Zosano Pharma (ZSANQ) 10-Q 9 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 02, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	ZSAN
Entity Registrant Name	Zosano Pharma Corp
Entity Central Index Key	1,587,221
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		11,973,039

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 16,197	$ 11,651
Short-term investments in marketable securities at fair value	21,441	0
Prepaid expenses and other current assets	869	1,742
Total current assets	38,507	13,393
Restricted cash	35	35
Property and equipment, net	6,132	4,152
Other long-term assets	552	420
Total assets	45,226	18,000
Current liabilities:
Accounts payable	2,391	1,511
Accrued compensation	1,434	1,571
Deferred revenue	62	0
Secured promissory note (including accrued interest), net of issuance costs	3,600	6,687
Other accrued liabilities	741	688
Total current liabilities	8,228	10,457
Deferred rent	918	495
Total liabilities	9,146	10,952
Commitments and contingencies (note 6)
Stockholders' equity:
Preferred stock, $0.0001 par value, 5,000,000 shares authorized as of June 30, 2018 and December 31, 2017; none issued and outstanding as of June 30, 2018 and December 31, 2017	0	0
Common stock, $0.0001 par value; 250,000,000 and 100,000,000 shares authorized as of June 30, 2018 and December 31, 2017, respectively; 11,973,039 and 1,973,039 shares issued and outstanding as of June 30, 2018 and December 31, 2017, respectively	1	0
Additional paid-in capital	278,995	232,922
Accumulated deficit	(242,916)	(225,874)
Stockholders' equity	36,080	7,048
Total liabilities and stockholders' equity	$ 45,226	$ 18,000

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	250,000,000	100,000,000
Common stock, shares issued	11,973,039	1,973,039
Common stock, shares outstanding	11,973,039	1,973,039

Condensed Statements of Operati

Condensed Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0
Operating expenses:
Research and development	6,533	4,363	12,339	8,989
General and administrative	2,272	2,188	4,532	4,310
Total operating expenses	8,805	6,551	16,871	13,299
Loss from operations	(8,805)	(6,551)	(16,871)	(13,299)
Other income (expense):
Interest expense, net	(33)	(207)	(174)	(454)
Other income, net	2	12	3	10
Net loss	$ (8,836)	$ (6,746)	$ (17,042)	$ (13,743)
Net loss per common share - basic and diluted	$ (0.75)	$ (3.44)	$ (2.47)	$ (9.22)
Weighted-average shares used in computing net loss per common share - basic and diluted	11,753	1,960	6,890	1,491

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net loss	$ (17,042)	$ (13,743)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	391	1,261
Stock-based compensation	469	416
Gain on sale of equipment	0	(13)
Gross unrealized losses of marketable securities	14	0
Amortization of debt discount/accretion of premium	(5)	(11)
Accretion of interest	36	48
Deferred rent	515	75
Change in operating assets and liabilities:
Interest receivable	56	0
Prepaid expenses and other assets	579	(1,156)
Accounts payable	615	(236)
Accrued compensation and other accrued liabilities	(83)	(766)
Deferred revenue	62	0
Net cash used in operating activities	(14,393)	(14,125)
Cash flows from investing activities:
Purchase of property and equipment	(2,106)	(625)
Proceeds from sales of property and equipment	0	22
Purchase of marketable securities	(37,475)	(7,071)
Proceeds from maturities of marketable securities	16,000	0
Net cash used in investing activities	(23,581)	(7,674)
Cash flows from financing activities:
Proceeds from public offering of securities, net of underwriting commissions, discounts and other offering costs	45,603	26,623
Proceeds from exercise of warrants and issuance of common stock	0	4,041
Payment of loan principal	(3,083)	(2,846)
Proceeds from exercise of stock options and issuance of common stock	0	137
Net cash provided by financing activities	42,520	27,955
Net increase in cash and cash equivalents	4,546	6,156
Cash and cash equivalents at beginning of period	11,686	15,038
Cash and cash equivalents at end of period	16,232	21,194
Supplemental cash flow information:
Interest paid	203	540
Acquisition of property and equipment under accounts payable	264	7
Offering costs accrued but not yet paid	$ 98	$ 0

Organization and Basis of Prese

Organization and Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. 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 our proprietary Adhesive Dermally-Applied Microarray, or ADAM™, technology. In February 2017, the Company announced positive results from its ZOTRIP pivotal efficacy trial, or ZOTRIP trial, that evaluated M207, which is its proprietary formulation of zolmitriptan delivered via the Company’s ADAM technology, as an acute treatment for migraine. The Company is focused on developing products where rapid administration of established molecules with known safety and efficacy profiles provides an increased benefit to patients, for markets where patients remain underserved by existing therapies. The Company anticipates that many of our current and future development programs may enable the Company to utilize a regulatory pathway that would streamline clinical development and accelerate the path towards commercialization. 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 S-X. Form 10-K On January 23, 2018, the Company’s stockholders approved an increase to the number of authorized shares of the Company’s common stock from 100,000,000 to 250,000,000 shares. On January 23, 2018, the board of directors approved a 1-for-20 (pre-split) Liquidity As of June 30, 2018, the Company has an accumulated deficit of $242.9 million, as well as recurring operating losses and negative cash flows from operating activities. Cash and cash equivalents at June 30, 2018 were approximately $16.2 million and short-term investments of $21.4 million. On April 3, 2018, the Company closed a public offering of 10,000,000 shares of common stock at a public offering price of $5.00 per share. The Company received gross proceeds of $50.0 million and approximately $45.6 million of net proceeds from the offering and plans to use the net proceeds from the offering to complete the long-term safety study of M207, and for working capital and general corporate purposes. The Company believes the completion of the public offering will allow it to continue executing on the timely filing of its NDA for M207, which it expects will occur in the fourth quarter of 2019. We expect cash and cash equivalents and investments will be sufficient to enable us to fund our anticipated level of operations based on our current operating plans beyond twelve months following the date of issuance of this Quarterly Report on From 10-Q. The Company has financed its operations through the sale of equity securities and debt financing. To date, none of the Company’s product candidates have been approved by the United States Food and Drug Administration for sale. The Company will continue to require additional financing to develop its product candidate, develop additional product candidates and fund operating losses. Management intends to seek capital to support the Company’s initiatives through financing activities such as public or private offerings of its common stock, and/or preferred stock offerings, issuances of debt and convertible debt instruments and collaborative or other arrangements with corporate partners. However, if such financing is not available at adequate levels or on acceptable terms, the Company could be required to significantly reduce its operating expenses and delay, reduce the scope of or eliminate some of its development programs, out-license The Company will continue to evaluate its timelines, strategic needs, and balance sheet 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, or achieve or sustain profitability in the future.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Significant Accounting Policies There have been no material changes to the Company’s significant accounting policies during the six months ended June 30, 2018, as compared to the significant accounting policies described in Note 2 of the “Notes to Financial Statements” in the Company’s Annual Report on Form 10-K 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. Cash and Cash Equivalents and Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash to amounts shown in the statement of cash flows in thousand: June 30, 2018 2017 Cash and cash equivalents $ 16,197 $ 21,159 Restricted cash 35 35 $ 16,232 $ 21,194 Restricted Cash The Company’s restricted cash consists of funds set aside by a contractual pledge and security agreement with a bank whereby $35,000 is held as a security for corporate purchasing cards. Marketable Securities The Company classifies its investments in marketable securities as available-for available-for-sale 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 1: Inputs which include quoted prices in active markets for identical assets and liabilities. • Level 2: 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 3: 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, accounts receivable, and accounts payable, approximate fair value due to their relatively short maturities. The carrying value of the Company’s short-term notes payable approximates their fair value as the terms of the borrowing are consistent with current market rates and the duration to maturity is short. Revenue Effective January 1, 2018, the Company adopted Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers. In accordance with ASC Topic 606, the Company recognizes revenue when the customer obtains control of promised goods or services, in an amount that reflects the consideration which it expects to receive in exchange for those goods and services. To determine revenue recognition for arrangements that the Company deems are within the scope of ASC Topic 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) calculate transfer price; (iv) allocate the transaction price to the performance obligation in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. Deferred Revenue Deferred revenue consists of amounts related to fees resulting from feasibility research projects received prior to satisfying the revenue recognition criteria (see, Revenue) and are recognized as deferred revenue in our balance sheet. Amounts are recognized as revenue upon satisfaction of the performance obligation as prescribed under ASC Topic 606. Research and Development Expenses Research and development costs are charged to expense as incurred and consist of costs related to (i) furthering the Company’s research and development efforts, and (ii) designing and manufacturing products that incorporate the Company’s ADAM technology for the Company’s clinical and nonclinical studies. 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 common stock equivalents. Diluted earnings per common share is computed by giving effect to all potentially dilutive common stock equivalents outstanding for the period. For purposes of this calculation, warrants and options to purchase common stock are considered potentially dilutive common stock equivalents. For the six months ended June 30, 2018 and 2017, diluted net loss per common share was the same as basic net loss per common share since the effect of inclusion of potentially dilutive common stock equivalents would have an antidilutive effect due to the loss reported. 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: June 30, 2018 2017 Warrants to purchase common stock 199,524 347,311 Options to purchase common stock 1,186,318 109,173 1,385,842 456,484 Recent Accounting Pronouncements In June 2018, the FASB issued ASU No. 2018-07, Compensation – Stock Compensation (Topic 718); Improvements to Nonemployee Share-Based Payment Accounting In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815), (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. 2016-13 2016-13 In February 2016, the FASB issued ASU 2016-02, Leases right-of-use

