Zosano Pharma (ZSANQ) 10-Q 14 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 10, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	ZSAN
Entity Registrant Name	Zosano Pharma Corp
Entity Central Index Key	0001587221
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		17,723,039

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 6,142	$ 9,140
Marketable securities at fair value	4,896	13,862
Prepaid expenses and other current assets	921	358
Total current assets	11,959	23,360
Restricted cash	455	455
Property and equipment, net	16,869	11,916
Operating lease right-of-use assets	6,219
Other long-term assets	21	49
Total assets	35,523	35,780
Current liabilities:
Accounts payable	3,678	4,450
Accrued compensation	2,742	2,092
Build-to-suit obligation, current portion	2,451	2,326
Operating lease liabilities, current portion	985
Other accrued liabilities	5,304	2,419
Total current liabilities	15,160	11,287
Build-to-suit obligation, long-term portion, net of debt issuance costs and discount	4,044	4,478
Operating lease liabilities, long-term portion	6,638
Other liabilities	30	18
Deferred rent	0	1,287
Total liabilities	25,872	17,070
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value, 5,000,000 shares authorized; none issued and outstanding as of March 31, 2019 and December 31, 2018	0	0
Common stock, $0.0001 par value; 250,000,000 shares authorized; 11,973,039 shares issued and outstanding as of March 31, 2019 and December 31, 2018	1	1
Additional paid-in capital	280,307	279,946
Accumulated deficit	(270,658)	(261,232)
Accumulated other comprehensive income (loss)	1	(5)
Total stockholders’ equity	9,651	18,710
Total liabilities and stockholders’ equity	$ 35,523	$ 35,780

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (usd per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	11,973,039	11,973,039
Common stock, shares outstanding	11,973,039	11,973,039

Condensed Statements of Operati

Condensed Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenue	$ 0	$ 0
Operating expenses:
Research and development	6,616	5,806
General and administrative	2,871	2,260
Total operating expenses	9,487	8,066
Loss from operations	(9,487)	(8,066)
Other income (expense):
Interest income	80	15
Interest expense	(41)	(156)
Other income, net	22	1
Loss before provision for income taxes	(9,426)	(8,206)
Provision for income taxes	0	0
Net loss	(9,426)	(8,206)
Unrealized gain on marketable securities, net of tax	6	0
Comprehensive loss	$ (9,420)	$ (8,206)
Net loss per common share – basic and diluted (in USD per share)	$ (0.79)	$ (4.16)
Weighted-average shares used in computing net loss per common share – basic and diluted (in shares)	11,973,039	1,973,039

Condensed Statement of Changes

Condensed Statement of Changes in Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2017		1,973,039
Beginning balance at Dec. 31, 2017	$ 7,048	$ 0	$ 232,922	$ (225,874)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	139		139
Unrealized gain on marketable securities	0
Net loss	(8,206)			(8,206)
Beginning balance (in shares) at Mar. 31, 2018		1,973,039
Beginning balance at Mar. 31, 2018	$ (1,019)	$ 0	233,061	(234,080)	0
Beginning balance (in shares) at Dec. 31, 2018	11,973,039	11,973,039
Beginning balance at Dec. 31, 2018	$ 18,710	$ 1	279,946	(261,232)	(5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	361		361
Unrealized gain on marketable securities	6				6
Net loss	$ (9,426)			(9,426)
Beginning balance (in shares) at Mar. 31, 2019	11,973,039	11,973,039
Beginning balance at Mar. 31, 2019	$ 9,651	$ 1	$ 280,307	$ (270,658)	$ 1

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net loss	$ (9,426)	$ (8,206)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	361	139
Amortization of operating lease right-of-use assets	196
Depreciation	164	194
Effective interest on financing obligations	28	41
Accretion of interest on debt securities	(27)	0
Deferred rent	0	314
Change in operating assets and liabilities:
Prepaid expenses and other assets	(180)	(362)
Accounts payable	654	909
Accrued compensation and other accrued liabilities	983	835
Operating lease liabilities	(222)
Net cash used in operating activities	(7,469)	(6,136)
Cash flows from investing activities:
Proceeds from maturities of marketable securities	9,000	0
Purchases of property and equipment	(4,016)	(451)
Net cash provided by (used in) investing activities	4,984	(451)
Cash flows used in financing activities:
Principal payments made on financing obligations	(513)	(1,527)
Net decrease in cash, cash equivalents and restricted cash	(2,998)	(8,114)
Cash, cash equivalents and restricted cash at beginning of period	9,595	12,106
Cash, cash equivalents and restricted cash at end of period	6,597	3,992
Supplemental cash flow information:
Cash paid for interest	185	116
Non-cash investing and financing activities:
Acquisition of property and equipment under accounts payable and other accrued liabilities	4,252	340
Right-of-use assets acquired under finance lease obligations	22
Accrued offering costs	$ 382	$ 561

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation The Company Zosano Pharma Corporation (the “Company”) is a clinical stage biopharmaceutical company focused on providing rapid systemic administration of therapeutics to patients using its proprietary Adhesive Dermally-Applied Microarray, or ADAM™, technology. Basis of Presentation The condensed financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) for interim financial information, the instructions to Form 10-Q and Regulation S-X. They do not include all the information and notes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 , or any other subsequent period. These financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2018 , included in the Company’s annual report on Form 10-K and filed with the United States Securities and Exchange Commission (“SEC”) on March 25, 2019. Certain prior year amounts have been reclassified for consistency with the current year presentation. These reclassifications had no effect on the reported results of operations. Use of Estimates The preparation of the accompanying condensed financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the condensed financial statements, and the reported amounts of revenue and expenses during the periods reported. Actual results could differ from those estimates. Liquidity and Substantial Doubt in Going Concern Since inception, the Company has incurred recurring operating losses and negative cash flows from operating activities, and as of March 31, 2019 , had an accumulated deficit of $270.7 million . As of March 31, 2019 , the Company had approximately $11.0 million in cash, cash equivalents and marketable securities. Presently, the Company does not have sufficient cash, cash equivalents and marketable securities to enable it to fund the anticipated level of operations and meet its obligations as they become due within twelve months following the date of issuance of this Quarterly Report on Form 10-Q. The aforementioned factors raise substantial doubt about the Company’s ability to continue as a going concern for a period of one year from the issuance of these financial statements. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. On April 11, 2019, the Company closed a public offering of 5,000,000 shares of common stock at a price to the underwriter of $3.29 per share. On May 8, 2019, the underwriter purchased 750,000 shares at a price to the underwriter of $3.29 per share pursuant to the exercise of the underwriter's option to purchase additional shares. The aggregate net proceeds were approximately $18.4 million , after deducting underwriting costs and estimated offering expenses (See Note 10. Subsequent Event ). The Company plans to raise additional funding through financing, a capital offering, a license or collaboration agreement or a combination of such sources of capital. However, there are no assurances that additional funding will be achieved and that the Company will succeed in its future operations. The Company’s inability to obtain required funding in the near future or its inability to obtain funding on favorable terms will have a material adverse effect on its operations and strategic development plan for future growth. If the Company cannot successfully raise additional capital and implement its strategic development plan, its liquidity, financial condition and business prospects will be materially and adversely affected, and it may have to cease operations. The Company will continue to evaluate its timelines, strategic needs, and working capital requirements. There can be no assurance that if the Company attempts to raise additional capital, it will be successful in doing so on terms acceptable to the Company, or at all. Further, there can be no assurance that it will be able to gain access and/or be able to execute on securing new sources of funding, new development opportunities, successfully obtain regulatory approvals for and commercialize new products, achieve significant product revenues from its products (if approved), or achieve or sustain profitability in the future.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Significant Accounting Policies The Company’s significant accounting policies are included in “Part II - Item 8 - Financial Statements and Supplementary Data - Note 2 - Summary of Significant Accounting Policies” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 . As discussed in our Annual Report, the Company adopted the new leases standards in the first quarter of 2019 and otherwise, there have been no other significant changes to these accounting policies during the first three months of 2019. Leases ASC Topic 842, Leases , requires lessees to recognize right-of-use assets and lease liabilities for most leases on the balance sheet and to provide expanded disclosures about leasing arrangements. The Company adopted Topic 842 effective January 1, 2019 using the optional transition method and did not restate comparative periods. There was no effect on accumulated deficit at adoption. The Company has elected the package of practical expedients to (i) not reassess whether expired or existing contracts are or contain leases, (ii) not reassess the lease classification for any expired or existing leases and (iii) not reassess the accounting for initial direct costs. The adoption of the new leases standard resulted in the following adjustments to the consolidated balance sheet as of January 1, 2019: December 31, 2018 Adoption Impact January 1, 2019 (in thousands) (unaudited; in thousands) Operating lease right-of-use assets $ — $ 6,415 $ 6,415 Operating leases liabilities, current portion $ — $ 945 $ 945 Other accrued liabilities $ 2,414 $ (143 ) $ 2,271 Operating lease liabilities, long-term portion $ — $ 6,900 $ 6,900 Deferred rent $ 1,287 $ (1,287 ) $ — As of December 31, 2018 , the short-term portion of deferred rent was recorded in other accrued liabilities. The adoption impact was a non-cash operating activity for the period ended March 31, 2019. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes its incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received. Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments with an original maturity of 90 days or less to be cash equivalents. As of March 31, 2019 and December 31, 2018 , the Company had restricted cash of approximately $0.5 million consisting of deposits of $0.3 million to secure its building lease until the end of the lease term, a deposit of approximately $0.1 million to a utility provider and $35,000 to secure corporate purchasing cards. The following table provides a reconciliation of cash, cash equivalents and restricted cash to amounts shown in the statement of cash flows: March 31, 2019 March 31, 2018 (unaudited; in thousands) Cash and cash equivalents $ 6,142 $ 3,537 Restricted cash 455 455 Total $ 6,597 $ 3,992 Marketable Securities Marketable securities generally consist of debt securities with original maturities greater than 90 days and remaining maturities of less than one year. All of the Company's investments are classified as available-for-sale and carried at fair value based upon quoted market price. The change in unrealized gains and losses is reported as a separate component of other comprehensive income (loss) on the statements of operations and comprehensive loss and as a separate component of stockholders' equity on the balance sheets. Interest income includes interest, dividends, accretion and amortization of purchase premiums and discounts and realized gains and losses on sales of securities, if any. The cost of securities sold is based on the specific-identification method. The Company monitors its investment portfolio for potential impairment on a quarterly basis. If the carrying amount of an investment in marketable securities exceeds its fair value and the decline in value is determined to be other-than-temporary, the carrying amount of the security is reduced to fair value and a loss is recognized in operating results for the amount of such decline. In order to determine whether a decline in value is other-than-temporary, the Company evaluates, among other factors, the cause of the impairment, including the creditworthiness of the security issuers, the number of securities in an unrealized loss position, the severity and duration of the unrealized losses, and its intent and ability to hold the security to maturity or forecasted recovery. Investments with original maturities between three and twelve (12) months are considered short-term investments. Investments with original maturities greater than 12 months are considered long-term investments. Fair Value Instruments The Company records its financial assets and liabilities at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: • Level I: Inputs which include quoted prices in active markets for identical assets and liabilities. • Level II: Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level III: Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The carrying values of certain assets and liabilities of the Company, such as cash and cash equivalents and accounts payable approximate fair value due to their relatively short maturities. The carrying value of the Company’s short-term financial obligations approximates their fair value as the terms of the borrowing are consistent with current market rates and the duration to maturity is short. The carrying value of the Company's long-term financial obligations approximates fair value because interest rates approximate market rates that the Company could obtain for debt with similar terms and maturities. Net Loss Per Common Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per common share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, common stock warrants and stock options are considered to be potential dilutive securities but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented. The following outstanding common stock equivalents were excluded from the computations of diluted net loss per common share for the periods presented as the effect of including such securities would be antidilutive: March 31, 2019 March 31, 2018 (unaudited) Warrants to purchase common stock 274,524 199,524 Options to purchase common stock 1,456,126 124,379 Total 1,730,650 323,903 Recent Accounting Pronouncements In August 2018, the FASB issued ASU2018-15, Intangible - Goodwill and Other - Internal-Use Software (Subtopic 350-40) , which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. ASU2018-15 is effective for the Company in the first quarter of 2020. Early adoption is permitted. ASU2018-15 permits either a prospective or retrospective transition approach. The Company is currently evaluating ASU2018-15 to determine the impact to its financial statements and related disclosures. In August 2018, the FASB issued ASU2018-13, Fair Value Measurement (Topic 820) . The new guidance modifies the disclosure requirements on fair value measurements. ASU2018-13 is effective for the Company beginning in the first quarter of 2020 and must be adopted on a modified retrospective basis, with certain exceptions. Early adoption is permitted. The Company does not expect ASU2018-13 to have a significant impact to its financial statements and disclosures. In June 2016, the FASB issued ASU2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments and in November 2018, issued ASU2018-19, Codification Improvements to Topic 326, Financial Instruments - Credit Losses . This new guidance is intended to present credit losses on available for sale debt securities as an allowance rather than as a write-down. Entities are required to apply the standard's provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. ASU2016-13 and ASU2018-19 are effective for the Company in the first quarter of 2020. The Company is currently evaluating ASU2016-13 and ASU2018-19 to determine the impact to its financial statements and disclosures.

