Achaogen (AKAOQ) 10-Q 7 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 02, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus (i.e. Q1,Q2,Q3,FY)	Q3
Trading Symbol	AKAO
Entity Registrant Name	Achaogen Inc
Entity Central Index Key	1,301,501
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		27,451,400

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 41,802	$ 20,287
Short-term investments	19,287	38,444
Contracts receivable	14,893	5,039
Prepaids and other current assets	3,246	1,719
Restricted cash	127	0
Total current assets	79,355	65,489
Property and equipment, net	1,006	905
Restricted cash	250	127
Deposit and other assets	53	342
Total assets	80,664	66,863
Current liabilities:
Accounts payable	7,606	3,537
Accrued liabilities	10,920	4,927
Loan payable, current	1,042	0
Other current liabilities	269	225
Total current liabilities	19,837	8,689
Loan payable, long-term	23,975	14,536
Warrant liability	5,422	0
Derivative liability	413	375
Other long-term liabilities	0	104
Total liabilities	49,647	23,704
Commitments and contingencies
Stockholders’ equity
Common stock, $0.001 par value, 290,000,000 shares authorized at September 30, 2016 and December 31, 2015; 27,451,400 and 18,395,219 shares issued and outstanding at September 30, 2016 and December 31, 2015, respectively	27	18
Preferred stock, $0.001 par value, 10,000,000 shares authorized and zero shares issued and outstanding at September 30, 2016 and December 31, 2015	0	0
Additional paid-in-capital	248,494	219,182
Accumulated deficit	(217,496)	(175,993)
Accumulated other comprehensive loss	(8)	(48)
Total stockholders’ equity	31,017	43,159
Total liabilities and stockholders’ equity	$ 80,664	$ 66,863

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Common stock, par value (dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	290,000,000	290,000,000
Common stock, shares issued	27,451,400	18,395,219
Common stock, shares outstanding	27,451,400	18,395,219
Preferred stock, par value (dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Contract revenue	$ 16,046	$ 4,476	$ 31,039	$ 21,397
Operating expenses
Research and development	20,536	10,000	56,137	27,967
General and administrative	4,460	3,006	12,188	9,119
Total operating expenses	24,996	13,006	68,325	37,086
Loss from operations	(8,950)	(8,530)	(37,286)	(15,689)
Interest expense	(670)	(264)	(1,555)	(264)
Change in warrant and derivative liabilities	(1,499)	0	(2,881)	0
Other income, net	81	32	219	126
Net loss	$ (11,038)	$ (8,762)	$ (41,503)	$ (15,827)
Basic and diluted net loss per common share (dollars per share)	$ (0.41)	$ (0.48)	$ (1.88)	$ (0.88)
Weighted-average common shares outstanding used to calculate basic and diluted net loss per common share (shares)	26,789,397	18,150,331	22,046,368	18,073,479

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (11,038)	$ (8,762)	$ (41,503)	$ (15,827)
Other comprehensive (loss) income:
Net unrealized gain (loss) on available-for-sale securities	(13)	4	40	32
Total comprehensive loss	$ (11,051)	$ (8,758)	$ (41,463)	$ (15,795)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net loss	$ (41,503)	$ (15,827)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	333	310
Amortization of premium on short-term investments	278	333
Stock-based compensation expense	2,726	2,286
Change in warrant and derivative liabilities	2,881	7
Non-cash interest expense relating to loan payable	481	171
Change in operating assets and liabilities:
Contracts receivable	(9,854)	1,330
Prepaids and other assets	(340)	(1,508)
Accounts payable and accrued liabilities	10,062	3,278
Other liabilities	(60)	9
Net cash used in operating activities	(34,996)	(9,611)
Cash flows from investing activities:
Purchase of property and equipment	(434)	(421)
Purchase of short-term investments	(19,311)	(31,503)
Maturities of short-term investments	38,230	40,624
Change in restricted cash	(250)	0
Net cash provided by investing activities	18,235	8,700
Cash flows from financing activities:
Proceeds from issuance of common stock and warrants, net of issuance costs	28,095	1,319
Proceeds from issuance of loan payable	10,000	14,590
Proceeds from issuance of common stock in conjunction with equity incentive plans	181	1,183
Net cash provided by financing activities	38,276	17,092
Net increase in cash and cash equivalents	21,515	16,181
Cash and cash equivalents, beginning of period	20,287	18,881
Cash and cash equivalents, end of period	41,802	35,062
Supplemental disclosures of cash flow information
Interest paid	1,074	0
Issuance of derivative in connection with issuance of loan payable	$ 0	$ 356