Cash, Cash Equivalents and Inve

Cash, Cash Equivalents and Investments in Marketable Securities	6 Months Ended
	Jun. 30, 2018
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Investments in Marketable Securities	3. Cash, Cash Equivalents and Investments in Marketable Securities As June 30, 2018 and December 31, 2017, cash, cash equivalent, and investments in marketable securities, comprised of funds in depository, money market accounts, U.S. treasury securities, commercial paper, and corporate bonds. The Company classifies all highly liquid investments with maturities of three months or less at the date of purchase as cash equivalents. The following table presents cash equivalents and investments carried at fair value in accordance with the fair value hierarchy defined in Note 2. Fair Value Measurements Quoted prices in active market Level I Significant other observable inputs Level II Significant unobservable inputs Level III (unaudited; in thousands) As of June 30, 2018: Cash and restricted cash, included in cash equivalents (1) $ 1,893 Total Money market funds, included in cash equivalents 5,109 5,109 — — Commercial paper, included in cash equivalents 5,733 — 5,733 — U.S. treasuries, included in cash equivalents 1,000 1,000 — — U.S. government agencies, included in cash equivalents 2,497 — 2,497 — Commercial paper 5,205 — 5,205 — Corporate notes and bonds 6,482 — 6,482 — U.S. treasuries 9,754 9,754 — — Total $ 35,780 $ 15,863 $ 19,917 — As of December 31, 2017: Cash and restricted cash, included in cash equivalents (1) $ 4,587 Total Money market funds, included in cash equivalents 6,414 6,414 — — U.S. government agencies, included in cash equivalents 650 — 650 — Total $ 7,064 $ 6,414 $ 650 — (1) Not subject to leveling As of June 30, 2018 and December 31, 2017 available-for-sale June 30, 2018 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (unaudited; in thousands) Commercial paper $ 10,943 — (5 ) $ 10,938 Corporate notes and bonds 6,489 — (7 ) 6,482 U.S. Treasuries 10,756 — (2 ) 10,754 U.S. Government agencies 2,497 — — 2,497 $ 30,685 $ — $ (14 ) $ 30,671 December 31, 2017 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) U.S. government agency bonds $ 650 — — $ 650 $ 650 $ — $ — $ 650

Property and Equipment

Property and Equipment	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Property and Equipment	4. Property and Equipment The following summarizes the Company’s property and equipment for each of the periods presented: June 30, 2018 December 31, 2017 (unaudited; in thousands) Laboratory and office equipment $ 1,343 $ 1,159 Manufacturing equipment 10,423 10,387 Computer equipment and software 223 209 Leasehold improvements 16,460 15,660 Construction in progress 3,637 2,351 32,086 29,766 Less: accumulated depreciation (25,954 ) (25,614 ) $ 6,132 $ 4,152 Depreciation and amortization expense was approximately $0.2 million and $0.6 million for the three months ended June 30, 2018 and 2017, respectively. Depreciation and amortization expense was $0.4 million and $1.3 million for the six months ended June 30, 2018 and 2017, respectively.