Cash Equivalents and Investment

Cash Equivalents and Investments in Marketable Securities	3 Months Ended
	Mar. 31, 2019
Cash and Cash Equivalents [Abstract]
Cash Equivalents and Investments in Marketable Securities	Cash Equivalents and Investments in Marketable Securities The following tables present summaries of the Company's cash equivalents and marketable securities measured at fair value on a recurring basis: Fair Value Measurements Total Quoted prices Significant Significant (unaudited; in thousands) As of March 31, 2019: Money market funds $ 4,905 $ 4,905 $ — $ — Corporate notes and bonds 1,500 — 1,500 — U.S. treasuries 3,396 3,396 — — Total $ 9,801 $ 8,301 $ 1,500 $ — Classified as: Cash equivalents $ 4,905 Marketable securities at fair value 4,896 Total $ 9,801 Fair Value Measurements Total Quoted prices in active market Level I Significant other observable inputs Level II Significant unobservable inputs Level III (in thousands) As of December 31, 2018: Money market funds $ 4,830 $ 4,830 $ — $ — Commercial paper 1,497 — 1,497 — Corporate notes and bonds 6,989 — 6,989 — U.S. treasuries 8,375 8,375 — — Total $ 21,691 $ 13,205 $ 8,486 $ — Classified as: Cash equivalents $ 7,829 Marketable securities at fair value 13,862 Total $ 21,691 The Company did not transfer any marketable securities measured at fair value on a recurring basis to or from Level I and Level II during the three month period ended March 31, 2019 . The following tables summarize the unrealized positions for available-for-sale fixed maturity debt securities disaggregated by class of instrument: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (unaudited; in thousands) As of March 31, 2019: Money market funds $ 4,905 $ — $ — $ 4,905 Corporate notes and bonds 1,500 — — 1,500 U.S. treasuries 3,395 1 — 3,396 Total $ 9,800 $ 1 $ — $ 9,801 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) As of December 31, 2018: Money market funds $ 4,830 $ — $ — $ 4,830 Commercial paper 1,497 — — 1,497 Corporate notes and bonds 6,994 — (5 ) 6,989 U.S. treasuries 8,375 — — 8,375 Total $ 21,696 $ — $ (5 ) $ 21,691

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	Balance Sheet Components The following table summarizes the Company's prepaid expenses and other current assets for each of the periods presented: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Offering costs $ 517 $ 114 Prepaid insurance 241 45 Other 163 199 Total $ 921 $ 358 The following table summarizes the Company’s other accrued liabilities for each of the periods presented: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Construction-in-progress obligations $ 2,969 $ 395 Pre-clinical and clinical study 971 483 Professional service fees 301 112 Contract manufacturing 407 834 Accrued taxes 50 187 Other 606 408 Total $ 5,304 $ 2,419 The following table summarizes the Company’s property and equipment for each of the periods presented: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Leasehold improvements $ 16,951 $ 16,690 Manufacturing equipment 11,833 10,387 Laboratory and office equipment 1,479 1,434 Computer equipment and software 235 206 Construction-in-progress 12,895 9,558 43,393 38,275 Less: accumulated depreciation (26,524 ) (26,359 ) Total $ 16,869 $ 11,916 Depreciation expense was approximately $0.2 million and $0.2 million for the three months ended March 31, 2019 and 2018 , respectively. The gross property and equipment and accumulated depreciation presented in the above table includes right-of-use assets acquired under finance leases and the related accumulated amortization, respectively. Right-of-use assets under finance leases were comprised of office and computer equipment of approximately $43,000 and $24,000 at March 31, 2019 and December 31, 2018 , respectively. Accumulated amortization related to right-of-use assets under finance leases was approximately $15,000 at March 31, 2019 . As of March 31, 2019 , construction-in-progress included $9.7 million of an asset relating to the build-to-suit arrangement for construction of the Company's commercial coating and primary packaging system, of which capitalized construction period interest was $0.7 million (See Note 6. Debt Financing ).