Organization and Basis of Prese

Organization and Basis of Presentation and Consolidation	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation and Consolidation	Organization and Basis of Presentation and Consolidation Achaogen, Inc. (together with its consolidated subsidiary, the "Company") is a clinical-stage biopharmaceutical company passionately committed to the discovery, development, and commercialization of novel antibacterial drugs to treat multi-drug resistant gram-negative infections. The Company is developing plazomicin, its lead product candidate, for the treatment of serious bacterial infections due to multi-drug resistant Enterobacteriaceae, including carbapenem-resistant Enterobacteriaceae ("CRE"). The Company’s Phase 3 study of plazomicin in the treatment of patients with complicated urinary tract infections ("cUTI") and acute pyelonephritis ("AP"), entitled EPIC (Evaluating Plazomicin In cUTI), is expected to serve as a single pivotal study supporting a new drug application ("NDA") for plazomicin in the United States. In addition, the Company's Phase 3 study of plazomicin, entitled CARE (Combating Antibiotic Resistant Enterobacteriaceae), which is a resistant pathogen-specific trial designed to evaluate the efficacy and safety of plazomicin in patients with certain infections due to CRE, is intended to provide important and meaningful supportive data to be submitted with the plazomicin NDA. The Company was incorporated in Delaware in 2002 and commenced operations in 2004. Since commencing operations in 2004, the Company has devoted substantially all of its resources to identifying and developing its product candidates, including conducting preclinical studies and clinical trials and providing general and administrative support for these operations. Basis of Presentation and Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and following the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the Company’s financial information. The results of operations for the three-month and nine-month periods ended September 30, 2016 are not necessarily indicative of the results to be expected for the full year or any other future period. The balance sheet as of December 31, 2015 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. Intercompany accounts and transactions have been eliminated upon consolidation. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2015 included in the Company’s Annual Report on Form 10-K. On June 3, 2016, the Company sold 7,999,996 shares of its common stock and warrants to purchase 1,999,999 shares of its common stock pursuant to Securities Purchase Agreement (the "Purchase Agreement") for aggregate gross proceeds of $25.4 million and aggregate net proceeds of $25.1 million , after deducting the issuance costs, in connection with a private placement financing transaction (the "Private Placement"). The warrants have an exercise price of $3.66 per share and are exercisable up to five years from the date of issuance. On April 7, 2015, the Company filed a Registration Statement on Form S-3, declared effective by the SEC on April 21, 2015, covering the offering of up to $150.0 million of common stock, preferred stock, debt securities, warrants, purchase contracts and/or units. This Registration Statement included a prospectus covering the offering, issuance and sale of up to $30.0 million of shares of our common stock from time to time in an "at-the-market" ("ATM") equity offering pursuant to a sales agreement with Cowen and Company, LLC. As of September 30, 2016, the Company had sold 1,105,549 shares pursuant to its ATM equity offering program at a weighted-average price of $4.82 per share for aggregate offering proceeds of $5.3 million and aggregate net proceeds of $5.1 million , after deducting the sales commissions and offering expenses. In March 2014, the Company completed its initial public offering (“IPO”) of shares of its common stock, pursuant to which the Company issued 6,900,000 shares of common stock, which includes 900,000 shares issued pursuant to the over-allotment option granted to its underwriters, and received net proceeds of approximately $73.9 million , after deducting underwriting discounts, commissions and offering expenses. In connection with the completion of the Company’s IPO, all shares of convertible preferred stock converted into 10,386,894 shares of common stock and all of the Company’s convertible preferred stock warrants were converted into warrants to purchase common stock. The Company has incurred losses and negative cash flows from operations every year since its inception. As of September 30, 2016, the Company had unrestricted cash, cash equivalents and short-term investments of approximately $61.1 million and an accumulated deficit of approximately $217.5 million . Management expects to continue to incur additional substantial losses for the foreseeable future as a result of the Company's research and development activities, and the amounts of unrestricted cash, cash equivalents and short-term investments held at September 30, 2016 are sufficient to fund our current planned operations at least through the beginning of the second quarter of 2017 without securing additional funding sources. Management is currently evaluating different options for the raising of additional funds through equity or debt financing arrangements, government contracts and/or third party collaboration funding, however, there can be no assurance that such funding sources will be available at terms acceptable to the Company or at all. If the Company is unable to raise additional funding to meet its working capital needs, it will be forced to delay or reduce the scope of its research programs and/or limit or cease its operations. The lack of financial resources to fund projected negative cash flows and the resultant need to raise substantial additional funding in the near term in order to sustain operations raise substantial doubt as to the Company's ability to continue as a going concern. The accompanying financial statements have been prepared assuming that the Company will continue as a going concern, which contemplates the realization of assets and the settlement of liabilities and commitments in the normal course of business. The financial statements do not reflect any adjustments relating to the recoverability and reclassification of assets and liabilities that might be necessary if the Company is unable to continue as a going concern.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The accompanying financial statements have been prepared in accordance with U.S. GAAP. The preparation of financial statements in conformity with U.S. GAAP requires management to make judgments, assumptions and estimates that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures of contingent liabilities. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of liabilities, common stock and stock-based awards and income taxes. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates. Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, including cash and cash equivalents, contracts receivable, prepaid and other current assets, accounts payable, accrued liabilities, and other current liabilities approximate fair value due to their short-term maturities. Short-term investments consist of available-for-sale securities and are carried at fair value. Based upon the borrowing rates (which is a Level 2 input) currently available to the Company for loans with similar terms, the Company believes the carrying amount of the loan payable approximates its fair value. The warrant and derivative liabilities are recorded at estimated fair value with changes in estimated fair value recorded in the Company's statements of operations. Cash and Cash Equivalents Cash equivalents include only securities having a maturity of three months or less at the time of purchase. As of September 30, 2016 and December 31, 2015, cash and cash equivalents consisted of bank deposits, cash, commercial paper and investments in money market funds. Short-term Investments Short-term investments consist of debt securities with maturities greater than three months, but less than one year from the date of acquisition, and are classified as available for sale. Short-term investments are carried at fair value. Unrealized gains and losses on available-for-sale securities are excluded from earnings and reported as a component of net unrealized gain (loss) on available-for-sale securities in the Company's consolidated statements of comprehensive loss. The amortized cost of debt securities reflects amortization of purchase premiums and accretion of purchase discounts to date, which are included in interest income. The Company reviews all of its marketable securities on a regular basis to evaluate whether any security has experienced an other-than-temporary decline in fair value. Restricted Cash At September 30, 2016 and December 31, 2015, the Company had restricted cash of $377,000 and $127,000 . The restricted cash, which consists of money market accounts with one of the Company’s financial institutions, serves as collateral for the letters of credit provided as security deposits under the Company’s facility leases. As of September 30, 2016, $127,000 of restricted cash is classified as current assets and relates to the current facility lease that expires on April 14, 2017 . Warrant Liability On June 3, 2016, the Company issued warrants to purchase 1,999,999 shares of its common stock in connection with the Private Placement. Each warrant has an exercise price of $3.66 per share and is exercisable for five years from the date of issuance. The Company accounts for these warrants as a liability instrument measured at estimated fair value. The initial fair value of the warrants was determined using a calibration model that involved using the Black-Scholes Pricing Model ("Black-Scholes"), which requires inputs such as the risk-free interest rate, expected share price volatility, underlying price per share of the Company's common stock and remaining term of the warrants. The warrants are subject to remeasurement at each balance sheet date, using Black-Scholes, with any changes in the fair value of the outstanding warrants recognized in the condensed consolidated statements of operations. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker in making decisions regarding resource allocation and assessing performance. The Company has one operating segment. Customer Concentration For the three-month and nine-month periods ended September 30, 2016 and 2015, the Company’s revenue had been generated solely from funding pursuant to U.S. government contracts, and accordingly all contracts receivable relate to funding from U.S. government contracts. Concentration of Credit Risk Financial instruments that potentially subject the Company to a significant concentration of credit risk consist of cash, cash equivalents and short-term investments. Cash and cash equivalents are deposited in checking and money market accounts at one financial institution with balances that generally exceed federally insured limits. Management believes that the financial institution is financially sound, and, accordingly, minimal credit risk exists with respect to this financial institution. Our investment policy limits investments to certain types of debt securities issued by the U.S. government, its agencies and institutions with investment-grade credit ratings and places restrictions on maturities and concentration by type and issuer. The Company is exposed to credit risk in the event of default by the institutions holding its cash and cash equivalents or issuing the debt securities. As of September 30, 2016 and December 31, 2015, the Company had not experienced any credit losses in such accounts or investments. Revenue Recognition The Company recognizes revenue when: (i) evidence of an arrangement exists, (ii) fees are fixed or determinable, (iii) services have been delivered, and (iv) collectability is reasonably assured. The Company currently generates revenue entirely from government contracts. Government contracts are agreements that provide the Company with payments for certain types of expenditures in return for research and development activities over a contractually-defined period. Revenue from government contracts is recognized in the period during which the related costs are incurred and the related services are rendered, provided that the applicable conditions under the government contracts have been met. Costs of contract revenue are recorded as a component of operating expenses in the Company's consolidated statement of operations. Funds received from third parties under contract arrangements are recorded as revenue if the Company is deemed to be the principal participant in the contract arrangements because the activities under the contracts are part of the Company’s development programs. If the Company is not the principal participant, the funds from contracts are recorded as a reduction to research and development expense. Contract funds received are not refundable and are recognized when the related qualified research and development costs are incurred and when there is reasonable assurance that the funds will be received. Funds billed and received in advance are recorded as deferred revenue. Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses include certain payroll and personnel expenses; laboratory supplies; consulting costs; external contract research and development expenses; and allocated overhead, including rent, equipment depreciation and utilities, and relate to both Company-sponsored programs as well as costs incurred pursuant to collaboration agreements and government contracts. The Company estimates preclinical study and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered. Advance payments for goods or services that will be used or rendered for future research and development activities are capitalized as prepaid expenses and other current assets and recognized as an expense as the goods are delivered or the related services are performed. Recent Accounting Pronouncements In August 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern (Topic 205-40), Going Concern . This ASU introduces an explicit requirement for management to assess if there is substantial doubt about an entity's ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. In connection with each annual and interim period, management must assess if there is substantial doubt about an entity's ability to continue as a going concern within one year after the issuance date. Disclosures are required if conditions give rise to substantial doubt. ASU 2014-15 is effective for all entities in the first annual period ending after December 15, 2016. The Company is currently assessing the potential effects of this ASU on its consolidated financial statements. In November 2015, the FASB issued ASU No. 2015-17, Income Taxes (Topic 740) - Balance Sheet Classification of Deferred Taxes . This guidance simplifies the presentation of deferred income taxes in a classified balance sheet to require that deferred tax liabilities and assets be classified as noncurrent and is effective for annual reporting periods, including interim reporting periods, beginning after December 15, 2016, and is applicable to the Company's fiscal year beginning January 1, 2017. Early adoption is permitted. The Company does not anticipate it will have a material impact to its consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases, which, for operating leases, requires a lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments, in its balance sheet. The standard also requires a lessee to recognize a single lease cost, calculated so that the cost of the lease is allocated over the lease term, on a generally straight-line basis. This ASU will be effective for the Company in fiscal year 2019. Early adoption is permitted. The Company is currently assessing the potential effects of this ASU on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments. This ASU clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. An entity performing the assessment under the amendments in this Update is required to assess the embedded call (put) options solely in accordance with the four-step decision sequence. This guidance should be applied on a modified retrospective basis to existing debt instruments as of the beginning of the fiscal year in which the amendments are effective, and is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company is currently assessing the potential effects of this ASU on its consolidated financial statements. In March 2016, the FASB issued ASU No 2016-09, Compensation - Stock Compensation (Topic 718) - Improvements to Employee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. In addition, the guidance allows for a policy election to account for forfeitures as they occur rather than on an estimated basis. This ASU will be effective for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. Early adoption is permitted. The Company does not anticipate that the adoption of this ASU will have a significant impact on its financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which provides a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most current revenue recognition guidance. This ASU is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606) , Deferral of the Effective Date , which defers by one year the effective date of ASU No. 2014-09 to annual reporting periods beginning after December 15, 2017 (including interim periods within those periods). Early adoption is permitted to the original effective date of December 15, 2016 (including interim periods within those periods). In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606), Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which clarifies how to identify the unit of accounting for the principal versus agent evaluation and how to apply the control principle to certain types of arrangements. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606), Identifying Performance Obligations and Licensing, which clarifies the implementation guidance on identifying performance obligations and licensing. In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606) , Narrow-Scope Improvements and Practical Expedients, which addresses certain issues on assessing collectability, presentation of sales taxes, noncash consideration, and completed contracts and contract modifications at transition. These ASUs will be effective for the Company in the first quarter of fiscal year 2018, using one of two retrospective application methods. The Company has not selected a transition method and is currently assessing the potential effects of this ASU on the Company’s condensed consolidated financial statements. Net Loss Per Share Basic net loss per common share is computed by dividing the net loss by the weighted-average number of common shares outstanding during the period. Diluted net loss per common share is computed by dividing the net loss by the weighted-average number of common shares and dilutive common share equivalents outstanding during the period. For purposes of this calculation, preferred stock, stock options, restricted stock units and warrants are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. For the three-month and nine-month periods ended September 30, 2016 and 2015, all potentially dilutive securities outstanding have been excluded from the computations of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported. Below are listed the potentially dilutive securities outstanding as of September 30, 2016 and 2015: September 30, 2016 2015 Options to purchase common stock 3,416,136 2,210,869 Restricted stock units 561,428 318,899 Warrants to purchase common stock 2,030,023 30,024 Warrants outstanding as of September 30, 2016 have a weighted-average exercise price of $3.78 .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Financial assets and liabilities are recorded at fair value. The carrying amount of certain financial instruments, including cash and cash equivalents, contracts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. Assets and liabilities recorded at fair value on a recurring basis in the consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1 : Quoted prices in active markets for identical assets or liabilities. Level 2 : Observable inputs other than Level 1 prices, 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. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. Where quoted prices are available in an active market, securities are classified as Level 1 of the valuation hierarchy. The Company’s Level 2 valuations of marketable securities are generally derived from independent pricing services based upon quoted prices in active markets for similar securities, with prices adjusted for yield and number of days to maturity, or based on industry models using data inputs, such as interest rates and prices that can be directly observed or corroborated in active markets. In certain cases, where there is limited activity or less transparency around inputs to valuation, securities are classified as Level 3 within the valuation hierarchy. Level 3 liabilities that are measured at estimated fair value on a recurring basis consist of a derivative liability in connection with loan payable and a warrant liability in connection with the Private Placement. As of September 30, 2016 and December 31 2015, financial assets and liabilities measured and recognized at fair value on a recurring basis and classified under the appropriate level of the fair value hierarchy as described above were as follows (in thousands): September 30, 2016 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Assets Cash $ 1,952 $ — $ — $ 1,952 Level 1: Restricted cash 377 — — 377 Money market funds 29,855 — — 29,855 Subtotal 30,232 — — 30,232 Level 2: Corporate debt securities 13,305 — (8 ) 13,297 Commercial paper 15,985 — — 15,985 Subtotal 29,290 — (8 ) 29,282 Total $ 61,474 $ — $ (8 ) $ 61,466 Reported as: Cash and cash equivalents $ 41,802 Short-term investments $ 19,287 Restricted cash $ 377 Liabilities, Level 3: Warrant liability in connection with Private Placement $ 5,422 Derivative liability in connection with loan payable $ 413 Total $ 5,835 December 31, 2015 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Assets Cash $ 1,013 $ — $ — $ 1,013 Level 1: Restricted cash 127 — — 127 Money market funds 19,274 — — 19,274 Subtotal 19,401 — — 19,401 Level 2: Corporate debt securities 34,490 — (47 ) 34,443 Commercial paper 1,997 — — 1,997 U.S. Treasury bills 2,005 — (1 ) 2,004 Subtotal 38,492 — (48 ) 38,444 Total $ 58,906 $ — $ (48 ) $ 58,858 Reported as: Cash and cash equivalents $ 20,287 Short-term investments $ 38,444 Restricted cash $ 127 Liabilities, Level 3: Derivative liability in connection with loan payable $ 375 All available-for-sale securities held as of September 30, 2016 had maturities less than one year from the date of acquisition. There were no sales of available-for-sale securities in any of the periods presented. The carrying value of corporate debt obligations that were in unrealized loss positions totaled $13.3 million as of September 30, 2016. The Company has determined that (i) it does not have the intent to sell any of these investments, and (ii) it is not more likely than not that it will be required to sell any of these investments before recovery of the entire amortized cost basis. The Company anticipates that it will recover the entire amortized cost basis of such corporate debt obligations and has determined that no other-than-temporary impairments associated with credit losses were required to be recognized during the three-month and nine-month periods ended September 30, 2016. Pursuant to the loan and security agreement with Solar Capital Ltd. (see Note 7), the Company entered into a Success Fee Agreement under which the Company agreed to pay $1.0 million in cash (the "Success Fee") if the Company obtains approval to market plazomicin from the Food and Drug Administration (the "FDA"). If such approval is obtained, the Success Fee shall be due the later of (i) August 5, 2019 or (ii) the date such FDA approval is obtained. The fair value of the Success Fee, approximately $375,000 at December 31, 2015, is recorded as a derivative liability and included in other long-term liabilities on the accompanying condensed consolidated balance sheet. The estimated fair value of the derivative liability as of September 30, 2016 increased by $38,000 to $413,000 from December 31, 2015, as a result of the time value of money, which is presented as change in warrant and derivative liabilities in the Company's condensed consolidated statements of operations for the nine-months ended September 30, 2016. The fair value of the derivative liability was determined using a discounted cash flow analysis, and is classified as a Level 3 measurement within the fair value hierarchy since the Company’s valuation utilized significant unobservable inputs. Specifically, the key assumptions included in the calculation of the estimated fair value of the derivative instrument include: i) the Company’s estimates of both the probability and timing of a potential $1.0 million payment to Solar Capital Ltd. upon FDA approval to market plazomicin, and ii) a discount rate of 13% which was derived from the Company's estimated cost of debt. The estimated fair value of the derivative liability is most sensitive to the probability of FDA approval. Should the probability of FDA approval change by 5% , the fair value of the derivative liability as of September 30, 2016 would change by approximately $32,000 . For the three-month period ended September 30, 2016, there was no change to the key assumptions used in the calculation of the estimated fair value. Any changes in the estimated fair values are presented as changes in warrant and derivative liabilities in the Company's condensed consolidated statements of operations. Pursuant to the Private Placement (see Note 2), the Company issued warrants to purchase 1,999,999 shares of common stock at an exercise price of $3.66 . The Company classified these warrants as a liability measured at fair value using Black-Scholes. Under certain entity conditions, the holder of a warrant may require the Company to settle the warrant in cash at its estimated fair value using Black-Scholes. On the closing date of the Private Placement, June 3, 2016, the $2.6 million initial estimated fair value of the warrants was recorded as a warrant liability on the accompanying condensed consolidated balance sheet. At September 30, 2016, the estimated fair value of the warrants was approximately $5.4 million . The change in the estimated fair value is primarily due to the increase in the Company's stock price and is included in changes in warrant and derivative liabilities in the Company's condensed consolidated statements of operations. The fair value of the warrant liability is classified as a Level 3 measurement within the fair value hierarchy since the Company’s valuation utilized significant unobservable inputs, including the risk-free interest rate, expected share price volatility, underlying price per share of the Company's common stock and remaining term of the warrants. The estimated fair values of the warrants were determined using Black-Scholes with the following assumptions, during the three-month and nine-month periods ended September 30, 2016: Three months ended September 30, Nine months ended September 30, 2016 Expected volatility 60% 60% Expected term 4.7 years 4.7–5.0 years Risk-free interest rate 1.1% 1.0%–1.2% Dividend yield 0% 0% The expected volatility is based on the Company's expected volatility. The expected term is based on the remaining life of the warrants. The risk-free interest rate is obtained from the yields on actively traded U.S. Treasury securities for a period equal to the expected term of the warrants. The dividend yield is zero because the Company has never paid cash dividends and has no present intention to pay cash dividends. Should the share price change by 5% , the fair value of the warrant liability as of September 30, 2016 would change by approximately $394,000 . Changes in the fair value of recurring measurements included in Level 3 of the fair value hierarchy are presented as changes in warrant and derivative liabilities in the Company's condensed consolidated statements of operations and were as follows for the nine-months ended September 30, 2016 (in thousands): Estimated Fair Value of Warrant Liability Estimated Fair Value of Derivative Liability Balance of Level 3 Liabilities at December 31, 2015 $ — $ 375 Estimated fair value of warrants issued 2,580 — Change in estimated fair value of warrant liability 2,842 — Change in estimated fair value of derivative liability — 38 Balance of Level 3 Liabilities at September 30, 2016 $ 5,422 $ 413