Debt Financing

Debt Financing	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt Financing	5. Debt Financing Senior Secured Term Loan with Hercules The Company entered into a loan and security agreement with Hercules Capital Inc, (“Hercules”). Hercules provided the Company a $15 million loan (“Hercules Term Loan”) of which equal installment payments of principal and interest are due monthly, with all outstanding amounts due and payable on December 1, 2018. The Hercules Term Loan bears 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%. The interest rate on the Hercules Term Loan was 7.95% as of June 30, 2018 and December 31, 2017. On June 1, 2017, the Company paid a $100,000 legacy end of term charge and is required to pay a $351,135 end of term charge on the earlier of loan maturity or at the date the Company prepays the Hercules Term Loan. The Company may prepay all, but not less than all, of the Hercules Term Loan with no prepayment charge. The Hercules Term Loan is secured by a first priority security interest and lien in and to all of the Company’s tangible and intangible properties and assets, including intellectual properties. The following is a summary of the Company’s debt, net of unamortized debt discount and issuance costs for the periods presented: June 30, December 31, 2018 2017 (unaudited; in thousands) Principal amount $ 3,233 $ 6,316 Less: unamortized debt issuance costs (2 ) (10 ) unamortized fair value of free standing warrant (4 ) (18 ) Plus: unamortized fair value debt premium 8 35 accrued terminal interest 344 320 accrued interest 21 44 Secured promissory note, net of unamortized debt issuance cost and premium, current $ 3,600 $ 6,687 For the three and six months ended June 30, 2018, the Company recorded total interest expense of $0.1 million and $0.3 million, respectively. For the three and six months ended June 30, 2017, the Company recorded interest expense of $0.2 million and $0.5 million, respectively, related to the Hercules Term Loan.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies The Company is not party to any material pending legal proceedings. However, the Company may from time to time become involved in litigation relating to claims arising in the ordinary course of business. Operating lease The Company has an operating lease with BMR-34790 Under the Seventh Amendment, the Company extended the term of the lease for the Company’s headquarters in Fremont, California through August 31, 2024, with an option to further extend the lease for an additional 65 months, subject to certain terms and conditions. The Company has agreed to pay a monthly base rent of $136,191 for the period commencing September 1, 2017, and ending on August 31, 2018, with an increase on September 1, 2018, and annual increases on September 1 of each subsequent year until the lease year beginning September 1, 2023. The Seventh Amendment also provides for rent abatements, subject to certain conditions, totaling $275,552 and certain tenant improvements to be completed at the Landlord’s expense (not to exceed $975,000 or, under certain conditions, $1,100,000). The Company will incur additional expense of approximately $0.4 million under the lease in connection with roof repairs that will be treated as additional rent and paid over the term of the lease. The Eighth Amendment extended the deadline for the Company to cause certain tenant improvements to be completed at the landlord’s expense from May 30, 2018 to September 30, 2018. No change to the financial statements resulted from the terms of the Eighth Amendment. For the three and six months ended June 30, 2018, the Company recorded rental expense under the related party operating lease of $0.4 million and $0.8 million, respectively. For the three and six months ended June 30, 2017, the Company recorded rental expense under the related party operating lease of $0.2 million and $0.4 million, respectively. As of June 30, 2018, future minimum payments under the Company’s non-cancelable Total (unaudited; in thousands) Remaining of 2018 $ 833 2019 1,754 2020 1,807 2021 1,861 2022 1,914 2023 and thereafter 3,310 $ 11,479 Severance obligations The Company has entered into employment agreements with some of its executive officers. Generally, the terms of these agreements provide that, 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. On May 15, 2018, Georgia Erbez resigned as Chief Business Officer and Chief Financial Officer. Pursuant to the terms of a Separation Agreement entered into May 10, 2018, the Company agreed to pay severance totaling approximately $201,000, including base salary and benefit continuation coverage, for the six months following the separation date. Accordingly, as of June 30, 2018, the Company has approximately $152,000 of remaining severance related to this arrangement accrued and unpaid. In addition, 25% of the unvested portion of Ms. Erbez’ equity awards at the time of her resignation were accelerated. Her vested options remain exercisable for a period of eighteen months following her resignation. On May 8, 2017, Konstantinos Alataris resigned as President and Chief Executive Officer. Pursuant to the terms of a Separation Agreement, the Company agreed to pay severance totaling approximately $252,000, including base salary and benefit continuation coverage, for six months following the separation date. As of June 30, 2018, the Company had no severance due to Dr. Alataris related to his separation agreement. Other commitments As of June 30, 2018, the Company has an equipment purchase commitment related to its pre-commercialization

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2018
Federal Home Loan Banks [Abstract]
Stockholders' Equity	7. Stockholders’ Equity On January 24, 2018, the Company amended its certificate of incorporation to increase the number of shares of common stock authorized for issuance from 100,000,000 to 250,000,000. On January 25, 2018, we effected a 1-for-20 Equity Line of Credit On October 20, 2017, the Company entered into a purchase agreement and a registration rights agreement with an accredited investor, Lincoln Park Capital Fund, LLC (“Lincoln Park”), providing for the purchase of up to $35.0 million worth of the Company’s common stock over the term of the purchase agreement (the “Equity Line of Credit). Under the terms and subject to the conditions of the Equity Line of Credit, the Company has the right, but not the obligation, to sell to Lincoln Park, and Lincoln Park is obligated to purchase, up to $35.0 million worth of shares of the Company’s common stock. The Company’s board of directors reserved 392,104 shares for issuance pursuant to the Equity Line of Credit (inclusive of commitment shares). On October 20, 2017, the Company issued 11,375 shares of its common stock, as initial commitment shares, to Lincoln Park with a fair value of $15.30 which was recorded as deferred financing costs and is included within other current assets in the accompanying balance sheet as of June 30, 2018. The deferred financing costs are amortized as interest expense using the effective interest rate method over the term of the Equity Line of Credit as there is no guaranty that additional shares will be sold under the Equity Line of Credit. Additionally, the Company will issue, pro rata, up to an additional 11,375 shares of its common stock as additional commitment shares to Lincoln Park in connection with any additional purchases. Such future sales of common stock by the Company, if any, will be subject to certain limitations, and may occur from time to time, at the Company’s option, over the 30-month period Public Offering – March 2017 On March 22, 2017, the Company completed a registered public offering of 977,500 shares of common stock at a price of $30.00 per share, which included the exercise in full by the underwriters of their over-allotment option to purchase up to 127,500 additional shares of common stock. The total proceeds from the offering were $26.6 million, net of underwriter’s discounts and commissions and offering expenses. Public Offering – April 2018 On April 3, 2018, the Company closed a public offering of 10,000,000 shares of common stock at a public offering price of $5.00 per share. We received gross proceeds of $50.0 million and approximately $45.6 million of net proceeds from this offering. The offering was made by the Company pursuant to a registration statement on Form S-1 Warrants Below is a table summarizing the warrants issued and outstanding for each of the periods presented: Warrants Outstanding as of As of December 31, 2017 Warrants Exercised Warrants Expired Warrants Outstanding As of June 30, 2018 Exercise Price Expiration Date 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 Total 199,524 — — 199,524 As of June 30, 2018, the Company had 199,524 warrants outstanding classified as equity warrants. Each warrant grants the holder the right to purchase one share of common stock. Equity warrants are recorded at their relative fair market value in the stockholders’ equity section of the balance sheet. The Company’s equity warrants can only be settled through the issuance of shares and do not have any anti-dilution or price reset provisions.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	8. Stock-Based Compensation The Amended and Restated 2014 Equity and Incentive Plan The Amended and Restated 2014 Equity and Incentive Plan (the “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 non-employee The following table summarizes option and award activity, excluding inducement grants, for the six months ended June 30, 2018 (unaudited): Weighted- Weighted- Average Average Remaining Shares Outstanding Exercise Contractual Aggregate Available for Number Price per Term Intrinsic Grant of Shares Share (In Years) Value Balance at December 31, 2017 29,571 99,029 $ 25.33 Additional shares reserved 1,225,223 — $ — Options granted (1,079,700 ) 1,079,700 $ 4.28 Options cancelled/forfeited/expired 6,248 (6,248 ) $ 23.03 Shares expired under 2012 Plan (1,867 ) — $ — Balance at June 30, 2018 179,475 1,172,481 $ 5.96 9.67 $ — Exercisable at June 30, 2018 81,371 $ 18.34 8.73 $ — Vested or expected to vest at June 30, 2018 1,060,324 $ 6.09 9.66 $ — 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 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 activities: Weighted- Remaining Outstanding Average Contractual Aggregate Number Exercise Term Intrinsic of Shares Price per Share (In Years) Value Balance at December 31, 2017 19,350 $ 19.12 Options granted — $ — Options cancelled/forfeited/expired (5,513 ) $ 15.40 Balance at June 30, 2018 13,837 $ 20.60 5.02 $ — Exercisable at June 30, 2018 9,165 $ 17.78 3.07 $ — Vested or expected to vest at June 30, 2018 13,430 $ 20.43 4.91 $ — The following summarizes the composition of stock options outstanding and exercisable within the approved stock options plans, which excludes inducement grants, as of June 30, 2018: Options Outstanding Options Exercisable Weighted- Average Weighted Weighted Remaining Average Average Number of Contractual Exercise Number of Exercise Exercise Price Shares Life (in years) Price Shares Price $4.24 - $4.24 946,064 9.79 $ 4.24 39,504 $ 4.24 $4.24 - $146.60 224,767 9.21 $ 11.87 40,587 $ 26.79 $181.00 - $181.00 100 6.81 $ 181.00 83 $ 181.00 $182.60 - $182.60 150 6.82 $ 182.60 118 $ 182.60 $185.80 - $185.80 1,400 6.89 $ 185.80 1,079 $ 185.80 Stock-Based Compensation Expense Total stock-based compensation expense recognized was as follows: Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 (unaudited; in thousands) (unaudited; in thousands) Research and development $ 142 $ 76 $ 209 $ 137 General and administrative 188 107 260 279 $ 330 $ 183 $ 469 $ 416 As of June 30, 2018, the Company had $3.8 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 3.7 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. The expected volatility is based on the historical stock volatilities of several of the Company’s publicly listed peers over a period equal to the expected terms of the options as the Company does not have sufficient trading history to use the volatility of its own common stock. 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 The following table presents the weighted-average assumptions for the Black-Scholes option-pricing model used in determining the fair value of options granted: For the three months ended June 30, For the six months ended June 30, 2018 2017 2018 2017 Dividend yield 0% 0% 0% 0% Risk-free interest rate 2.74% - 3.11% 1.90% 2.74% - 3.11% 1.90% - 2.13% Expected volatility 89% 89% 89% 89% Expected term (years) 6.08 6.08 6.08 6.08