Leases

Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases, Finance	Leases Operating Leases The Company has a non-cancelable operating lease with BMR-34790 Ardentech Court LP for office, research and development, and manufacturing facilities in Fremont, California through August 31, 2024, with an option to further extend the lease for an additional 60 months subject to certain terms and conditions. The lease agreement calls for monthly base rent of approximately $136,000 for the period commencing September 1, 2017, with annual increases on September 1 of each subsequent year until the lease year beginning September 1, 2023. The agreement also provided for rent abatements, subject to certain conditions, totaling $0.3 million and certain tenant improvements to be completed at the landlord’s expense of approximately $1.0 million . The Company entered into a three year, noncancelable lease for telephone equipment in January 2018. Per the terms of the agreements, the Company does not have any residual value guarantees. In calculating the present value of the lease payments, the Company has elected to utilize its incremental borrowing rate. The Company has elected to account for each lease component and its associated non-lease components as separate lease components. The building lease includes non-lease components (i.e. common area maintenance) which are charged and paid separately from rent based on actual costs incurred and therefore are not included in the right-of-use asset and lease liability but reflected in operating expense in the period incurred. Finance Leases The Company leases certain equipment under non-cancelable agreements which expire between 2021 and 2022 that were accounted for as capital leases under ASC840. The leases were not reassessed at adoption of ASC842 as the Company elected the practical expedient to not reassess existing leases. The finance lease obligations were as follows: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Finance lease obligations, current portion $ 13 $ 5 Finance lease obligations, long-term portion $ 30 $ 18 The components of lease cost were as follows: Description of lease costs Three months ended March 31, 2019 (unaudited; in thousands) Finance Lease Cost Amortization of finance lease right-of-use assets $ 15 Interest on finance lease obligations 9 Operating lease costs 410 Total $ 434 Cash payments for leases were as follows: Description of cash payment Three months ended March 31, 2019 (unaudited; in thousands) Operating cash flows from operating leases $ 436 Operating cash flows from finance leases $ 3 Financing cash flows from finance leases $ 3 Lease term and discount rate were as follows: March 31, 2019 Description of other lease information Operating leases Finance leases (unaudited) Weighted-average remaining lease term 5.49 2.51 Weighted average discount rate 11 % 27 % As of March 31, 2019 , annual scheduled lease payments were as follows: Year Operating leases Finance leases (unaudited; in thousands) Remainder of 2019 $ 1,326 $ 18 2020 1,815 24 2021 1,863 14 2022 1,914 3 2023 1,970 — 2024 1,340 — Total undiscounted cash flows 10,228 59 Less: amount representing interest (2,605 ) (16 ) Present value of leased liabilities $ 7,623 $ 43
Leases, Operating	Leases Operating Leases The Company has a non-cancelable operating lease with BMR-34790 Ardentech Court LP for office, research and development, and manufacturing facilities in Fremont, California through August 31, 2024, with an option to further extend the lease for an additional 60 months subject to certain terms and conditions. The lease agreement calls for monthly base rent of approximately $136,000 for the period commencing September 1, 2017, with annual increases on September 1 of each subsequent year until the lease year beginning September 1, 2023. The agreement also provided for rent abatements, subject to certain conditions, totaling $0.3 million and certain tenant improvements to be completed at the landlord’s expense of approximately $1.0 million . The Company entered into a three year, noncancelable lease for telephone equipment in January 2018. Per the terms of the agreements, the Company does not have any residual value guarantees. In calculating the present value of the lease payments, the Company has elected to utilize its incremental borrowing rate. The Company has elected to account for each lease component and its associated non-lease components as separate lease components. The building lease includes non-lease components (i.e. common area maintenance) which are charged and paid separately from rent based on actual costs incurred and therefore are not included in the right-of-use asset and lease liability but reflected in operating expense in the period incurred. Finance Leases The Company leases certain equipment under non-cancelable agreements which expire between 2021 and 2022 that were accounted for as capital leases under ASC840. The leases were not reassessed at adoption of ASC842 as the Company elected the practical expedient to not reassess existing leases. The finance lease obligations were as follows: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Finance lease obligations, current portion $ 13 $ 5 Finance lease obligations, long-term portion $ 30 $ 18 The components of lease cost were as follows: Description of lease costs Three months ended March 31, 2019 (unaudited; in thousands) Finance Lease Cost Amortization of finance lease right-of-use assets $ 15 Interest on finance lease obligations 9 Operating lease costs 410 Total $ 434 Cash payments for leases were as follows: Description of cash payment Three months ended March 31, 2019 (unaudited; in thousands) Operating cash flows from operating leases $ 436 Operating cash flows from finance leases $ 3 Financing cash flows from finance leases $ 3 Lease term and discount rate were as follows: March 31, 2019 Description of other lease information Operating leases Finance leases (unaudited) Weighted-average remaining lease term 5.49 2.51 Weighted average discount rate 11 % 27 % As of March 31, 2019 , annual scheduled lease payments were as follows: Year Operating leases Finance leases (unaudited; in thousands) Remainder of 2019 $ 1,326 $ 18 2020 1,815 24 2021 1,863 14 2022 1,914 3 2023 1,970 — 2024 1,340 — Total undiscounted cash flows 10,228 59 Less: amount representing interest (2,605 ) (16 ) Present value of leased liabilities $ 7,623 $ 43

Debt Financing

Debt Financing	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Debt Financing	Debt Financing Build-to-Suit Obligation with Trinity In September 2018, the Company entered into a build-to-suit arrangement with Trinity Capital Fund III, L.P., ("Trinity") in order to obtain financing for the third party construction of the Company's commercial coating and primary packaging system (the "Equipment"), expected to be completed in the second quarter of 2020. Under the agreement, Trinity will make available to the Company $14.0 million for equipment costs and associated soft costs ("Total Cost"), with an initial drawdown of $5.0 million and additional drawdowns in increments of not less than $0.5 million , until March 30, 2020. At March 30, 2020, any unused portion of the $14.0 million will be subject to a non-utilization fee equal to 3% of the unused amount. In consideration of the financing arrangement, as collateral, the Company granted Trinity a first-priority lien and security interest in substantially all the Company's assets. The Company determined that it is the deemed owner, for financial reporting purposes, of the Equipment during the construction period due to its involvement in and its obligations related to the construction of the Equipment. Accordingly, construction costs incurred were recorded as construction-in-progress, a component of property and equipment on the balance sheet and the Trinity financing obligation was recorded as a build-to-suit obligation on the balance sheet. Under the financing arrangement, each individual drawdown represents a separate financing arrangement with its own 36 -month-term and stated interest rate. Each drawdown is non-cancelable, with no prepayment options. Each drawdown has embedded optional purchase options to (i) extend the term for an additional three months , with the option to purchase the equipment at 4% of the Total Cost, which is equal to the drawdown amount, following the end of such extended term, or (ii) purchase the equipment at 12% of the Total Cost, which is equal to the drawdown amount, at the end of the 36-month-term. The Company intends to exercise the optional purchase option of 12% at the end of each 36 -month-term ("Purchase Option Fee"). The transfer of title from Trinity to the Company will occur at the end of the final 36 -month-term, provided that the purchase option was executed, and the Purchase Option Fee was paid in full at the end of each 36 - month-term . Failure to pay any of the Purchase Option Fees will result in Trinity retaining title to the Equipment and the Company paying a 6% restocking fee. In September 2018, upon commencement of this arrangement, the Company drew its first drawdown of $5.0 million , of which $2.7 million was for the Company’s commercial coating and primary packaging system, $2.0 million was used to extinguish an existing loan (see below), and the remaining $0.3 million was withheld by Trinity for interim interest and a security deposit that will be applied to the final monthly payment. The monthly loan payment is $160,000 , with a stated and effective interest rate of 9.43% and 26.28% , respectively. The Purchase Option Fee was recorded as a discount to the principal balance. The first drawdown of $5.0 million matures on October 1, 2021 . In connection with the build-to-suit arrangement, the Company issued common stock warrants (“Trinity Warrants”) for a total of 75,000 shares of common stock at an exercise price of $3.59 per share. The Trinity Warrants will expire on September 25, 2025 . Proceeds allocated to the Trinity Warrants based on their relative fair value approximated $243,000 and were recorded as a discount to the initial $5.0 million drawdown under the Trinity financing arrangement and are being amortized as interest over the term of the September 2018 drawdown. In December 2018, the Company drew a second drawdown of $2.8 million , of which $2.6 million was for the Company’s commercial coating and primary packaging system, and the remaining $0.2 million was withheld by Trinity for interim interest, the first monthly payment and a security deposit that will be applied to the final monthly payment. The monthly loan payment is approximately $90,000 with a stated and effective interest rate of 9.68% and 19.58% , respectively. The Purchase Option Fee was recorded as a discount to the principal balance. The second drawdown of $2.8 million matures on January 1, 2022 . As of March 31, 2019 , the Company had an aggregate commercial coating and primary packaging system construction-in-progress ("CIP") balance of $9.7 million that included $0.7 million of interest related to its build-to-suit obligation, of which $71,000 was attributable to the Trinity Warrants; and a net build-to-suit obligation of $6.5 million . As of March 31, 2019 , $6.2 million remains available to the Company under the Trinity build-to-suit arrangement. The following table is a summary of the Company's build-to-suit obligation as of March 31, 2019 (unaudited; in thousands) : Build-to-suit obligation principal amount $ 6,609 Build-to-suit obligation Purchase Option Fees 760 Less: unamortized Purchase Option Fees (534 ) unamortized fair value of free-standing warrants (173 ) unamortized debt discount (149 ) unamortized debt issuance costs (18 ) Build-to-suit obligation, net of debt issuance costs and discount $ 6,495 Build-to-suit obligation, current portion $ 2,451 Build-to-suit obligation, long-term portion, net of debt issuance costs and discount 4,044 Build-to-suit obligation, net of debt issuance costs and discount $ 6,495 For the three months ended March 31, 2019 , the Company capitalized $0.4 million of interest as CIP, a component of property and equipment on the Company's balance sheet. Future minimum payments on the Company’s build-to-suit obligation, including payment of principal and interest and Purchase Option Fees for each year ending December 31 were as follows: Year Principal Interest Purchase Option Fees (unaudited; in thousands) Remainder of 2019 $ 1,815 $ 433 $ — 2020 2,632 367 — 2021 2,162 107 936 Total $ 6,609 $ 907 $ 936 Senior Secured Term Loan with Hercules In June 2014 and June 2015, the Company entered into a loan and security agreement and the first amendment to the loan and security agreement, respectively, with Hercules Capital Inc. (“Hercules”). Hercules provided the Company a $15.0 million loan (“Hercules Term Loan”) of which equal installment payments of principal and interest were due monthly, with a scheduled maturity date of December 1, 2018 . The Hercules Term Loan bore interest at a variable rate equal to the greater of (i) 7.95% , or (ii) 7.95% plus the prime rate as quoted in the Wall Street Journal minus 5.25% . On September 25, 2018, the Company paid all its outstanding obligations under the Hercules Term Loan, including an end of term charge of $0.4 million . For the three months ended March 31, 2018 , the Company recorded total interest expense of $0.2 million related to the Hercules Term Loan.