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2016
Payables and Accruals [Abstract]
Balance Sheet Components	Balance Sheet Components Accrued Liabilities Accrued liabilities consisted of the following (in thousands): September 30, December 31, 2015 Accrued clinical and development expenses $ 6,760 $ 2,869 Payroll and related bonus expenses 3,721 1,615 Other 439 443 $ 10,920 $ 4,927

License and Collaboration Agree

License and Collaboration Agreements	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Collaboration Agreements	License and Collaboration Agreements Crystal Biosciences, Inc. In May 2016, the Company entered into a collaboration and license agreement with Crystal Biosciences, Inc. (“Crystal”). Pursuant to the terms of this agreement, the Company and Crystal agreed to collaborate on the discovery of monoclonal antibodies against multiple targets. Crystal agreed to conduct the initial discovery work with its antibody platform and the Company has the right to develop and commercialize the antibodies discovered through this collaboration. The Company is required to provide signing and milestone payments with respect to research, development, regulatory and commercialization milestones (if any). All such milestone payments may total, in aggregate, up to but no more than $20,550,000 . The upfront signing fee was fully recorded as research and development expense in May 2016. This collaboration and license agreement also provides that the Company shall pay royalties equal to a low single-digit percentage of annual worldwide net sales of the commercialized product. Ionis Pharmaceuticals In January 2006, the Company entered into a license agreement with Ionis Pharmaceuticals, Inc. (“Ionis”). Ionis granted the Company an exclusive, worldwide license with the right to grant and authorize sublicenses related to the research and development of aminoglycoside products. As an up-front fee, the Company issued 97,402 shares of Series A convertible preferred stock at a fair value of $15.40 per share. This license fee of $1,500,000 was recorded as research and development expense in 2006. In further consideration of this license, and in accordance with the terms of the agreement, the Company is required to make milestone payments with respect to development, regulatory and commercialization milestones, and to pay a percentage of revenue received from sublicensees (if any). All such milestone and sublicense revenue payments may total, in the aggregate, up to but no more than $19,500,000 for the first product and $9,750,000 following the second product commercialized under the agreement with Ionis. The Company is also required to pay additional milestone payments of up to $20,000,000 in the aggregate upon the first achievement of specified threshold levels of annual net sales of all aminoglycoside products in a calendar year. The license agreement also provides that the Company shall pay royalties equal to a low single-digit percentage of annual worldwide net sales of all licensed products, including plazomicin. Through September 30, 2016, the Company had compensated Ionis $7,000,000 in connection with the first three milestones under the license for the first aminoglycoside product candidate. As of September 30, 2016 and December 31, 2015, the Company had no outstanding payments due under the agreement.