Organization and Basis of Pre14

Organization and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	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 S-X. Form 10-K On January 23, 2018, the Company’s stockholders approved an increase to the number of authorized shares of the Company’s common stock from 100,000,000 to 250,000,000 shares. On January 23, 2018, the board of directors approved a 1-for-20 (pre-split)
Liquidity	Liquidity As of June 30, 2018, the Company has an accumulated deficit of $242.9 million, as well as recurring operating losses and negative cash flows from operating activities. Cash and cash equivalents at June 30, 2018 were approximately $16.2 million and short-term investments of $21.4 million. On April 3, 2018, the Company closed a public offering of 10,000,000 shares of common stock at a public offering price of $5.00 per share. The Company received gross proceeds of $50.0 million and approximately $45.6 million of net proceeds from the offering and plans to use the net proceeds from the offering to complete the long-term safety study of M207, and for working capital and general corporate purposes. The Company believes the completion of the public offering will allow it to continue executing on the timely filing of its NDA for M207, which it expects will occur in the fourth quarter of 2019. We expect cash and cash equivalents and investments will be sufficient to enable us to fund our anticipated level of operations based on our current operating plans beyond twelve months following the date of issuance of this Quarterly Report on From 10-Q. The Company has financed its operations through the sale of equity securities and debt financing. To date, none of the Company’s product candidates have been approved by the United States Food and Drug Administration for sale. The Company will continue to require additional financing to develop its product candidate, develop additional product candidates and fund operating losses. Management intends to seek capital to support the Company’s initiatives through financing activities such as public or private offerings of its common stock, and/or preferred stock offerings, issuances of debt and convertible debt instruments and collaborative or other arrangements with corporate partners. However, if such financing is not available at adequate levels or on acceptable terms, the Company could be required to significantly reduce its operating expenses and delay, reduce the scope of or eliminate some of its development programs, out-license The Company will continue to evaluate its timelines, strategic needs, and balance sheet 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, or achieve or sustain profitability in the future.
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.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash Equivalents and Restricted Cash The following table provides a reconciliation of cash, cash equivalents and restricted cash to amounts shown in the statement of cash flows in thousand: June 30, 2018 2017 Cash and cash equivalents $ 16,197 $ 21,159 Restricted cash 35 35 $ 16,232 $ 21,194
Restricted Cash	Restricted Cash The Company’s restricted cash consists of funds set aside by a contractual pledge and security agreement with a bank whereby $35,000 is held as a security for corporate purchasing cards.
Marketable Securities	Marketable Securities The Company classifies its investments in marketable securities as available-for available-for-sale
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 1: Inputs which include quoted prices in active markets for identical assets and liabilities. • Level 2: 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 3: 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, accounts receivable, and accounts payable, approximate fair value due to their relatively short maturities. The carrying value of the Company’s short-term notes payable approximates their fair value as the terms of the borrowing are consistent with current market rates and the duration to maturity is short.
Revenue	Revenue Effective January 1, 2018, the Company adopted Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers. In accordance with ASC Topic 606, the Company recognizes revenue when the customer obtains control of promised goods or services, in an amount that reflects the consideration which it expects to receive in exchange for those goods and services. To determine revenue recognition for arrangements that the Company deems are within the scope of ASC Topic 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) calculate transfer price; (iv) allocate the transaction price to the performance obligation in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation.
Deferred Revenue	Deferred Revenue Deferred revenue consists of amounts related to fees resulting from feasibility research projects received prior to satisfying the revenue recognition criteria (see, Revenue) and are recognized as deferred revenue in our balance sheet. Amounts are recognized as revenue upon satisfaction of the performance obligation as prescribed under ASC Topic 606.
Research and Development Expenses	Research and Development Expenses Research and development costs are charged to expense as incurred and consist of costs related to (i) furthering the Company’s research and development efforts, and (ii) designing and manufacturing products that incorporate the Company’s ADAM technology for the Company’s clinical and nonclinical studies.
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 common stock equivalents. Diluted earnings per common share is computed by giving effect to all potentially dilutive common stock equivalents outstanding for the period. For purposes of this calculation, warrants and options to purchase common stock are considered potentially dilutive common stock equivalents. For the six months ended June 30, 2018 and 2017, diluted net loss per common share was the same as basic net loss per common share since the effect of inclusion of potentially dilutive common stock equivalents would have an antidilutive effect due to the loss reported. 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: June 30, 2018 2017 Warrants to purchase common stock 199,524 347,311 Options to purchase common stock 1,186,318 109,173 1,385,842 456,484
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2018, the FASB issued ASU No. 2018-07, Compensation – Stock Compensation (Topic 718); Improvements to Nonemployee Share-Based Payment Accounting In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815), (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. 2016-13 2016-13 In February 2016, the FASB issued ASU 2016-02, Leases right-of-use

Summary of Significant Accoun15

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Reconciliation of Cash and Cash Equivalents, and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash to amounts shown in the statement of cash flows in thousand: June 30, 2018 2017 Cash and cash equivalents $ 16,197 $ 21,159 Restricted cash 35 35 $ 16,232 $ 21,194
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: June 30, 2018 2017 Warrants to purchase common stock 199,524 347,311 Options to purchase common stock 1,186,318 109,173 1,385,842 456,484