Warrants

Warrants	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
Warrants	Warrants The following table summarizes the warrants issued and outstanding as of March 31, 2019 : Warrants Warrants Issued Warrants Exercised Warrants Expired Warrants Exercise Price Expiration Date (unaudited) PIPE Financing - Series B 195,906 — — — 195,906 $ 31.00 8/19/2021 Hercules - June 2014 1,583 — — — 1,583 $ 176.80 1/27/2020 Hercules - June 2015 2,035 — — — 2,035 $ 147.40 6/23/2020 Trinity - September 2018 75,000 — — — 75,000 $ 3.59 9/25/2025 Total 274,524 — — — 274,524

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Employment Arrangements The Company has entered into employment agreements with its executive officers. Generally, the terms of these agreements provide for base salary, health care coverage, annual bonus and stock options. In addition, if the Company terminates the officer other than for cause, death, or disability, or if the officer terminates his or her employment with the Company for good cause, the officer shall be entitled to receive certain severance compensation and benefits as described in each such agreement as well as automatic acceleration of vesting, at a certain percentage ( 25% or 100% ), of their unvested stock options and other equity awards on the date of such termination. Equipment Purchase Commitments In May 2018 and February 2019, the Company entered into a $12.2 million purchase order and a $1.3 million revision to the purchase order with an equipment manufacturer to purchase a commercial coating and primary packaging system for the production of its product candidate, Qtrypta™ (M207), for an aggregate purchase price of $13.5 million . The terms of the purchase commitment are contingent upon performance of certain milestones. The Company anticipates that the obligation will be paid over an 18 -month period. As of March 31, 2019 , the Company had made payments totaling $5.9 million . The Company also entered into agreements with equipment manufacturers to produce its patch assembly machine and its applicator and retainer machinery. The aggregate purchase price of this equipment is $3.6 million of which $1.6 million was paid as of March 31, 2019 . Contract Manufacturing Organizations In September 2018, the Company entered into a manufacturing and supply agreement with a contract manufacturing organization ("CMO") to provide services related to the manufacture and commercialization of Qtrypta™ (M207). During the term of the agreement, the CMO will provide services related to processing, packaging, labeling and storing Qtrypta™ (M207), in addition to other services such as stability testing, quality control and assurance, and waste disposal. The agreement calls for annual fees of $1.0 million in 2019 escalating to $14.0 million in 2024 , to be paid in equal monthly installments. Beginning in 2020, the annual fee includes the production of a defined number of units with an option to purchase additional units at a defined price. The agreement contains negotiated representations and warranties, indemnification, limitations of liability, and other provisions. The initial term of the agreement continues until the seventh anniversary of the date on which the Company receives New Drug Application approval of Qtrypta™ (M207) in the United States. The Company may elect to terminate the agreement at any time prior to certain regulatory approvals or if such regulatory approval is withdrawn under certain circumstances. Upon termination of the contract, the Company would incur cancellation fees of 50% of the annual fee due in the year that the contract is terminated, estimated to be between $1.0 million and $1.4 million , and costs to remove the Company's equipment and restore the CMO's facility to its original condition. The Company or the CMO may terminate the agreement for the other’s uncured material breach, uncured force majeure or bankruptcy or insolvency-related events. As of March 31, 2019 , the Company had entered into agreements with CMOs for the construction of manufacturing space and technology transfer fees of $4.1 million of which $0.6 million had been paid. Indemnification and Guarantees In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future but have not yet been made. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may record charges in the future as a result of these indemnification obligations. The Company also has indemnification obligations to its officers and directors for specified events or occurrences, subject to some limits, while they are serving at the Company’s request in such capacities. There have been no claims to date and the Company has director and officer insurance that may enable the Company to recover a portion of any amounts paid for future potential claims. The Company believes the fair value of these indemnification agreements is minimal. Accordingly, the Company has not recorded any liabilities for these agreements as of March 31, 2019 . Legal Proceedings The Company is not party to any material pending legal proceedings. However, it may from time to time become involved in litigation relating to claims arising in the ordinary course of business.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Amended and Restated 2014 Equity and Incentive Plan The Amended and Restated 2014 Equity and Incentive Plan (“2014 Plan”) provides for the issuance of (i) cash awards and (ii) equity-based awards, denominated in shares of the Company’s common stock, including incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units, unrestricted stock awards, performance share awards and dividend equivalent rights. Incentive stock options may be granted only to Company employees. Nonqualified stock options may be granted to Company employees, outside directors and consultants. As of March 31, 2019 , the Company had reserved 1,767,229 shares of its common stock for issuance under its 2014 Plan, subject to automatic annual increases as set forth in the 2014 Plan. Options and awards under the 2014 Plan may be granted for periods of up to ten years . Employee options granted by the Company generally vest over four years . Restricted stock awards granted to employees, directors and consultants can be subject to the same vesting conditions and the right of repurchase by the Company of unvested shares as determined by its board of directors. As of March 31, 2019 , the Company had 327,848 shares available for grant under the 2014 Plan. During the three month period ended March 31, 2019 , the Company granted stock options to purchase 32,500 shares of common stock to non-employee directors. The following table summarizes option and award activity, excluding inducement grants, for the three months ended March 31, 2019 (unaudited) : Shares Available for Grant Number of Shares Subject to Outstanding Options Weighted- Average Exercise Price per Share Weighted- Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value Balance at January 1, 2019 55,799 1,296,157 $ 5.75 9.23 $ — Additional shares reserved 419,056 — $ — Options granted (179,250 ) 179,250 $ 4.13 Options canceled/forfeited/expired 32,243 (32,243 ) $ 5.28 Balance at March 31, 2019 327,848 1,443,164 $ 5.56 9.05 $ 775,606 Exercisable at March 31, 2019 298,777 $ 9.26 8.47 $ 123,891 Vested or expected to vest at March 31, 2019 1,340,746 $ 5.64 9.04 $ 722,306 The aggregate intrinsic value is calculated as the difference between the exercise price of the option and the estimated fair value of the Company’s common stock for in-the-money options at March 31, 2019 . Inducement Grants The Company has also awarded inducement grants to purchase common stock to new employees outside the existing equity compensation plans in accordance with Nasdaq listing rule 5635(c)(4). Such options vest at a rate of 25% of the shares on the first anniversary of the commencement of such employee’s employment with the Company, and then one forty-eighth (1/48) of the shares monthly thereafter subject to such employee’s continued service. The following table summarizes the Company’s inducement grant stock option activity (unaudited) : Number of Shares Subject to Outstanding Options Weighted- Average Exercise Price per Share Weighted-Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value Balance at January 1, 2019 13,837 $ 20.60 4.52 $ — Options granted — $ — Options canceled/forfeited/expired (875 ) $ 22.80 Balance at March 31, 2019 12,962 $ 20.45 3.51 $ — Exercisable at March 31, 2019 10,357 $ 18.75 2.33 $ — Vested or expected to vest at March 31, 2019 12,788 $ 20.36 3.45 $ — Stock-Based Compensation Expense Total stock-based compensation expense recognized was as follows: Three months ended March 31, 2019 2018 (unaudited; in thousands) Research and development $ 165 $ 67 General and administrative 196 72 Total $ 361 $ 139 As of March 31, 2019 , the Company had $3.7 million of total unrecognized stock-based compensation, net of estimated forfeitures, related to outstanding stock options that will be recognized over a weighted-average period of 3.14 years. The Company’s stock-based compensation expense for stock options is estimated at the grant date based on the award’s fair value as calculated by the Black-Scholes option pricing model and is recognized as expense over the requisite service period. The Black-Scholes option pricing model requires various highly judgmental assumptions including expected volatility and expected term. As the Company does not have sufficient historical stock price information to meet the expected life of the stock-based awards, the Company uses a blended volatility that includes the Company's common stock trading history and supplements the remaining historical information with the trading history from the common stock of a set of comparable publicly traded biopharmaceutical companies. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of the Company's stock price becomes available. To estimate the expected term, the Company has opted to use the simplified method which is the use of the midpoint of the vesting term and the contractual term. If any of the assumptions used in the Black-Scholes option pricing model changes significantly, stock-based compensation expense may differ materially in the future from that recorded in the current period. In addition, the Company estimates the forfeiture rate based on historical experience and its expectations regarding future pre-vesting termination behavior of employees. To the extent that the actual forfeiture rate is different from this estimate, stock-based compensation expense is adjusted accordingly. The following table presents the weighted-average assumptions for the Black-Scholes option-pricing model used in determining the fair value of options granted (unaudited) : For the three months ended March 31, 2019 2018 Dividend yield —% —% Risk-free interest rate 2.50% - 2.66% 2.46% Expected volatility 106% 89% Expected term (years) 6.08 10