Government Contracts

Government Contracts	9 Months Ended
	Sep. 30, 2016
Contractors [Abstract]
Government Contracts	Government Contracts Certain of the Company’s drug discovery and development activities are performed under contracts with U.S. government agencies. Management has determined that the Company is the principal participant in the following contract arrangements, and, accordingly, the Company records amounts earned under the arrangements as revenue. Costs incurred under revenue contracts are recorded as operating expenses in the Company's consolidated statements of operations. Biomedical Advanced Research and Development Authority In August 2010, the Company was awarded a contract with the Biomedical Advanced Research and Development Authority (“BARDA”) for the development, manufacturing, nonclinical and clinical evaluation of, and regulatory filings for, plazomicin as a countermeasure for disease caused by antibiotic-resistant pathogens and biothreats. The original contract included committed funding of $27,600,000 for the first two years of the contract and subsequent options exercisable by BARDA to provide additional funding. In September 2012, BARDA exercised an additional $15,798,000 contract option ("Option 1"), which increased the total contract committed funding to $43,398,000 through March 2014. In April 2013, the Company was awarded an additional $60,410,000 under the contract to support its Phase 3 clinical trial of plazomicin ("Option 2") to increase the total committed funding under this contract to $103,808,000 . On May 26, 2016, the Company was awarded an additional $20 million ("Option 3") under the contract to support its Phase 3 EPIC trial of plazomicin. This brings the total committed funding under the contract to $123,808,000 . The Company recorded contract revenue of $15,431,000 and $3,783,000 under this agreement during the three-month periods ended September 30, 2016 and 2015, respectively, and $29,211,000 and $13,500,000 during the nine-month periods ended September 30, 2016 and 2015, respectively. Defense Threat Reduction Agency In November 2012, the Defense Threat Reduction Agency (“DTRA”), a division of the U.S. Department of Defense, terminated for convenience a contract with the Company to develop novel antibacterials for the treatment of biodefense pathogens. In connection with the termination, the Company sought payment from DTRA for additional expenses the Company had incurred. Effective April 30, 2015, the Company reached a settlement of its claim with DTRA. The net settlement of $7,122,000 was recorded as contract revenue during the nine months ended September 30, 2015. Together with sums previously received, it constitutes complete and final settlement of the contract. National Institute of Allergy and Infectious Diseases In July 2015, the Company was awarded a contract by the National Institute of Allergy and Infectious Diseases ("NIAID") for $1.5 million committed through September 30, 2016, with total funding of up to $4.5 million available if all options are exercised under the contract. In January 2016, an additional committed funding of $0.5 million was added to the awarded funding and the total potential funding was increased to $5.0 million . In April 2016, NIAID modified the contract to exercise an option which increased the total contract committed funding to $4.4 million through February 2018, with total potential funding remaining at $5.0 million if the remaining option is exercised. In July 2014, the Company was awarded a one -year, $407,000 grant by NIAID to conduct discovery research on novel antibiotics targeting gram-negative bacteria. In July 2015, NIAID extended the grant term through July 31, 2016. The Company recorded contract revenue of $615,000 and $693,000 under these agreements during the three-month periods ended September 30, 2016 and 2015, respectively, and $1,828,000 and $775,000 the nine-month periods ended September 30, 2016 and 2015, respectively.