Cash, Cash Equivalents and In16

Cash, Cash Equivalents and Investments in Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2018
Cash and Cash Equivalents [Abstract]
Summary of Cash Equivalents and Investments Carried at Fair Value	The following table presents cash equivalents and investments carried at fair value in accordance with the fair value hierarchy defined in Note 2. Fair Value Measurements Quoted prices in active market Level I Significant other observable inputs Level II Significant unobservable inputs Level III (unaudited; in thousands) As of June 30, 2018: Cash and restricted cash, included in cash equivalents (1) $ 1,893 Total Money market funds, included in cash equivalents 5,109 5,109 — — Commercial paper, included in cash equivalents 5,733 — 5,733 — U.S. treasuries, included in cash equivalents 1,000 1,000 — — U.S. government agencies, included in cash equivalents 2,497 — 2,497 — Commercial paper 5,205 — 5,205 — Corporate notes and bonds 6,482 — 6,482 — U.S. treasuries 9,754 9,754 — — Total $ 35,780 $ 15,863 $ 19,917 — As of December 31, 2017: Cash and restricted cash, included in cash equivalents (1) $ 4,587 Total Money market funds, included in cash equivalents 6,414 6,414 — — U.S. government agencies, included in cash equivalents 650 — 650 — Total $ 7,064 $ 6,414 $ 650 — (1) Not subject to leveling
Summary of Investment Available for Sale	As of June 30, 2018 and December 31, 2017 available-for-sale June 30, 2018 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (unaudited; in thousands) Commercial paper $ 10,943 — (5 ) $ 10,938 Corporate notes and bonds 6,489 — (7 ) 6,482 U.S. Treasuries 10,756 — (2 ) 10,754 U.S. Government agencies 2,497 — — 2,497 $ 30,685 $ — $ (14 ) $ 30,671 December 31, 2017 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) U.S. government agency bonds $ 650 — — $ 650 $ 650 $ — $ — $ 650

Property and Equipment (Tables)

Property and Equipment (Tables)	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	The following summarizes the Company’s property and equipment for each of the periods presented: June 30, 2018 December 31, 2017 (unaudited; in thousands) Laboratory and office equipment $ 1,343 $ 1,159 Manufacturing equipment 10,423 10,387 Computer equipment and software 223 209 Leasehold improvements 16,460 15,660 Construction in progress 3,637 2,351 32,086 29,766 Less: accumulated depreciation (25,954 ) (25,614 ) $ 6,132 $ 4,152

Debt Financing (Tables)

Debt Financing (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Summary of Debt, Net of Unamortized Debt Discount and Issuance Costs	The following is a summary of the Company’s debt, net of unamortized debt discount and issuance costs for the periods presented: June 30, December 31, 2018 2017 (unaudited; in thousands) Principal amount $ 3,233 $ 6,316 Less: unamortized debt issuance costs (2 ) (10 ) unamortized fair value of free standing warrant (4 ) (18 ) Plus: unamortized fair value debt premium 8 35 accrued terminal interest 344 320 accrued interest 21 44 Secured promissory note, net of unamortized debt issuance cost and premium, current $ 3,600 $ 6,687

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Payments under Non-Cancellable Related Party Operating Lease	As of June 30, 2018, future minimum payments under the Company’s non-cancelable Total (unaudited; in thousands) Remaining of 2018 $ 833 2019 1,754 2020 1,807 2021 1,861 2022 1,914 2023 and thereafter 3,310 $ 11,479

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2018
Federal Home Loan Banks [Abstract]
Summary of Warrants Issued and Outstanding	Below is a table summarizing the warrants issued and outstanding for each of the periods presented: Warrants Outstanding as of As of December 31, 2017 Warrants Exercised Warrants Expired Warrants Outstanding As of June 30, 2018 Exercise Price Expiration Date 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 Total 199,524 — — 199,524

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2018
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 six months ended June 30, 2018 (unaudited): Weighted- Weighted- Average Average Remaining Shares Outstanding Exercise Contractual Aggregate Available for Number Price per Term Intrinsic Grant of Shares Share (In Years) Value Balance at December 31, 2017 29,571 99,029 $ 25.33 Additional shares reserved 1,225,223 — $ — Options granted (1,079,700 ) 1,079,700 $ 4.28 Options cancelled/forfeited/expired 6,248 (6,248 ) $ 23.03 Shares expired under 2012 Plan (1,867 ) — $ — Balance at June 30, 2018 179,475 1,172,481 $ 5.96 9.67 $ — Exercisable at June 30, 2018 81,371 $ 18.34 8.73 $ — Vested or expected to vest at June 30, 2018 1,060,324 $ 6.09 9.66 $ —
Summary of Company's Inducement Grant Stock Option Activities	The following table summarizes the Company’s inducement grant stock option activities: Weighted- Remaining Outstanding Average Contractual Aggregate Number Exercise Term Intrinsic of Shares Price per Share (In Years) Value Balance at December 31, 2017 19,350 $ 19.12 Options granted — $ — Options cancelled/forfeited/expired (5,513 ) $ 15.40 Balance at June 30, 2018 13,837 $ 20.60 5.02 $ — Exercisable at June 30, 2018 9,165 $ 17.78 3.07 $ — Vested or expected to vest at June 30, 2018 13,430 $ 20.43 4.91 $ —
Summary of Stock Options Outstanding and Exercisable within the Approved Stock Options Plans, Excludes Inducement Grants	The following summarizes the composition of stock options outstanding and exercisable within the approved stock options plans, which excludes inducement grants, as of June 30, 2018: Options Outstanding Options Exercisable Weighted- Average Weighted Weighted Remaining Average Average Number of Contractual Exercise Number of Exercise Exercise Price Shares Life (in years) Price Shares Price $4.24 - $4.24 946,064 9.79 $ 4.24 39,504 $ 4.24 $4.24 - $146.60 224,767 9.21 $ 11.87 40,587 $ 26.79 $181.00 - $181.00 100 6.81 $ 181.00 83 $ 181.00 $182.60 - $182.60 150 6.82 $ 182.60 118 $ 182.60 $185.80 - $185.80 1,400 6.89 $ 185.80 1,079 $ 185.80
Summary of Stock-Based Compensation Expense	Total stock-based compensation expense recognized was as follows: Three months ended June 30, Six months ended June 30, 2018 2017 2018 2017 (unaudited; in thousands) (unaudited; in thousands) Research and development $ 142 $ 76 $ 209 $ 137 General and administrative 188 107 260 279 $ 330 $ 183 $ 469 $ 416
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: For the three months ended June 30, For the six months ended June 30, 2018 2017 2018 2017 Dividend yield 0% 0% 0% 0% Risk-free interest rate 2.74% - 3.11% 1.90% 2.74% - 3.11% 1.90% - 2.13% Expected volatility 89% 89% 89% 89% Expected term (years) 6.08 6.08 6.08 6.08