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Event On April 11, 2019, the Company closed a public offering of 5,000,000 shares of common stock at an assumed public offering price of $3.50 per share. The Company received approximately $16.0 million of net proceeds from this offering, after deducting estimated offering expenses payable by the Company. The offering was made pursuant to a registration statement on Form S-3 filed with the Securities Exchange Commission on February 14, 2019. In addition, under the terms of an underwriting agreement entered into with the underwriter of the April 2019 offering, the Company granted the underwriter a 30-day option to purchase up to 750,000 additional shares of common stock. On May 8, 2019, the underwriter purchased 750,000 shares at a price to the underwriter of $3.29 per share pursuant to the exercise of the underwriter's option to purchase additional shares. The aggregate net proceeds were approximately $2.4 million , after deducting underwriting costs and estimated offering expenses.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Accounting	Basis of Presentation The condensed financial statements have been prepared in accordance with United States generally accepted accounting principles (“U.S. GAAP”) for interim financial information, the instructions to Form 10-Q and Regulation S-X. They do not include all the information and notes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 , or any other subsequent period. These financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2018 , included in the Company’s annual report on Form 10-K and filed with the United States Securities and Exchange Commission (“SEC”) on March 25, 2019. Certain prior year amounts have been reclassified for consistency with the current year presentation. These reclassifications had no effect on the reported results of operations.
Use of Estimates	Use of Estimates The preparation of the accompanying condensed financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the condensed financial statements, and the reported amounts of revenue and expenses during the periods reported. Actual results could differ from those estimates.
Liquidity and Substantial Doubt in Going Concern	Liquidity and Substantial Doubt in Going Concern Since inception, the Company has incurred recurring operating losses and negative cash flows from operating activities, and as of March 31, 2019 , had an accumulated deficit of $270.7 million . As of March 31, 2019 , the Company had approximately $11.0 million in cash, cash equivalents and marketable securities. Presently, the Company does not have sufficient cash, cash equivalents and marketable securities to enable it to fund the anticipated level of operations and meet its obligations as they become due within twelve months following the date of issuance of this Quarterly Report on Form 10-Q. The aforementioned factors raise substantial doubt about the Company’s ability to continue as a going concern for a period of one year from the issuance of these financial statements. The financial statements do not include any adjustments that might result from the outcome of this uncertainty. On April 11, 2019, the Company closed a public offering of 5,000,000 shares of common stock at a price to the underwriter of $3.29 per share. On May 8, 2019, the underwriter purchased 750,000 shares at a price to the underwriter of $3.29 per share pursuant to the exercise of the underwriter's option to purchase additional shares. The aggregate net proceeds were approximately $18.4 million , after deducting underwriting costs and estimated offering expenses (See Note 10. Subsequent Event ). The Company plans to raise additional funding through financing, a capital offering, a license or collaboration agreement or a combination of such sources of capital. However, there are no assurances that additional funding will be achieved and that the Company will succeed in its future operations. The Company’s inability to obtain required funding in the near future or its inability to obtain funding on favorable terms will have a material adverse effect on its operations and strategic development plan for future growth. If the Company cannot successfully raise additional capital and implement its strategic development plan, its liquidity, financial condition and business prospects will be materially and adversely affected, and it may have to cease operations. The Company will continue to evaluate its timelines, strategic needs, and working capital requirements. There can be no assurance that if the Company attempts to raise additional capital, it will be successful in doing so on terms acceptable to the Company, or at all. Further, there can be no assurance that it will be able to gain access and/or be able to execute on securing new sources of funding, new development opportunities, successfully obtain regulatory approvals for and commercialize new products, achieve significant product revenues from its products (if approved), or achieve or sustain profitability in the future.
Leases	Leases ASC Topic 842, Leases , requires lessees to recognize right-of-use assets and lease liabilities for most leases on the balance sheet and to provide expanded disclosures about leasing arrangements. The Company adopted Topic 842 effective January 1, 2019 using the optional transition method and did not restate comparative periods. There was no effect on accumulated deficit at adoption. The Company has elected the package of practical expedients to (i) not reassess whether expired or existing contracts are or contain leases, (ii) not reassess the lease classification for any expired or existing leases and (iii) not reassess the accounting for initial direct costs. The adoption of the new leases standard resulted in the following adjustments to the consolidated balance sheet as of January 1, 2019: December 31, 2018 Adoption Impact January 1, 2019 (in thousands) (unaudited; in thousands) Operating lease right-of-use assets $ — $ 6,415 $ 6,415 Operating leases liabilities, current portion $ — $ 945 $ 945 Other accrued liabilities $ 2,414 $ (143 ) $ 2,271 Operating lease liabilities, long-term portion $ — $ 6,900 $ 6,900 Deferred rent $ 1,287 $ (1,287 ) $ — As of December 31, 2018 , the short-term portion of deferred rent was recorded in other accrued liabilities. The adoption impact was a non-cash operating activity for the period ended March 31, 2019. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present. Operating lease liabilities and their corresponding right-of-use assets are recorded based on the present value of lease payments over the expected lease term. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company utilizes its incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term, an amount equal to the lease payments in a similar economic environment. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company considers all highly liquid investments with an original maturity of 90 days or less to be cash equivalents.
Marketable Securities	Marketable Securities Marketable securities generally consist of debt securities with original maturities greater than 90 days and remaining maturities of less than one year. All of the Company's investments are classified as available-for-sale and carried at fair value based upon quoted market price. The change in unrealized gains and losses is reported as a separate component of other comprehensive income (loss) on the statements of operations and comprehensive loss and as a separate component of stockholders' equity on the balance sheets. Interest income includes interest, dividends, accretion and amortization of purchase premiums and discounts and realized gains and losses on sales of securities, if any. The cost of securities sold is based on the specific-identification method. The Company monitors its investment portfolio for potential impairment on a quarterly basis. If the carrying amount of an investment in marketable securities exceeds its fair value and the decline in value is determined to be other-than-temporary, the carrying amount of the security is reduced to fair value and a loss is recognized in operating results for the amount of such decline. In order to determine whether a decline in value is other-than-temporary, the Company evaluates, among other factors, the cause of the impairment, including the creditworthiness of the security issuers, the number of securities in an unrealized loss position, the severity and duration of the unrealized losses, and its intent and ability to hold the security to maturity or forecasted recovery. Investments with original maturities between three and twelve (12) months are considered short-term investments. Investments with original maturities greater than 12 months are considered long-term investments.
Fair Value Instruments	Fair Value Instruments The Company records its financial assets and liabilities at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: • Level I: Inputs which include quoted prices in active markets for identical assets and liabilities. • Level II: Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. • Level III: Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The carrying values of certain assets and liabilities of the Company, such as cash and cash equivalents and accounts payable approximate fair value due to their relatively short maturities. The carrying value of the Company’s short-term financial obligations approximates their fair value as the terms of the borrowing are consistent with current market rates and the duration to maturity is short.
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per common share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, common stock warrants and stock options are considered to be potential dilutive securities but are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented.
Recent Accounting Pronouncements	In August 2018, the FASB issued ASU2018-15, Intangible - Goodwill and Other - Internal-Use Software (Subtopic 350-40) , which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. ASU2018-15 is effective for the Company in the first quarter of 2020. Early adoption is permitted. ASU2018-15 permits either a prospective or retrospective transition approach. The Company is currently evaluating ASU2018-15 to determine the impact to its financial statements and related disclosures. In August 2018, the FASB issued ASU2018-13, Fair Value Measurement (Topic 820) . The new guidance modifies the disclosure requirements on fair value measurements. ASU2018-13 is effective for the Company beginning in the first quarter of 2020 and must be adopted on a modified retrospective basis, with certain exceptions. Early adoption is permitted. The Company does not expect ASU2018-13 to have a significant impact to its financial statements and disclosures. In June 2016, the FASB issued ASU2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments and in November 2018, issued ASU2018-19, Codification Improvements to Topic 326, Financial Instruments - Credit Losses . This new guidance is intended to present credit losses on available for sale debt securities as an allowance rather than as a write-down. Entities are required to apply the standard's provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. ASU2016-13 and ASU2018-19 are effective for the Company in the first quarter of 2020. The Company is currently evaluating ASU2016-13 and ASU2018-19 to determine the impact to its financial statements and disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash to amounts shown in the statement of cash flows: March 31, 2019 March 31, 2018 (unaudited; in thousands) Cash and cash equivalents $ 6,142 $ 3,537 Restricted cash 455 455 Total $ 6,597 $ 3,992
Schedule of Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash to amounts shown in the statement of cash flows: March 31, 2019 March 31, 2018 (unaudited; in thousands) Cash and cash equivalents $ 6,142 $ 3,537 Restricted cash 455 455 Total $ 6,597 $ 3,992
Schedule of Outstanding Common Stock Equivalents Excluded From Computations of Diluted Net Loss per Common Share	The following outstanding common stock equivalents were excluded from the computations of diluted net loss per common share for the periods presented as the effect of including such securities would be antidilutive: March 31, 2019 March 31, 2018 (unaudited) Warrants to purchase common stock 274,524 199,524 Options to purchase common stock 1,456,126 124,379 Total 1,730,650 323,903
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	The adoption of the new leases standard resulted in the following adjustments to the consolidated balance sheet as of January 1, 2019: December 31, 2018 Adoption Impact January 1, 2019 (in thousands) (unaudited; in thousands) Operating lease right-of-use assets $ — $ 6,415 $ 6,415 Operating leases liabilities, current portion $ — $ 945 $ 945 Other accrued liabilities $ 2,414 $ (143 ) $ 2,271 Operating lease liabilities, long-term portion $ — $ 6,900 $ 6,900 Deferred rent $ 1,287 $ (1,287 ) $ —