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Borrowings	Borrowings Solar Capital Ltd. Loan Agreement On August 5, 2015, the Company entered into a loan and security agreement (the “Loan Agreement”) with Solar Capital Ltd. (the “Lender”) pursuant to which the Lender agreed to make available to the Company term loans in an aggregate principal amount of up to $25.0 million with a maturity date of August 5, 2019. An initial $15.0 million term loan was funded at closing on August 5, 2015, and a second $10.0 million term loan was funded on June 20, 2016. Borrowings under the term loans bear interest per annum at 6.99% plus the greater of 1% or the one-month LIBOR. The Company is currently required to make interest-only payments on the term loans through August 2017, and beginning on September 1, 2017 the Company is required to make monthly payments of interest plus equal monthly payments of principal over a term of 24 months. The Loan Agreement requires collateral by a security interest in all of the Company’s assets except intellectual property (which is subject to a negative pledge) and contains customary affirmative and negative covenants, and also includes standard events of default, including payment defaults. Upon the occurrence of an event of default, a default interest rate of an additional 4% may be applied to the outstanding loan balances, and the Lender may declare all outstanding obligations immediately due and payable and take such other actions as set forth in the Loan Agreement. There were no financial covenants attached to the loan. The Loan Agreement included a closing fee of $250,000 which was paid at closing, and the Company is obligated to pay a fee equal to 8% of the term loans funded upon the earliest to occur of the maturity date, the acceleration of the term loans or the voluntary prepayment of the term loans. The cost of these fees is being amortized as interest expense over the term of the loan using the effective-interest method. The Company may voluntarily prepay all, but not less than all, of the outstanding term loans. The Loan Agreement contains customary representations, warranties and covenants. In addition, the Loan Agreement contains customary events of default that entitle the Lender to cause the Company’s indebtedness under the Loan Agreement to become immediately due and payable. On August 5, 2015, pursuant to the Loan Agreement, the Company entered into a Success Fee Agreement with the Lender under which the Company agreed to pay the Lender $1.0 million if the Company obtains FDA approval to market plazomicin. If such approval is obtained, the Success Fee shall be due the later of (i) August 5, 2019 or (ii) the date such FDA approval is obtained. The fair value of the Success Fee at the date of issuance of approximately $356,000 was recorded as a debt discount and is being amortized as interest expense over the term of the loan using the effective-interest method. Future principal debt payments on the currently outstanding term loan are payable as follows (in thousands): September 30, 2016 2016 $ — 2017 4,167 2018 12,500 2019 8,333 Total principal payments 25,000 Final fee due at maturity in 2019 2,000 Total principal and final fee payments 27,000 Unamortized discount and debt issuance costs (1,983 ) Less current portion (1,042 ) Loan payable, long-term $ 23,975 The obligation includes a final fee of $2,000,000 , representing 8% of the term loan currently funded, which accretes over the life of the loan as interest expense. The Company recorded interest expense related to the loan of $0.7 million and $0.3 million for the three-month periods ended September 30, 2016 and 2015, respectively, and $1.6 million and $0.3 million for the nine-month periods ended September 30, 2016 and 2015, respectively.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stockholders' Equity	Stockholders' Equity On April 7, 2015, the Company entered into a Sales Agreement (the “Sales Agreement”) with Cowen and Company, LLC (“Cowen”), pursuant to which the Company may issue and sell shares of its common stock having aggregate sales proceeds of up to $30.0 million from time to time through an ATM equity program under which Cowen acts as sales agent. As of September 30, 2016, the Company had sold 1,105,549 shares of common stock under the Sales Agreement, at a weighted-average price of approximately $4.82 per share for aggregate gross proceeds of $5.3 million and net proceeds of $5.1 million after deducting the sales commissions and offering expenses. As of September 30, 2016, $24.7 million of common stock remained available to be sold under the Sales Agreement, subject to certain conditions specified therein. On June 3, 2016, the Company sold 7,999,996 shares of its common stock and warrants to purchase 1,999,999 shares of its common stock pursuant to the Purchase Agreement for aggregate gross proceeds of $25.4 million in the Private Placement. The warrants have an exercise price of $3.66 and are exercisable up to five years from the date of issuance. The Company's Chief Operating Officer, a related party, participated in the Private Placement by purchasing 141,453 shares of common stock and a warrant to purchase 35,363 shares of common stock for an aggregate purchase price of $0.5 million . Issuance costs of $0.3 million were offset against equity as a reduction from gross proceeds. At the close of the Private Placement, the estimated fair values of the common stock and warrants issued were $22.9 million and $2.6 million , respectively. At September 30, 2016, using Black-Scholes, the Company estimated the fair value of the warrant liability to be $5.4 million and recorded a charge of $1.5 million and $2.8 million , for the increase in the liability, in the condensed consolidated statements of operations, for the three-month and nine-month periods ended September 30, 2016, respectively. Equity Incentive Plans 2014 Plan In February 2014, the Company’s stockholders approved the 2014 Equity Incentive Award Plan (the "2014 Plan"), which became effective as of March 11, 2014. Under the 2014 Plan, the Company may grant incentive stock options ("ISOs"), nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock units ("RSUs") and other stock-based awards for the purchase of that number of shares of common stock. Effective, January 1, 2016, the compensation committee of the board of directors approved an evergreen increase of 735,808 shares that may be granted in accordance with the terms of the 2014 Plan. As of September 30, 2016, 626,991 shares were available for future issuance under the 2014 Plan. Under the 2014 Plan, the terms of stock award agreements, including vesting requirements, are determined by the board of directors, subject to the provisions of the 2014 Plan. Options granted by the Company typically vest over a four year period and the exercise price may not be less than fair market value on the date of grant. Certain of the options are subject to acceleration of vesting in the event of certain change of control transactions. Options granted under the 2014 Plan expire no later than 10 years from the date of grant. 2014 Employment Commencement Incentive Plan In December 2014, the Company adopted a 2014 Employment Commencement Incentive Plan (the "Inducement Plan"). The Inducement Plan is designed to comply with the inducement exemption contained in Nasdaq’s Rule 5635(c)(4), which provides for the grant of non-qualified stock options, RSUs, restricted stock awards, performance awards, dividend equivalents, deferred stock awards, deferred stock units, stock payment and stock appreciation rights to a person not previously an employee or director of the Company, or following a bona fide period of non-employment, as an inducement material to the individual’s entering into employment with the Company. As of September 30, 2016, a total of 1,150,000 shares of common stock have been authorized under the Inducement Plan, including the additional 500,000 shares that became available resulting from an amendment adopted by the board of directors as of March 17, 2016. As of September 30, 2016, 197,592 shares were available for future issuance under the Inducement Plan. 2014 Employee Stock Purchase Plan In February 2014, the Company’s stockholders approved the 2014 Employee Stock Purchase Plan (the “ESPP”), which became effective as of March 11, 2014. Effective, January 1, 2016, the compensation committee of the board of directors approved an evergreen increase of 183,952 shares that may be granted in accordance with the terms of the ESPP. As of September 30, 2016, 141,527 shares of common stock have been issued to employees participating in the ESPP, and 366,950 shares are available for issuance under the ESPP. Amended and Restated 2003 Stock Plan The Company’s Amended and Restated 2003 Stock Plan (the "2003 Plan"), provided for the granting of incentive and non-statutory stock options to employees, directors and consultants at the discretion of the board of directors. The Company granted options under its 2003 Plan until January 2014 and it was terminated as to future awards in March 2014, although it continues to govern the terms of options that remain outstanding under the 2003 Plan. Options granted under the 2003 Plan expire no later than 10 years from the date of grant. Options granted under the 2003 Plan vest over periods determined by the board of directors, generally over four years . The 2003 Plan allows for early exercise of certain options prior to vesting. Upon termination of employment, the unvested shares are subject to repurchase at the original exercise price. Stock options granted or modified after March 21, 2002, that are subsequently exercised for cash prior to vesting, are not deemed to be issued until those shares vest. As of September 30, 2016 and December 31, 2015 there were no shares subject to repurchase relating to the early exercise of options. In connection with the board of directors and stockholders approval of the 2014 Plan, all remaining shares available for future awards under the 2003 Plan were transferred to the 2014 Plan, and the 2003 Plan was terminated as to future awards. As of September 30, 2016, a total of 889,755 shares of common stock are subject to options outstanding under the 2003 plan, which shares will become available under the 2014 Plan to the extent the options are forfeited or lapse unexercised. The following table summarizes stock option activity under the stock plans, excluding the ESPP, and related information: Shares Available for Grant Shares Subject to Options Outstanding Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (years) Balance at December 31, 2015 893,462 2,387,337 $ 7.92 7.61 Additional shares authorized 1,235,808 — Options granted (1,324,600 ) 1,324,600 $ 4.01 Options exercised — (3,263 ) $ 2.45 Options cancelled 292,538 (292,538 ) $ 8.36 RSUs granted (324,650 ) — RSUs cancelled 52,025 — Balance at September 30, 2016 824,583 3,416,136 $ 6.37 8.17 Stock-based compensation expense recognized for stock options granted to employees and non-employee directors in the Company’s condensed consolidated statements of operations was as follows (in thousands): Three-Month Periods Nine-Month Periods 2016 2015 2016 2015 Research and development $ 542 $ 340 $ 1,511 $ 1,000 General and administrative 432 412 1,215 1,286 Total $ 974 $ 752 $ 2,726 $ 2,286 As of September 30, 2016, approximately $6,979,000 of total unrecognized stock-based compensation expense related to unvested stock options is expected to be recognized over a weighted-average period of 2.87 years . The estimated grant date fair value of employee stock options with time-based vesting terms was calculated using the Black-Scholes valuation model, based on the following assumptions: Three Months Ended Nine Months Ended 2016 2015 2016 2015 Expected term (years) 6.0 years 6.0 years 5.3–6.0 years 5.4–6.0 years Expected volatility 67%–68% 67%–75% 67%–74% 65%–75% Risk-free interest rate 1.1%–1.3% 1.7%–1.9% 1.1%–1.5% 1.5%–1.9% Expected dividend yield — — — — Stock Options Granted to Non-Employees During the three-month period ended September 30, 2016, the Company granted to a non-employee an option to purchase 15,000 shares of common stock. The Company did not grant stock options to non-employees during the nine-month period ended September 30, 2015. The Company recorded non-employees stock-based compensation expense of approximately $6,000 and zero for the three-month periods ended September 30, 2016 and 2015, respectively, and $6,000 and zero for the nine-month periods ended September 30, 2016 and 2015, respectively. The Company measures the estimated fair value of the award for each period until the award is fully vested. The fair value of options granted to non-employees during the three-month and nine-month periods ended September 30, 2016 was estimated using Black-Scholes with the following assumptions: Three and Nine Months Ended September 30, 2016 Expected term (years) 1.01 years Expected volatility 63% Risk-free interest rate 0.6% Expected dividend yield 0% Restricted Stock Units Granted to Employees During the nine-month period ended September 30, 2016, the Company granted RSUs to employees to receive 324,650 shares of common stock under the Company's stock plans with a weighted-average estimated grant-date fair value of $3.86 per share. RSUs generally vest annually over a 4 -year service period and vesting is contingent on continued service. As of September 30, 2016, there were unrecognized compensation costs of $2,877,000 related to outstanding RSUs, which are expected to be recognized over a weighted-average period of 2.92 years . A summary of RSU activity is as follows: RSU Awards Outstanding Number of RSUs Weighted-Average Grant Date Fair Market Value Aggregate Intrinsic Value (in thousands) Balance, December 31, 2015 372,024 $ 8.02 $ 2,135 RSUs granted 324,650 $ 3.86 RSUs released (83,221 ) $ 8.28 RSUs cancelled (52,025 ) $ 6.92 Balance, September 30, 2016 561,428 $ 5.68 $ 2,689 Stock Options and Restricted Stock Units Granted to Employees that Contain Performance Conditions During the three-month and nine-month periods ended September 30, 2016, the Company granted options to purchase an aggregate of 129,000 and 340,250 shares of common stock and 6,750 and 56,925 RSUs that vest upon the achievement of market-based common stock price targets. The fair values of these options and RSUs were estimated at the grant date using a Monte-Carlo simulation model. The Monte-Carlo simulation model requires the use of a range of assumptions. The risk-free interest rate range was 1.37% to 1.76% , expected volatility rate was 70% and the dividend rate was 0% . The expected life assumption is not used in Monte-Carlo simulation model, but the output of the model indicated an expected time to vest of 2.5 to 6.0 years. The associated stock-based compensation expense is being recognized on a straight-line basis over the implicit service period (expected time to vest) derived from that simulation model. The Company did not issue any performance based options to purchase common stock, or RSUs during the three-month and nine-month periods ended September 30, 2015.