Organization and Basis of Pre22

Organization and Basis of Presentation - Additional Information (Detail) $ / shares in Units, $ in Thousands	Apr. 03, 2018USD ($)$ / sharesshares	Jan. 25, 2018shares	Jan. 23, 2018$ / sharesshares	Jan. 22, 2018$ / sharesshares	Mar. 22, 2017$ / sharesshares	Mar. 31, 2018USD ($)	Jun. 30, 2018USD ($)$ / sharesshares	Jun. 30, 2017USD ($)	Jan. 24, 2018shares	Dec. 31, 2017USD ($)$ / sharesshares
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Common stock shares authorized | shares		250,000,000	250,000,000	100,000,000			250,000,000		100,000,000	100,000,000
Stockholders equity reverse stock split			1-for-20				1-for-20
Stock split ratio		0.05	0.05
Common stock par value | $ / shares			$ 0.0001	$ 0.0001			$ 0.0001			$ 0.0001
Common shares outstanding change due to split | shares			1,973,039	39,460,931
Accumulated deficit							$ (242,916)			$ (225,874)
Cash and cash equivalents							16,197	$ 21,159		11,651
Common stock shares issued | shares	10,000,000				977,500
Offering price per share | $ / shares	$ 5				$ 30
Gross proceeds from issuance of stock	$ 50,000
Proceeds from issuance of stock	$ 45,600					$ 26,600	45,603	$ 26,623
Short-term investments							$ 21,441			$ 0

Summary of Significant Accoun23

Summary of Significant Accounting Policies - Summary of Reconciliation of Cash and Cash Equivalents, and Restricted Cash (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 16,197	$ 11,651	$ 21,159
Restricted cash	35		35
Total	$ 16,232	$ 11,686	$ 21,194	$ 15,038

Summary of Significant Accoun24

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	Jun. 30, 2018USD ($)
Regulatory Assets [Abstract]
Restricted cash	$ 35,000

Summary of Significant Accoun25

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	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock excluded from computation of diluted net loss per share	1,385,842	456,484
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock excluded from computation of diluted net loss per share	199,524	347,311
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Common stock excluded from computation of diluted net loss per share	1,186,318	109,173

Cash, Cash Equivalents and In26

Cash, Cash Equivalents and Investments in Marketable Securities - Summary of Cash Equivalents and Investments Carried at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Cash and restricted cash, included in cash equivalents	$ 16,232	$ 11,686	$ 21,194	$ 15,038
Available for sale securities	30,671	650
Commercial Paper [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	10,938
Corporate Notes and Bonds [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	6,482
U.S Treasuries [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	10,754
Estimate of Fair Value Measurement [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Cash and restricted cash, included in cash equivalents	1,893	4,587
Available for sale securities	35,780	7,064
Estimate of Fair Value Measurement [Member] | Money Market Funds Included In Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	5,109	6,414
Estimate of Fair Value Measurement [Member] | Commercial Paper Included In Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	5,733
Estimate of Fair Value Measurement [Member] | US Treasury Securities Included in Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	1,000
Estimate of Fair Value Measurement [Member] | US Government Agencies Debt Securities Included in Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	2,497	650
Estimate of Fair Value Measurement [Member] | Commercial Paper [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	5,205
Estimate of Fair Value Measurement [Member] | Corporate Notes and Bonds [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	6,482
Estimate of Fair Value Measurement [Member] | U.S Treasuries [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	9,754
Estimate of Fair Value Measurement [Member] | Level I [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	15,863	6,414
Estimate of Fair Value Measurement [Member] | Level I [Member] | Money Market Funds Included In Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	5,109	6,414
Estimate of Fair Value Measurement [Member] | Level I [Member] | Commercial Paper Included In Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level I [Member] | US Treasury Securities Included in Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	1,000
Estimate of Fair Value Measurement [Member] | Level I [Member] | US Government Agencies Debt Securities Included in Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0	0
Estimate of Fair Value Measurement [Member] | Level I [Member] | Commercial Paper [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level I [Member] | Corporate Notes and Bonds [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level I [Member] | U.S Treasuries [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	9,754
Estimate of Fair Value Measurement [Member] | Level II [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	19,917	650
Estimate of Fair Value Measurement [Member] | Level II [Member] | Money Market Funds Included In Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0	0
Estimate of Fair Value Measurement [Member] | Level II [Member] | Commercial Paper Included In Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	5,733
Estimate of Fair Value Measurement [Member] | Level II [Member] | US Treasury Securities Included in Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level II [Member] | US Government Agencies Debt Securities Included in Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	2,497	650
Estimate of Fair Value Measurement [Member] | Level II [Member] | Commercial Paper [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	5,205
Estimate of Fair Value Measurement [Member] | Level II [Member] | Corporate Notes and Bonds [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	6,482
Estimate of Fair Value Measurement [Member] | Level II [Member] | U.S Treasuries [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level III [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0	0
Estimate of Fair Value Measurement [Member] | Level III [Member] | Money Market Funds Included In Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0	0
Estimate of Fair Value Measurement [Member] | Level III [Member] | Commercial Paper Included In Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level III [Member] | US Treasury Securities Included in Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level III [Member] | US Government Agencies Debt Securities Included in Cash Equivalents [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0	$ 0
Estimate of Fair Value Measurement [Member] | Level III [Member] | Commercial Paper [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level III [Member] | Corporate Notes and Bonds [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	0
Estimate of Fair Value Measurement [Member] | Level III [Member] | U.S Treasuries [Member]
Schedule Of Cash Equivalents And Available For Sale Investments [Line Items]
Available for sale securities	$ 0

Cash, Cash Equivalents and In27

Cash, Cash Equivalents and Investments in Marketable Securities - Summary of Investment Available for Sale (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Cost	$ 30,685	$ 650
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(14)	0
Estimated Fair Value	30,671	650
Commercial Paper [Member]
Debt Securities, Available-for-sale [Line Items]
Cost	10,943
Gross Unrealized Gains	0
Gross Unrealized Losses	(5)
Estimated Fair Value	10,938
Corporate Notes and Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Cost	6,489
Gross Unrealized Gains	0
Gross Unrealized Losses	(7)
Estimated Fair Value	6,482
U.S Treasuries [Member]
Debt Securities, Available-for-sale [Line Items]
Cost	10,756
Gross Unrealized Gains	0
Gross Unrealized Losses	(2)
Estimated Fair Value	10,754
U.S Government Agency Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Cost	2,497	650
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	$ 2,497	$ 650

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 32,086	$ 29,766
Less: accumulated depreciation	(25,954)	(25,614)
Property and equipment, net	6,132	4,152
Laboratory and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,343	1,159
Manufacturing Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	10,423	10,387
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	223	209
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	16,460	15,660
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,637	$ 2,351