Cash Equivalents and Investme_2

Cash Equivalents and Investments in Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2019
Cash and Cash Equivalents [Abstract]
Summary of Cash Equivalents and Marketable Securities	The following tables present summaries of the Company's cash equivalents and marketable securities measured at fair value on a recurring basis: Fair Value Measurements Total Quoted prices Significant Significant (unaudited; in thousands) As of March 31, 2019: Money market funds $ 4,905 $ 4,905 $ — $ — Corporate notes and bonds 1,500 — 1,500 — U.S. treasuries 3,396 3,396 — — Total $ 9,801 $ 8,301 $ 1,500 $ — Classified as: Cash equivalents $ 4,905 Marketable securities at fair value 4,896 Total $ 9,801 Fair Value Measurements Total Quoted prices in active market Level I Significant other observable inputs Level II Significant unobservable inputs Level III (in thousands) As of December 31, 2018: Money market funds $ 4,830 $ 4,830 $ — $ — Commercial paper 1,497 — 1,497 — Corporate notes and bonds 6,989 — 6,989 — U.S. treasuries 8,375 8,375 — — Total $ 21,691 $ 13,205 $ 8,486 $ — Classified as: Cash equivalents $ 7,829 Marketable securities at fair value 13,862 Total $ 21,691
Summary of Available-for-sale Fixed Maturity Debt Securities	The following tables summarize the unrealized positions for available-for-sale fixed maturity debt securities disaggregated by class of instrument: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (unaudited; in thousands) As of March 31, 2019: Money market funds $ 4,905 $ — $ — $ 4,905 Corporate notes and bonds 1,500 — — 1,500 U.S. treasuries 3,395 1 — 3,396 Total $ 9,800 $ 1 $ — $ 9,801 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) As of December 31, 2018: Money market funds $ 4,830 $ — $ — $ 4,830 Commercial paper 1,497 — — 1,497 Corporate notes and bonds 6,994 — (5 ) 6,989 U.S. treasuries 8,375 — — 8,375 Total $ 21,696 $ — $ (5 ) $ 21,691

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Schedule of Prepaid Expenses and Other Current Assets	The following table summarizes the Company's prepaid expenses and other current assets for each of the periods presented: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Offering costs $ 517 $ 114 Prepaid insurance 241 45 Other 163 199 Total $ 921 $ 358
Schedule of Other Accrued Liabilities	The following table summarizes the Company’s other accrued liabilities for each of the periods presented: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Construction-in-progress obligations $ 2,969 $ 395 Pre-clinical and clinical study 971 483 Professional service fees 301 112 Contract manufacturing 407 834 Accrued taxes 50 187 Other 606 408 Total $ 5,304 $ 2,419
Schedule of Property and Equipment	The following table summarizes the Company’s property and equipment for each of the periods presented: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Leasehold improvements $ 16,951 $ 16,690 Manufacturing equipment 11,833 10,387 Laboratory and office equipment 1,479 1,434 Computer equipment and software 235 206 Construction-in-progress 12,895 9,558 43,393 38,275 Less: accumulated depreciation (26,524 ) (26,359 ) Total $ 16,869 $ 11,916

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Supplemental Balance Sheet Information	The finance lease obligations were as follows: March 31, 2019 December 31, 2018 (unaudited; in thousands) (in thousands) Finance lease obligations, current portion $ 13 $ 5 Finance lease obligations, long-term portion $ 30 $ 18
Lease, Cost	The components of lease cost were as follows: Description of lease costs Three months ended March 31, 2019 (unaudited; in thousands) Finance Lease Cost Amortization of finance lease right-of-use assets $ 15 Interest on finance lease obligations 9 Operating lease costs 410 Total $ 434 Cash payments for leases were as follows: Description of cash payment Three months ended March 31, 2019 (unaudited; in thousands) Operating cash flows from operating leases $ 436 Operating cash flows from finance leases $ 3 Financing cash flows from finance leases $ 3 Lease term and discount rate were as follows: March 31, 2019 Description of other lease information Operating leases Finance leases (unaudited) Weighted-average remaining lease term 5.49 2.51 Weighted average discount rate 11 % 27 %
Lessee, Operating Lease, Liability, Maturity	Year Operating leases Finance leases (unaudited; in thousands) Remainder of 2019 $ 1,326 $ 18 2020 1,815 24 2021 1,863 14 2022 1,914 3 2023 1,970 — 2024 1,340 — Total undiscounted cash flows 10,228 59 Less: amount representing interest (2,605 ) (16 ) Present value of leased liabilities $ 7,623 $ 43
Finance Lease, Liability, Maturity	As of March 31, 2019 , annual scheduled lease payments were as follows: Year Operating leases Finance leases (unaudited; in thousands) Remainder of 2019 $ 1,326 $ 18 2020 1,815 24 2021 1,863 14 2022 1,914 3 2023 1,970 — 2024 1,340 — Total undiscounted cash flows 10,228 59 Less: amount representing interest (2,605 ) (16 ) Present value of leased liabilities $ 7,623 $ 43

Debt Financing Debt Financing (

Debt Financing Debt Financing (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	The following table is a summary of the Company's build-to-suit obligation as of March 31, 2019 (unaudited; in thousands) : Build-to-suit obligation principal amount $ 6,609 Build-to-suit obligation Purchase Option Fees 760 Less: unamortized Purchase Option Fees (534 ) unamortized fair value of free-standing warrants (173 ) unamortized debt discount (149 ) unamortized debt issuance costs (18 ) Build-to-suit obligation, net of debt issuance costs and discount $ 6,495 Build-to-suit obligation, current portion $ 2,451 Build-to-suit obligation, long-term portion, net of debt issuance costs and discount 4,044 Build-to-suit obligation, net of debt issuance costs and discount $ 6,495
Schedule of Maturities of Long-term Debt	Future minimum payments on the Company’s build-to-suit obligation, including payment of principal and interest and Purchase Option Fees for each year ending December 31 were as follows: Year Principal Interest Purchase Option Fees (unaudited; in thousands) Remainder of 2019 $ 1,815 $ 433 $ — 2020 2,632 367 — 2021 2,162 107 936 Total $ 6,609 $ 907 $ 936

Warrants (Tables)

Warrants (Tables)	3 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
Summary of Warrants Issued and Outstanding	The following table summarizes the warrants issued and outstanding as of March 31, 2019 : Warrants Warrants Issued Warrants Exercised Warrants Expired Warrants Exercise Price Expiration Date (unaudited) PIPE Financing - Series B 195,906 — — — 195,906 $ 31.00 8/19/2021 Hercules - June 2014 1,583 — — — 1,583 $ 176.80 1/27/2020 Hercules - June 2015 2,035 — — — 2,035 $ 147.40 6/23/2020 Trinity - September 2018 75,000 — — — 75,000 $ 3.59 9/25/2025 Total 274,524 — — — 274,524

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option and Award Activity Excluding Inducement Grants	The following table summarizes option and award activity, excluding inducement grants, for the three months ended March 31, 2019 (unaudited) : Shares Available for Grant Number of Shares Subject to Outstanding Options Weighted- Average Exercise Price per Share Weighted- Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value Balance at January 1, 2019 55,799 1,296,157 $ 5.75 9.23 $ — Additional shares reserved 419,056 — $ — Options granted (179,250 ) 179,250 $ 4.13 Options canceled/forfeited/expired 32,243 (32,243 ) $ 5.28 Balance at March 31, 2019 327,848 1,443,164 $ 5.56 9.05 $ 775,606 Exercisable at March 31, 2019 298,777 $ 9.26 8.47 $ 123,891 Vested or expected to vest at March 31, 2019 1,340,746 $ 5.64 9.04 $ 722,306
Summary of Company's Inducement Grant Stock Option Activities	The following table summarizes the Company’s inducement grant stock option activity (unaudited) : Number of Shares Subject to Outstanding Options Weighted- Average Exercise Price per Share Weighted-Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value Balance at January 1, 2019 13,837 $ 20.60 4.52 $ — Options granted — $ — Options canceled/forfeited/expired (875 ) $ 22.80 Balance at March 31, 2019 12,962 $ 20.45 3.51 $ — Exercisable at March 31, 2019 10,357 $ 18.75 2.33 $ — Vested or expected to vest at March 31, 2019 12,788 $ 20.36 3.45 $ —
Summary of Stock-Based Compensation Expense	Total stock-based compensation expense recognized was as follows: Three months ended March 31, 2019 2018 (unaudited; in thousands) Research and development $ 165 $ 67 General and administrative 196 72 Total $ 361 $ 139
Schedule of Weighted-Average Assumptions for the Black-Scholes Option-Pricing Model Used in Determining the Fair Value of Options Granted	The following table presents the weighted-average assumptions for the Black-Scholes option-pricing model used in determining the fair value of options granted (unaudited) : For the three months ended March 31, 2019 2018 Dividend yield —% —% Risk-free interest rate 2.50% - 2.66% 2.46% Expected volatility 106% 89% Expected term (years) 6.08 10

Organization and Basis of Pre_2

Organization and Basis of Presentation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	May 08, 2019	Apr. 11, 2019	May 08, 2019	Apr. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Subsequent Event [Line Items]
Accumulated deficit					$ 270,658	$ 261,232
Cash, cash equivalents and investments					$ 11,000
Subsequent Event
Subsequent Event [Line Items]
Consideration from sale of stock			$ 18,400
Public Stock Offering | Subsequent Event
Subsequent Event [Line Items]
Shares issued in transaction (in shares)		5,000,000
Price of stock sold (in USD per share)		$ 3.50
Consideration from sale of stock		$ 16,000
Over-Allotment Option | Subsequent Event
Subsequent Event [Line Items]
Shares issued in transaction (in shares)	750,000			750,000
Price of stock sold (in USD per share)	$ 3.29		$ 3.29
Consideration from sale of stock	$ 2,400