Commitments

Commitments	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments	Commitments Nonrefundable advance payments In July 2015, the Company entered into an agreement with its pharmaceutical contract manufacturing organization that obligates it to make a total of $1.5 million of nonrefundable advance payments for the reservation of facilities and resources, plus procurement of long-lead raw materials, to produce plazomicin for regulatory commercial validation. Such advance payments are initially capitalized as prepaid and other current assets and are being recognized as research and development expenses as goods are delivered and services are performed. The Company assesses such prepaid and other current assets for impairment if events or changes in circumstances indicate that the carrying amount may not be recoverable or may not provide future economic benefits. As of September 30, 2016, the Company had recorded $0.8 million as prepaid and other current assets related to this agreement. Through September 30, 2016, the Company has recognized $0.7 million as research and development expenses. Facilities Lease Obligation The Company leases its principal executive offices in South San Francisco under a non-cancelable lease agreement that expires on April 14, 2017. In August 2016, the Company entered into a non-cancelable agreement (the "Lease") to lease approximately 47,000 square feet of office, laboratory and research and development space for the Company's new principal executive offices. The Lease is set to commence in March 2017, after the substantial completion of certain improvements ("Tenant Improvements") required under the Lease, and set to expire in August 2027 ("Lease Term"). The Lease contains expansion options and an option to extend the Lease Term for an additional 5 years . Base rent for the first year of the Lease Term is approximately $2.7 million , with an increase in annual base rent of approximately 3.5% in each subsequent year of the Lease Term. The Lease also provides for rent abatement of approximately $1.8 million for the first year of the Lease Term. The Company is entitled to a one-time improvement allowance of $5.7 million for the Tenant Improvements (the "Allowance"). The Landlord disburses the Allowance for the Tenant Improvement on behalf of the Company. In the event that the Company withdraws from the Lease prior to the commencement of the Lease, the Company will be required to reimburse the Landlord for expenditures incurred related to the Tenant Improvements. As of September 30, 2016, the Company has recorded approximately $107,000 within construction-in-progress under property, plant and equipment, net and other current liabilities in the condensed consolidated balance sheet related to costs incurred under the Allowance. At its election, the Company is also entitled to an additional improvements allowance of $0.9 million ("Additional Allowance"). In the event the Company elects to use the Additional Allowance, the base rent will be increased as calculated in the Lease. Further, the Company had a deposit of $250,000 included in long-term restricted cash as of September 30, 2016, restricted from withdrawal and held in a money market account with one of the Company’s financial institutions in the form of collateral for a letter of credit held as security for the Lease. Future minimum lease payments under the operating leases as of September 30, 2016 are as follows (in thousands): Year Ending December 31, Amounts 2016 $ 200 2017 1,103 2018 2,500 2019 2,890 2020 2,991 Thereafter 22,815 Total minimum lease payments $ 32,500 The Company recognizes rent expense on a straight-line basis over the non-cancelable lease period. Rent expense was $145,000 and $150,000 for the three-month periods ended September 30, 2016 and 2015, respectively, and $435,000 and $381,000 for the nine-month periods ended September 30, 2016 and 2015, respectively.