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 200	$ 600	$ 391	$ 1,261

Debt Financing - Additional Inf

Debt Financing - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Jun. 01, 2017
Debt Instrument [Line Items]
Interest expense		$ 100,000	$ 200,000	$ 300,000	$ 500,000
Senior Secured Term Loan with Hercules [Member]
Debt Instrument [Line Items]
Debt interest rate						7.95%
Senior Subordinated Notes [Member] | Senior Secured Term Loan with Hercules [Member]
Debt Instrument [Line Items]
Debt payment terms				Equal installment payments of principal and interest are due monthly, with all outstanding amounts due and payable on December 1, 2018.
Debt face amount		15,000,000		$ 15,000,000
Debt payment, due and payable date				Dec. 1, 2018
Debt effective interest rate	7.95%
Debt variable interest rate	7.95%
Debt additional variable interest rate decrease	5.25%
Debt end of term charge							$ 100,000
Debt prepayment penalty description				The Company may prepay all, but not less than all, of the Hercules Term Loan with no prepayment charge.
Additional debt end of term charge		$ 351,135		$ 351,135
Debt interest rate		7.95%		7.95%
Senior Subordinated Notes [Member] | Senior Secured Term Loan with Hercules [Member] | After June 23, 2017 [Member]
Debt Instrument [Line Items]
Prepayment penalty charge on outstanding principal after lock-in period	$ 0

Debt Financing - Summary of Deb

Debt Financing - Summary of Debt, Net of Unamortized Debt Discount and Issuance Costs (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt
Principal amount	$ 3,233	$ 6,316
Less: unamortized debt issuance costs	(2)	(10)
unamortized fair value of free standing warrant	(4)	(18)
Plus: unamortized fair value debt premium	8	35
accrued terminal interest	344	320
accrued interest	21	44
Secured promissory note, net of unamortized debt issuance cost and premium, current	$ 3,600	$ 6,687

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	May 10, 2018	Jun. 06, 2017	May 08, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other Commitments [Line Items]
Purchase commitments related to fixed assets						$ 12,200,000
Chief Executive Officer [Member] | Employee Severance [Member]
Other Commitments [Line Items]
Severance cost			$ 252,000
Term of base salary and benefit continuation coverage on separation agreement			6 months
Chief Financial Officer [Member] | Employee Severance [Member]
Other Commitments [Line Items]
Severance cost	$ 201,000
Term of base salary and benefit continuation coverage on separation agreement						6 months
Accrued and unpaid severance cost						$ 152,000
Percentage of unvested portion of equity awards at time of resignation						25.00%
Seventh Amendment to Lease Agreement [Member]
Other Commitments [Line Items]
Operating lease amendment description						Under the Seventh Amendment, the Company extended the term of the lease for the Company’s headquarters in Fremont, California through August 31, 2024, with an option to further extend the lease for an additional 65 months, subject to certain terms and conditions. The Company has agreed to pay a monthly base rent of $136,191 for the period commencing September 1, 2017, and ending on August 31, 2018, with an increase on September 1, 2018, and annual increases on September 1 of each subsequent year until the lease year beginning September 1, 2023. The Seventh Amendment also provides for rent abatements, subject to certain conditions, totaling $275,552 and certain tenant improvements to be completed at the Landlord’s expense (not to exceed $975,000 or, under certain conditions, $1,100,000). The Company will incur additional expense of approximately $0.4 million under the lease in connection with roof repairs that will be treated as additional rent and paid over the term of the lease.
Extended lease term		65 months
Monthly base rent payable		$ 136,191
Rent abatements		275,552
Tenant improvements		975,000
Tenant improvements under certain conditions		1,100,000
Additional expense incurred under operating lease		$ 400,000
Eight Amendment [Member]
Other Commitments [Line Items]
Rental expense				$ 400,000	$ 200,000	$ 800,000	$ 400,000

Commitments and Contingencies33

Commitments and Contingencies - Schedule of Future Minimum Payments under Non-Cancellable Related Party Operating Lease (Detail) $ in Thousands	Jun. 30, 2018USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Operating lease future minimum payments due, remaining of 2018	$ 833
Operating lease future minimum payments due, 2019	1,754
Operating lease future minimum payments due, 2020	1,807
Operating lease future minimum payments due, 2021	1,861
Operating lease future minimum payments due, 2022	1,914
2023 and thereafter	3,310
Operating lease future minimum payments due	$ 11,479

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Thousands	Apr. 03, 2018USD ($)$ / sharesshares	Jan. 25, 2018shares	Jan. 23, 2018shares	Oct. 20, 2017USD ($)$ / sharesshares	Mar. 22, 2017$ / sharesshares	Mar. 31, 2018USD ($)shares	Jun. 30, 2018USD ($)shares	Jun. 30, 2017USD ($)	Jan. 24, 2018shares	Jan. 22, 2018shares	Dec. 31, 2017shares
Class of Stock [Line Items]
Common stock, shares authorized		250,000,000	250,000,000				250,000,000		100,000,000	100,000,000	100,000,000
Reverse stock split, conversion ratio		0.05	0.05
Reverse stock split description			1-for-20				1-for-20
Common stock shares issued	10,000,000				977,500
Offering price per share | $ / shares	$ 5				$ 30
Proceeds from issuance of stock | $	$ 45,600					$ 26,600	$ 45,603	$ 26,623
Gross proceeds from issuance of stock | $	$ 50,000
Equity warrants outstanding							199,524				199,524
Number of securities called by each warrant							1
Lincoln Park Capital Fund Llc [Member]
Class of Stock [Line Items]
Common stock shares issued							0
Over-Allotment [Member]
Class of Stock [Line Items]
Common stock shares issued						127,500
Equity Lines of Credit [Member] | Lincoln Park Capital Fund Llc [Member]
Class of Stock [Line Items]
Number of shares obligated to purchase | $				$ 35,000
Common stock shares issued				11,375
Fair value of share | $ / shares				$ 15.30
Additional shares committed to issue				11,375
Equity Lines of Credit [Member] | Director [Member] | Lincoln Park Capital Fund Llc [Member]
Class of Stock [Line Items]
Shares reserved for future issuance				392,104

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Warrants Issued and Outstanding (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	199,524	199,524
Hercules - June 2014 [Member]
Class of Warrant or Right [Line Items]
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	1,583	1,583
Exercise Price	$ 176.80
Expiration Date	Jan. 27, 2020
Hercules - June 2015 [Member]
Class of Warrant or Right [Line Items]
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	2,035	2,035
Exercise Price	$ 147.40
Expiration Date	Jun. 23, 2020
Private Investment in Public Equity (PIPE) [Member] | Series B [Member]
Class of Warrant or Right [Line Items]
Warrants Exercised	0
Warrants Expired	0
Warrants Outstanding	195,906	195,906
Exercise Price	$ 31
Expiration Date	Aug. 19, 2021

