248,895	$ 226,631
Net loss	0	0
Stock-based compensation expense	492	425
Common stock issued through employee stock purchase plan	20	20
Common stock issued, net of expenses	2,507	18,980
Common stock issued for vested restricted stock units	(8)	(7)
Ending balance	251,906	246,049
Accumulated Deficit
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning balance	(217,718)	(205,250)
Net loss	(22,908)	(4,002)
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	$ (240,626)	$ (209,252)

Stockholder's Equity - Schedule

Stockholder's Equity - Schedule of Reserved Shares of Common Stock for Future Issuance (Detail) - shares	Mar. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Common shares reserved for future issuance	32,121,323	30,404,957
6.0% Convertible Senior Notes due 2025
Class of Stock [Line Items]
Common shares reserved for future issuance	13,008,000	0
2014 Equity Incentive Plan
Class of Stock [Line Items]
Common shares reserved for future issuance	372,312	612,018
2014 Employee Stock Purchase Plan
Class of Stock [Line Items]
Common shares reserved for future issuance	91,819	81,667
2015 Inducement Plan
Class of Stock [Line Items]
Common shares reserved for future issuance	5,000	5,000
Series C1 Preferred Warrants
Class of Stock [Line Items]
Common shares reserved for future issuance	14,033	14,033
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 1 Warrant
Class of Stock [Line Items]
Common shares reserved for future issuance	0	13,198,075
March 2018 Public Offering | Series 2 Warrant
Class of Stock [Line Items]
Common shares reserved for future issuance	7,988,175	7,988,175
Warrants to purchase common stock associated with 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	5,310,498	4,052,913
Restricted Stock Units
Class of Stock [Line Items]
Common shares reserved for future issuance	990,301	111,891

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, 2019	Dec. 31, 2018
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	1,918,879	1,158,866
Possible future issuance under equity compensation plan (in shares)	372,312

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, 2019	Dec. 31, 2018
Number of Shares
Beginning balance - Outstanding (shares)	4,052,913
Granted (shares)	1,270,500
Exercised (shares)	0
Forfeited/Cancelled(shares)	(12,915)
Ending balance - Outstanding (shares)	5,310,498	4,052,913
Exercisable (shares)	2,621,464
Vested or expected to vest (shares)	5,310,498
Weighted- Average Exercise Price
Beginning balance - Outstanding (in dollars per share)	$ 4.37
Granted (in dollars per share)	1.26
Exercised (in dollars per share)	0
Forfeited/Cancelled (in dollars per share)	9.35
Ending balance - Outstanding (in dollars per share)	3.62	$ 4.37
Exercisable (in dollars per share)	5.43
Vested or expected to vest (in dollars per share)	$ 3.62
Weighted- Average Remaining Contractual Life (in years)
Balance - Outstanding	7 years 8 months 8 days	7 years 2 months 23 days
Exercisable	6 years 3 months 14 days
Vested or expected to vest	7 years 8 months 8 days
Aggregate Intrinsic Value ($000)
Balance - Outstanding	$ 333	$ 0
Exercisable	13
Vested and expected to vest	$ 333

Stock-based Compensation - Sche

Stock-based Compensation - Schedule of Restricted Stock Units ("RSU") Activity (Details) - Restricted Stock Units (RSUs)	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Number of Shares
Beginning balance - Outstanding (shares) | shares	111,891
Options granted in period (shares) | shares	901,000
Vested (shares) | shares	(22,590)
Forfeited/Cancelled (shares) | shares	0
Ending balance - Outstanding (shares) | shares	990,301
Weighted Average Grant Date Fair Value Per Share
Beginning balance - Outstanding (in dollars per share) | $ / shares	$ 2.06
Granted (in dollars per share) | $ / shares	1.38
Vested (in dollars per share) | $ / shares	2.30
Forfeited/Cancelled dollars per share) | $ / shares	0
Ending balance - Outstanding (in dollars per share) | $ / shares	$ 1.43
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, 2019	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-based compensation expense	$ 492,000	$ 425,000
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, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense related to stock options	$ 492	$ 425
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense related to stock options	158	108
Selling, general and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense related to stock options	$ 334	$ 317

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, 2019	Dec. 31, 2018
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	$ 13,278	$ 11,767
Fair value of financial liabilities	17,348	986
Warrant liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	7,508	986
Derivative liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	9,840
Cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets		213
Restricted cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	328	328
Money market funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets	12,950	11,226
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	13,278	11,767
Fair value of financial liabilities	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Warrant liabilities
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
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		213
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	328	328
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	12,950	11,226
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 liabilities
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
Significant Other Observable Inputs (Level 2) | Cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets		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	17,348	986
Significant Unobservable Inputs (Level 3) | Warrant liabilities
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	7,508	986
Significant Unobservable Inputs (Level 3) | Derivative liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial liabilities	9,840
Significant Unobservable Inputs (Level 3) | Cash
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Fair value of financial assets		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 - 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, 2019USD ($)
Warrant liabilities
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 986
Loss adjustment to fair value	6,522
Ending balance	7,508
Derivative liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	0
Bifurcated embedded conversion option associated with Notes	6,960
Loss adjustment to fair value	2,880
Ending balance	$ 9,840