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Cash and Cash Equivalents [Line Items]
Restricted cash	$ 455	$ 455	$ 455
Deposit, Building Lease
Cash and Cash Equivalents [Line Items]
Restricted cash	300	300
Deposit, Utility Provider
Cash and Cash Equivalents [Line Items]
Restricted cash	100	100
Corporate Purchasing Cards
Cash and Cash Equivalents [Line Items]
Restricted cash	$ 35,000	$ 35

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Lease Standards (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 6,219	$ 6,415
Operating leases liabilities, current portion	985	945
Other accrued liabilities		2,271	$ 2,414
Operating lease liabilities, long-term portion	6,638	6,900
Deferred rent	$ 0	0	$ 1,287
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets		6,415
Operating leases liabilities, current portion		945
Other accrued liabilities		(143)
Operating lease liabilities, long-term portion		6,900
Deferred rent		$ (1,287)

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Summary of Reconciliation of Cash and Cash Equivalents, and Restricted Cash (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 6,142	$ 9,140	$ 3,537
Restricted cash	455	455	455
Total	$ 6,597	$ 9,595	$ 3,992	$ 12,106

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Outstanding Common Stock Equivalents Excluded From Computations of Diluted Net Loss per Common Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock excluded from computation of diluted net loss per share	1,730,650	323,903
Warrants to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock excluded from computation of diluted net loss per share	274,524	199,524
Options to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock excluded from computation of diluted net loss per share	1,456,126	124,379

Cash Equivalents and Investme_3

Cash Equivalents and Investments in Marketable Securities - Summary of Cash Equivalents and Investments Carried at Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	$ 9,801	$ 21,691
Total	11,000
Recurring
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	9,801	21,691
Cash equivalents	4,905	7,829
Marketable securities at fair value	4,896	13,862
Total	9,801	21,691
Recurring | Level I
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	8,301	13,205
Recurring | Level II
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	1,500	8,486
Recurring | Level III
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	0	0
Money Market Funds
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	4,905	4,830
Money Market Funds | Recurring
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	4,905	4,830
Money Market Funds | Recurring | Level I
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	4,905	4,830
Money Market Funds | Recurring | Level II
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	0	0
Money Market Funds | Recurring | Level III
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	0	0
Commercial Paper
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value		1,497
Commercial Paper | Recurring
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value		1,497
Commercial Paper | Recurring | Level I
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value		0
Commercial Paper | Recurring | Level II
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value		1,497
Commercial Paper | Recurring | Level III
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value		0
Corporate Notes and Bonds
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	1,500	6,989
Corporate Notes and Bonds | Recurring
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	1,500	6,989
Corporate Notes and Bonds | Recurring | Level I
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	0	0
Corporate Notes and Bonds | Recurring | Level II
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	1,500	6,989
Corporate Notes and Bonds | Recurring | Level III
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	0	0
U.S. Treasuries
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	3,396	8,375
U.S. Treasuries | Recurring
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	3,396	8,375
U.S. Treasuries | Recurring | Level I
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	3,396	8,375
U.S. Treasuries | Recurring | Level II
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	0	0
U.S. Treasuries | Recurring | Level III
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Fair Value	$ 0	$ 0

Cash Equivalents and Investme_4

Cash Equivalents and Investments in Marketable Securities - Summary of Investment Available for Sale (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 9,800	$ 21,696
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	(5)
Fair Value	9,801	21,691
Money Market Funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,905	4,830
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	4,905	4,830
Commercial Paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		1,497
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		1,497
Corporate Notes and Bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,500	6,994
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(5)
Fair Value	1,500	6,989
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,395	8,375
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	0
Fair Value	$ 3,396	$ 8,375

Balance Sheet Components - Prep

Balance Sheet Components - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Offering costs	$ 517	$ 114
Prepaid insurance	241	45
Other	163	199
Prepaid expenses and other current assets	$ 921	$ 358

Balance Sheet Components - Othe

Balance Sheet Components - Other Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Construction-in-progress obligations	$ 2,969	$ 395
Pre-clinical and clinical study	971	483
Professional service fees	301	112
Contract manufacturing	407	834
Accrued taxes	50	187
Other	606	408
Total	$ 5,304	$ 2,419

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 43,393	$ 38,275
Less: accumulated depreciation	(26,524)	(26,359)
Property and equipment, net	16,869	11,916
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	16,951	16,690
Manufacturing Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	11,833	10,387
Laboratory and Office Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,479	1,434
Computer Equipment and Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	235	206
Construction in Progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 12,895	$ 9,558

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 200	$ 200
Property and equipment	16,869		$ 11,916
Property and equipment, gross	43,393		38,275
Finance lease, accumulated amortization	15
Accumulated capitalized interest costs	700
Assets Held Under Finance Leases
Property, Plant and Equipment [Line Items]
Property and equipment	43
Assets Held Under Finance Leases
Property, Plant and Equipment [Line Items]
Property and equipment			24
Construction in Progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,895		$ 9,558
GERMANY
Property, Plant and Equipment [Line Items]
Property and equipment, gross	6,200
GERMANY | Construction in Progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 9,700

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	Sep. 01, 2017	Mar. 31, 2019	Jan. 31, 2018
Lessee, Lease, Description [Line Items]
Renewal term		60 months
Monthly base rent	$ 136
Incentive rent abatements		$ 300
Landlord's tenant improvements		$ 1,000
Telephone Equipment
Lessee, Lease, Description [Line Items]
Term of lease			3 years

Leases - Finance Lease Obligati

Leases - Finance Lease Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Finance lease obligations, current portion	$ 13
Finance lease obligations, current portion		$ 5
Finance lease obligations, long-term portion	$ 30
Finance lease obligations, long-term portion		$ 18

Leases - Description of Lease C

Leases - Description of Lease Costs (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Amortization of finance lease right-of-use assets	$ 15
Interest on finance lease obligations	9
Operating lease costs	410
Total	$ 434

Leases - Description of Cash Pa

Leases - Description of Cash Payment (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 436
Operating cash flows from finance leases	3
Financing cash flows from finance leases	$ 3

Leases - Description of Other L

Leases - Description of Other Lease Information (Details)	Mar. 31, 2019
Leases [Abstract]
Weighted average remaining lease term, operating lease	5 years 5 months 27 days
Weighted average remaining lease term, financing lease	2 years 6 months 4 days
Weighted average discount rate, operating lease	11.00%
Weighted average discount rate, finance lease	27.00%

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Details) $ in Thousands	Mar. 31, 2019USD ($)
Operating leases
2019	$ 1,326
2020	1,815
2021	1,863
2022	1,914
2023	1,970
2024	1,340
Total undiscounted cash flows	10,228
Less: amount representing interest	(2,605)
Present value of leased liabilities	7,623
Finance leases
Remainder of 2019	18
2020	24
2021	14
2022	3
2023	0
2024	0
Total undiscounted cash flows	59
Less: amount representing interest	(16)
Present value of leased liabilities	$ 43

Debt Financing - Additional Inf

Debt Financing - Additional Information (Detail) - USD ($)	Mar. 20, 2020	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2014	Jun. 30, 2014	Mar. 31, 2019	Mar. 31, 2018	Sep. 25, 2018
Debt Instrument [Line Items]
Restocking fee						6.00%
Payment for loan			$ 160,000
Common stock issued (in shares)		11,973,039				11,973,039
Common stock warrant exercise price			$ 3.59
Property and equipment, gross		$ 38,275,000				$ 43,393,000
Accumulated capitalized interest costs						700,000
Interest expense							$ 200,000
Trinity Capital Fund III, L.P.
Debt Instrument [Line Items]
Common stock warrant expiration date			Sep. 25, 2025
Proceeds from issuance of warrants			$ 243,000
Trinity Capital Fund III, L.P. | Warrants to Purchase Common Stock
Debt Instrument [Line Items]
Common stock issued (in shares)			75,000
Trinity Capital Fund III, L.P.
Debt Instrument [Line Items]
Proceeds from line of credit		2,600,000	$ 2,700,000
Payment for loan		90,000
Proceeds from line of credit, withheld by lender		$ 200,000	$ 300,000
Debt interest rate		9.68%	9.43%
Debt effective interest rate		19.58%	26.28%
Build to Suit Obligation | Trinity Capital Fund III, L.P.
Debt Instrument [Line Items]
Build-to-suit obligation, aggregate principal amount			$ 14,000,000
Build to Suit Obligation | Trinity Capital Fund III, L.P.
Debt Instrument [Line Items]
Build-to-suit obligation, aggregate principal amount			14,000,000
Build-to-suit obligation			5,000,000			$ 6,500,000
Incremental drawdowns, minimum			500,000
Debt instrument term						36 months
Second drawdown		$ 2,800,000
Interest payable						$ 71,000
Build-to-Suit Obligation, Condition One | Trinity Capital Fund III, L.P.
Debt Instrument [Line Items]
Purchase percentage of equipment cost						12.00%
Build-to-Suit Obligation, Condition Two | Trinity Capital Fund III, L.P.
Debt Instrument [Line Items]
Purchase percentage of equipment cost						4.00%
Senior Secured Term Loan with Hercules
Debt Instrument [Line Items]
Payment for loan			$ 2,000,000
Senior Subordinated Notes | Amended Hercules Secured Term Loan
Debt Instrument [Line Items]
Debt effective interest rate				7.95%	7.95%
Debt face amount				$ 15,000,000	$ 15,000,000
Debt payment, due and payable date						Dec. 1, 2018
Debt variable interest rate					7.95%
Debt additional variable interest rate decrease				5.25%
Additional debt end of term charge								$ 400,000
Construction in Progress
Debt Instrument [Line Items]
Property and equipment, gross		$ 9,558,000				$ 12,895,000
GERMANY
Debt Instrument [Line Items]
Property and equipment, gross						6,200,000
GERMANY | Construction in Progress
Debt Instrument [Line Items]
Property and equipment, gross						$ 9,700,000
Forecast | Build to Suit Obligation | Trinity Capital Fund III, L.P.
Debt Instrument [Line Items]
Non-utilization fee percentage	3.00%