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant	179,475	29,571
Stock option awards granted	1,079,700
Unrecognized stock-based compensation expense	$ 3.8
Weighted-average period of unrecognized stock-based compensation expense	3 years 8 months 12 days
New Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Vesting term	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.
Non Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option awards granted	131,000
Amended and Restated 2014 Equity and Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	1,348,173
Options vested period	4 years
Shares available for grant	179,475
Amended and Restated 2014 Equity and Incentive Plan [Member] | Maximum [Member]
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) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Aggregate Intrinsic Value, Exercisable | $	$ 0
Aggregate Intrinsic Value, Vested or expected to vest | $	$ 0
Shares Available for Grant, Beginning balance	29,571
Shares Available for Grant, Options reserved	1,225,223
Shares Available for Grant, Options granted	(1,079,700)
Shares Available for Grant, Options cancelled/forfeited/expired	6,248
Shares Available for Grant, Shares expired under 2012 Plan	(1,867)
Shares Available for Grant, Ending balance	179,475
Outstanding Number of Shares, Beginning balance	99,029
Outstanding Number of Shares, Options granted	1,079,700
Outstanding Number of Shares, Options cancelled/forfeited/expired	(6,248)
Outstanding Number of Shares, Ending balance	1,172,481
Outstanding Number of Shares, Exercisable	81,371
Outstanding Number of Shares, Restricted stock vested and released	1,060,324
Weighted-Average Exercise Price per Share, beginning balance | $ / shares	$ 25.33
Weighted-Average Exercise Price per Share, Options granted | $ / shares	4.28
Weighted-Average Exercise Price per Share, Options cancelled/forfeited/expired | $ / shares	23.03
Weighted-Average Exercise Price per Share, Ending balance | $ / shares	5.96
Weighted-Average Exercise Price per Share, Exercisable | $ / shares	18.34
Weighted-Average Exercise Price per Share, Vested or expected to vest | $ / shares	$ 6.09
Average Remaining Contractual Term	9 years 8 months 2 days
Average Remaining Contractual Term, Exercisable	8 years 8 months 23 days
Average Remaining Contractual Term, Vested or expected to vest	9 years 7 months 28 days

Stock-Based Compensation - Su38

Stock-Based Compensation - Summary of Company's Inducement Grant Stock Option Activities (Detail) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Number of Shares, Beginning balance | shares	99,029
Outstanding Number of Shares, Options granted | shares	1,079,700
Shares Available for Grant, Options cancelled/forfeited/expired | shares	6,248
Outstanding Number of Shares, Ending balance | shares	1,172,481
Outstanding Number of Shares, Exercisable | shares	81,371
Outstanding Number of Shares, Restricted stock vested and released | shares	1,060,324
Weighted-Average Exercise Price per Share, beginning balance | $ / shares	$ 25.33
Weighted-Average Exercise Price per Share, Options granted | $ / shares	4.28
Weighted-Average Exercise Price per Share, Options cancelled/forfeited/expired | $ / shares	23.03
Weighted-Average Exercise Price per Share, Ending balance | $ / shares	5.96
Weighted-Average Exercise Price per Share, Exercisable | $ / shares	18.34
Weighted-Average Exercise Price per Share, Vested or expected to vest | $ / shares	$ 6.09
Remaining Contractual Term	9 years 8 months 2 days
Remaining Contractual Term, Exercisable	8 years 8 months 23 days
Remaining Contractual Term, Vested or expected to vest	9 years 7 months 28 days
Aggregate Intrinsic Value, Exercisable | $	$ 0
Aggregate Intrinsic Value, Vested or expected to vest | $	$ 0
Inducement Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Number of Shares, Beginning balance | shares	19,350
Outstanding Number of Shares, Options granted | shares	0
Shares Available for Grant, Options cancelled/forfeited/expired | shares	(5,513)
Outstanding Number of Shares, Ending balance | shares	13,837
Outstanding Number of Shares, Exercisable | shares	9,165
Outstanding Number of Shares, Restricted stock vested and released | shares	13,430
Weighted-Average Exercise Price per Share, beginning balance | $ / shares	$ 19.12
Weighted-Average Exercise Price per Share, Options granted | $ / shares	0
Weighted-Average Exercise Price per Share, Options cancelled/forfeited/expired | $ / shares	15.40
Weighted-Average Exercise Price per Share, Ending balance | $ / shares	20.60
Weighted-Average Exercise Price per Share, Exercisable | $ / shares	17.78
Weighted-Average Exercise Price per Share, Vested or expected to vest | $ / shares	$ 20.43
Remaining Contractual Term	5 years 7 days
Remaining Contractual Term, Exercisable	3 years 26 days
Remaining Contractual Term, Vested or expected to vest	4 years 10 months 28 days
Aggregate Intrinsic Value, Outstanding | $	$ 0
Aggregate Intrinsic Value, Exercisable | $	0
Aggregate Intrinsic Value, Vested or expected to vest | $	$ 0

Stock-Based Compensation - Su39

Stock-Based Compensation - Summary of Stock Options Outstanding and Exercisable within the Approved Stock Options Plans, Excludes Inducement Grants (Detail) - 2012 and 2014 Plan Excluding Inducement Grants [Member]	6 Months Ended
	Jun. 30, 2018$ / sharesshares
$4.24 - $4.24 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price, Minimum	$ 4.24
Options Outstanding, Exercise Price, Maximum	$ 4.24
Options Outstanding, Number of Shares | shares	946,064
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	9 years 9 months 14 days
Options Outstanding, Weighted Average Exercise Price	$ 4.24
Options Exercisable, Number of Shares | shares	39,504
Options Exercisable,Weighted Average Exercise Price	$ 4.24
$4.24 - $146.60 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price, Minimum	4.24
Options Outstanding, Exercise Price, Maximum	$ 146.60
Options Outstanding, Number of Shares | shares	224,767
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	9 years 2 months 16 days
Options Outstanding, Weighted Average Exercise Price	$ 11.87
Options Exercisable, Number of Shares | shares	40,587
Options Exercisable,Weighted Average Exercise Price	$ 26.79
$181.00 - $181.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price, Minimum	181
Options Outstanding, Exercise Price, Maximum	$ 181
Options Outstanding, Number of Shares | shares	100
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	6 years 9 months 22 days
Options Outstanding, Weighted Average Exercise Price	$ 181
Options Exercisable, Number of Shares | shares	83
Options Exercisable,Weighted Average Exercise Price	$ 181
$182.60 - $182.60 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price, Minimum	182.60
Options Outstanding, Exercise Price, Maximum	$ 182.60
Options Outstanding, Number of Shares | shares	150
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	6 years 9 months 25 days
Options Outstanding, Weighted Average Exercise Price	$ 182.60
Options Exercisable, Number of Shares | shares	118
Options Exercisable,Weighted Average Exercise Price	$ 182.60
$185.80 - $185.80 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price, Minimum	185.80
Options Outstanding, Exercise Price, Maximum	$ 185.80
Options Outstanding, Number of Shares | shares	1,400
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	6 years 10 months 21 days
Options Outstanding, Weighted Average Exercise Price	$ 185.80
Options Exercisable, Number of Shares | shares	1,079
Options Exercisable,Weighted Average Exercise Price	$ 185.80

Stock-Based Compensation - Su40

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 330	$ 183	$ 469	$ 416
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	142	76	209	137
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 188	$ 107	$ 260	$ 279

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Dividend yield	0.00%	0.00%	0.00%	0.00%
Risk-free interest rate		1.90%
Risk-free interest rate, minimum	2.74%		2.74%	1.90%
Risk-free interest rate, maximum	3.11%		3.11%	2.13%
Expected volatility	89.00%	89.00%	89.00%	89.00%
Expected term (years)	6 years 29 days	6 years 29 days	6 years 29 days	6 years 29 days