Debt Financing Schedule of Long

Debt Financing Schedule of Long-term Debt Instruments (Details) - Build to Suit Obligation $ in Thousands	Mar. 31, 2019USD ($)
Debt Instrument [Line Items]
Build-to-suit obligation principal amount	$ 6,609
Build-to-suit obligation Purchase Option Fees	760
Less: unamortized Purchase Option Fees	(534)
unamortized fair value of free-standing warrants	(173)
unamortized debt discount	(149)
unamortized debt issuance costs	(18)
Build-to-suit obligation, net of debt issuance costs and discount	6,495
Build-to-suit obligation, current portion	2,451
Build-to-suit obligation, long-term portion, net of debt issuance costs and discount	$ 4,044

Debt Financing Future Minimum P

Debt Financing Future Minimum Payments (Details) $ in Thousands	Mar. 31, 2019USD ($)
Debt Disclosure [Abstract]
Remainder of 2019, Principal	$ 1,815
2020, Principal	2,632
2021, Principal	2,162
Total, Principal	6,609
Remainder of 2019, Interest	433
2020, Interest	367
2021, Interest	107
Total, Interest	907
Remainder of 2019, Termination Fees	0
2020, Termination Fees	0
2021, Termination Fees	936
Total, Termination Fees	$ 936

Warrants (Detail)

Warrants (Detail)	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Warrants Outstanding Rollforward [Roll Forward]
Warrants Outstanding	274,524
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	274,524
Hercules - June 2014
Warrants Outstanding Rollforward [Roll Forward]
Warrants Outstanding	1,583
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	1,583
Exercise Price (in USD per share) | $ / shares	$ 176.80
Expiration Date	Jan. 27, 2020
Hercules - June 2015
Warrants Outstanding Rollforward [Roll Forward]
Warrants Outstanding	2,035
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	2,035
Exercise Price (in USD per share) | $ / shares	$ 147.40
Expiration Date	Jun. 23, 2020
Trinity - September 2018
Warrants Outstanding Rollforward [Roll Forward]
Warrants Outstanding	75,000
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	75,000
Exercise Price (in USD per share) | $ / shares	$ 3.59
Expiration Date	Sep. 25, 2025
Private Investment in Public Equity (PIPE) | Series B
Warrants Outstanding Rollforward [Roll Forward]
Warrants Outstanding	195,906
Warrants Issued	0
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	195,906
Exercise Price (in USD per share) | $ / shares	$ 31
Expiration Date	Aug. 19, 2021

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended			3 Months Ended	10 Months Ended	12 Months Ended
	Feb. 28, 2019	Sep. 30, 2018	May 31, 2018	Mar. 31, 2019	Feb. 28, 2019	Dec. 31, 2018
Other Commitments [Line Items]
Purchase commitments related to fixed assets					$ 13.5
Purchase commitment period					18 months
Payments for construction-in-progress for equipment manufacturing				$ 5.9
Cancellation fees		50.00%
Construction agreement and transfer fees				4.1
Payment				$ 0.6
Minimum
Other Commitments [Line Items]
Annual fees		$ 1
Termination fees		1
Maximum
Other Commitments [Line Items]
Annual fees		14
Termination fees		$ 1.4
Employee Stock Option | Minimum
Other Commitments [Line Items]
Vesting rights upon termination				25.00%
Employee Stock Option | Maximum
Other Commitments [Line Items]
Vesting rights upon termination				100.00%
Commercial Coating and Primary Packaging System
Other Commitments [Line Items]
Purchase commitments related to fixed assets	$ 1.3		$ 12.2
Equipment, Patch Assembly and Applicator, Retainer Machinery
Other Commitments [Line Items]
Purchase commitments related to fixed assets						$ 3.6
Aggregate purchase price paid						$ 1.6

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant (in shares)	327,848	55,799
Stock option awards granted (in shares)	179,250
Unrecognized stock-based compensation expense	$ 3.7
Weighted-average period of unrecognized stock-based compensation expense	3 years 1 month 21 days
New Employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option awards granted (in shares)	32,500
Vesting percentage	25.00%
Vesting rights	Options vest at a rate of 25% of the shares on the first anniversary of the commencement of such employee’s employment with the Company, and then one forty-eighth (1/48) of the shares monthly thereafter subject to such employee’s continued service.
Amended and Restated 2014 Equity and Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (in shares)	1,767,229
Options vested period	4 years
Shares available for grant (in shares)	327,848
Amended and Restated 2014 Equity and Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options grant period	10 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option and Award Activity Excluding Inducement Grants (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Shares Available for Grant
Beginning balance (in shares)	55,799
Additional shares reserved (in shares)	419,056
Options granted (in shares)	(179,250)
Options canceled/forfeited/expired (in shares)	32,243
Ending balance (in shares)	327,848	55,799
Number of Shares Subject to outstanding Options
Beginning balance (in shares)	1,296,157
Options granted (in shares)	179,250
Options canceled/forfeited/expired (in shares)	(32,243)
Ending balance (in shares)	1,443,164	1,296,157
Exercisable (in shares)	298,777
Vested or expected to vest (in shares)	1,340,746
Weighted-Average Exercise Price per Share
Beginning balance (in USD per share)	$ 5.75
Options granted (in USD per share)	4.13
Option canceled/forfeited/expired (in USD per share)	5.28
Ending balance (in USD per share)	5.56	$ 5.75
Exercisable (in USD per share)	9.26
Vested or expected to vest (in USD per share)	$ 5.64
Weighted-Average Remaining Contractual Term (In Years)
Weighted-average remaining contractual term	9 years 18 days	9 years 2 months 23 days
Exercisable	8 years 5 months 19 days
Vested or expected to vest	9 years 15 days
Aggregate Intrinsic Value
Balance	$ 775,606
Exercisable	123,891
Vested or expected to vest	$ 722,306

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Company's Inducement Grant Stock Option Activities (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Number of Shares Subject to outstanding Options
Beginning balance (in shares)	1,296,157
Options granted (in shares)	179,250
Options canceled/forfeited/expired (in shares)	(32,243)
Ending balance (in shares)	1,443,164	1,296,157
Exercisable (in shares)	298,777
Vested or expected to vest (in shares)	1,340,746
Weighted-Average Exercise Price per Share
Beginning balance (in USD per share)	$ 5.75
Options granted (in USD per share)	4.13
Option canceled/forfeited/expired (in USD per share)	5.28
Ending balance (in USD per share)	5.56	$ 5.75
Exercisable (in USD per share)	9.26
Vested or expected to vest (in USD per share)	$ 5.64
Weighted-Average Remaining Contractual Term (In Years)
Weighted-average remaining contractual term	9 years 18 days	9 years 2 months 23 days
Exercisable	8 years 5 months 19 days
Vested or expected to vest	9 years 15 days
Aggregate Intrinsic Value
Balance	$ 775,606
Exercisable	123,891
Vested or expected to vest	$ 722,306
Inducement Grant
Number of Shares Subject to outstanding Options
Beginning balance (in shares)	13,837
Options granted (in shares)	0
Options canceled/forfeited/expired (in shares)	(875)
Ending balance (in shares)	12,962	13,837
Exercisable (in shares)	10,357
Vested or expected to vest (in shares)	12,788
Weighted-Average Exercise Price per Share
Beginning balance (in USD per share)	$ 20.60
Options granted (in USD per share)	0
Option canceled/forfeited/expired (in USD per share)	22.80
Ending balance (in USD per share)	20.45	$ 20.60
Exercisable (in USD per share)	18.75
Vested or expected to vest (in USD per share)	$ 20.36
Weighted-Average Remaining Contractual Term (In Years)
Weighted-average remaining contractual term	3 years 6 months 4 days	4 years 6 months 7 days
Exercisable	2 years 3 months 29 days
Vested or expected to vest	3 years 5 months 12 days
Aggregate Intrinsic Value
Balance	$ 0
Exercisable	0
Vested or expected to vest	$ 0

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 361	$ 139
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	165	67
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 196	$ 72

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Weighted-Average Assumptions for the Black-Scholes Option-Pricing Model Used in Determining the Fair Value of Options Granted (Detail)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Dividend yield	0.00%	0.00%
Risk free interest rate, minimum	2.50%
Risk free interest rate, maximum	2.66%
Risk-free interest rate		2.46%
Expected volatility	106.00%	89.00%
Expected term	6 years 29 days	10 years

Subsequent Event (Details)

Subsequent Event (Details) - Subsequent Event - USD ($) $ / shares in Units, $ in Millions	May 08, 2019	Apr. 11, 2019	May 08, 2019	Apr. 30, 2019
Subsequent Event [Line Items]
Consideration from sale of stock			$ 18.4
Public Stock Offering
Subsequent Event [Line Items]
Shares issued in transaction (in shares)		5,000,000
Price of stock sold (in USD per share)		$ 3.50
Consideration from sale of stock		$ 16
Over-Allotment Option
Subsequent Event [Line Items]
Shares issued in transaction (in shares)	750,000			750,000
Price of stock sold (in USD per share)	$ 3.29		$ 3.29
Consideration from sale of stock	$ 2.4