Organization and Basis of Pre16

Organization and Basis of Presentation and Consolidation (Policies)	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and following the requirements of the Securities and Exchange Commission (the “SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the Company’s financial information. The results of operations for the three-month and nine-month periods ended September 30, 2016 are not necessarily indicative of the results to be expected for the full year or any other future period. The balance sheet as of December 31, 2015 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. Intercompany accounts and transactions have been eliminated upon consolidation. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2015 included in the Company’s Annual Report on Form 10-K.
Use of Estimates	Use of Estimates The accompanying financial statements have been prepared in accordance with U.S. GAAP. The preparation of financial statements in conformity with U.S. GAAP requires management to make judgments, assumptions and estimates that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures of contingent liabilities. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of liabilities, common stock and stock-based awards and income taxes. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, including cash and cash equivalents, contracts receivable, prepaid and other current assets, accounts payable, accrued liabilities, and other current liabilities approximate fair value due to their short-term maturities. Short-term investments consist of available-for-sale securities and are carried at fair value. Based upon the borrowing rates (which is a Level 2 input) currently available to the Company for loans with similar terms, the Company believes the carrying amount of the loan payable approximates its fair value. The warrant and derivative liabilities are recorded at estimated fair value with changes in estimated fair value recorded in the Company's statements of operations.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents include only securities having a maturity of three months or less at the time of purchase. As of September 30, 2016 and December 31, 2015, cash and cash equivalents consisted of bank deposits, cash, commercial paper and investments in money market funds.
Short-term Investments	Short-term Investments Short-term investments consist of debt securities with maturities greater than three months, but less than one year from the date of acquisition, and are classified as available for sale. Short-term investments are carried at fair value. Unrealized gains and losses on available-for-sale securities are excluded from earnings and reported as a component of net unrealized gain (loss) on available-for-sale securities in the Company's consolidated statements of comprehensive loss. The amortized cost of debt securities reflects amortization of purchase premiums and accretion of purchase discounts to date, which are included in interest income. The Company reviews all of its marketable securities on a regular basis to evaluate whether any security has experienced an other-than-temporary decline in fair value.
Restricted Cash	Restricted Cash At September 30, 2016 and December 31, 2015, the Company had restricted cash of $377,000 and $127,000 . The restricted cash, which consists of money market accounts with one of the Company’s financial institutions, serves as collateral for the letters of credit provided as security deposits under the Company’s facility leases. As of September 30, 2016, $127,000 of restricted cash is classified as current assets and relates to the current facility lease that expires on April 14, 2017 .
Warrant Liability	Warrant Liability On June 3, 2016, the Company issued warrants to purchase 1,999,999 shares of its common stock in connection with the Private Placement. Each warrant has an exercise price of $3.66 per share and is exercisable for five years from the date of issuance. The Company accounts for these warrants as a liability instrument measured at estimated fair value. The initial fair value of the warrants was determined using a calibration model that involved using the Black-Scholes Pricing Model ("Black-Scholes"), which requires inputs such as the risk-free interest rate, expected share price volatility, underlying price per share of the Company's common stock and remaining term of the warrants. The warrants are subject to remeasurement at each balance sheet date, using Black-Scholes, with any changes in the fair value of the outstanding warrants recognized in the condensed consolidated statements of operations
Segment Reporting	Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker in making decisions regarding resource allocation and assessing performance. The Company has one operating segment.
Customer Concentration	Customer Concentration For the three-month and nine-month periods ended September 30, 2016 and 2015, the Company’s revenue had been generated solely from funding pursuant to U.S. government contracts, and accordingly all contracts receivable relate to funding from U.S. government contracts.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to a significant concentration of credit risk consist of cash, cash equivalents and short-term investments. Cash and cash equivalents are deposited in checking and money market accounts at one financial institution with balances that generally exceed federally insured limits. Management believes that the financial institution is financially sound, and, accordingly, minimal credit risk exists with respect to this financial institution. Our investment policy limits investments to certain types of debt securities issued by the U.S. government, its agencies and institutions with investment-grade credit ratings and places restrictions on maturities and concentration by type and issuer. The Company is exposed to credit risk in the event of default by the institutions holding its cash and cash equivalents or issuing the debt securities. As of September 30, 2016 and December 31, 2015, the Company had not experienced any credit losses in such accounts or investments.
Revenue Recognition	Revenue Recognition The Company recognizes revenue when: (i) evidence of an arrangement exists, (ii) fees are fixed or determinable, (iii) services have been delivered, and (iv) collectability is reasonably assured. The Company currently generates revenue entirely from government contracts. Government contracts are agreements that provide the Company with payments for certain types of expenditures in return for research and development activities over a contractually-defined period. Revenue from government contracts is recognized in the period during which the related costs are incurred and the related services are rendered, provided that the applicable conditions under the government contracts have been met. Costs of contract revenue are recorded as a component of operating expenses in the Company's consolidated statement of operations. Funds received from third parties under contract arrangements are recorded as revenue if the Company is deemed to be the principal participant in the contract arrangements because the activities under the contracts are part of the Company’s development programs. If the Company is not the principal participant, the funds from contracts are recorded as a reduction to research and development expense. Contract funds received are not refundable and are recognized when the related qualified research and development costs are incurred and when there is reasonable assurance that the funds will be received. Funds billed and received in advance are recorded as deferred revenue.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development expenses include certain payroll and personnel expenses; laboratory supplies; consulting costs; external contract research and development expenses; and allocated overhead, including rent, equipment depreciation and utilities, and relate to both Company-sponsored programs as well as costs incurred pursuant to collaboration agreements and government contracts. The Company estimates preclinical study and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered. Advance payments for goods or services that will be used or rendered for future research and development activities are capitalized as prepaid expenses and other current assets and recognized as an expense as the goods are delivered or the related services are performed.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern (Topic 205-40), Going Concern . This ASU introduces an explicit requirement for management to assess if there is substantial doubt about an entity's ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. In connection with each annual and interim period, management must assess if there is substantial doubt about an entity's ability to continue as a going concern within one year after the issuance date. Disclosures are required if conditions give rise to substantial doubt. ASU 2014-15 is effective for all entities in the first annual period ending after December 15, 2016. The Company is currently assessing the potential effects of this ASU on its consolidated financial statements. In November 2015, the FASB issued ASU No. 2015-17, Income Taxes (Topic 740) - Balance Sheet Classification of Deferred Taxes . This guidance simplifies the presentation of deferred income taxes in a classified balance sheet to require that deferred tax liabilities and assets be classified as noncurrent and is effective for annual reporting periods, including interim reporting periods, beginning after December 15, 2016, and is applicable to the Company's fiscal year beginning January 1, 2017. Early adoption is permitted. The Company does not anticipate it will have a material impact to its consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases, which, for operating leases, requires a lessee to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments, in its balance sheet. The standard also requires a lessee to recognize a single lease cost, calculated so that the cost of the lease is allocated over the lease term, on a generally straight-line basis. This ASU will be effective for the Company in fiscal year 2019. Early adoption is permitted. The Company is currently assessing the potential effects of this ASU on its consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-06, Derivatives and Hedging (Topic 815) - Contingent Put and Call Options in Debt Instruments. This ASU clarifies the requirements for assessing whether contingent call (put) options that can accelerate the payment of principal on debt instruments are clearly and closely related to their debt hosts. An entity performing the assessment under the amendments in this Update is required to assess the embedded call (put) options solely in accordance with the four-step decision sequence. This guidance should be applied on a modified retrospective basis to existing debt instruments as of the beginning of the fiscal year in which the amendments are effective, and is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The Company is currently assessing the potential effects of this ASU on its consolidated financial statements. In March 2016, the FASB issued ASU No 2016-09, Compensation - Stock Compensation (Topic 718) - Improvements to Employee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. In addition, the guidance allows for a policy election to account for forfeitures as they occur rather than on an estimated basis. This ASU will be effective for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. Early adoption is permitted. The Company does not anticipate that the adoption of this ASU will have a significant impact on its financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which provides a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most current revenue recognition guidance. This ASU is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606) , Deferral of the Effective Date , which defers by one year the effective date of ASU No. 2014-09 to annual reporting periods beginning after December 15, 2017 (including interim periods within those periods). Early adoption is permitted to the original effective date of December 15, 2016 (including interim periods within those periods). In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606), Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which clarifies how to identify the unit of accounting for the principal versus agent evaluation and how to apply the control principle to certain types of arrangements. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606), Identifying Performance Obligations and Licensing, which clarifies the implementation guidance on identifying performance obligations and licensing. In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606) , Narrow-Scope Improvements and Practical Expedients, which addresses certain issues on assessing collectability, presentation of sales taxes, noncash consideration, and completed contracts and contract modifications at transition. These ASUs will be effective for the Company in the first quarter of fiscal year 2018, using one of two retrospective application methods. The Company has not selected a transition method and is currently assessing the potential effects of this ASU on the Company’s condensed consolidated financial statements.
Net Loss Per Share	Net Loss Per Share Basic net loss per common share is computed by dividing the net loss by the weighted-average number of common shares outstanding during the period. Diluted net loss per common share is computed by dividing the net loss by the weighted-average number of common shares and dilutive common share equivalents outstanding during the period. For purposes of this calculation, preferred stock, stock options, restricted stock units and warrants are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive. For the three-month and nine-month periods ended September 30, 2016 and 2015, all potentially dilutive securities outstanding have been excluded from the computations of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Schedule of Potentially Dilutive Securities Outstanding Excluded from the Computations of Diluted Weighted-Average Shares Outstanding	Below are listed the potentially dilutive securities outstanding as of September 30, 2016 and 2015: September 30, 2016 2015 Options to purchase common stock 3,416,136 2,210,869 Restricted stock units 561,428 318,899 Warrants to purchase common stock 2,030,023 30,024

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Measured and Recognized at Fair Value	As of September 30, 2016 and December 31 2015, financial assets and liabilities measured and recognized at fair value on a recurring basis and classified under the appropriate level of the fair value hierarchy as described above were as follows (in thousands): September 30, 2016 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Assets Cash $ 1,952 $ — $ — $ 1,952 Level 1: Restricted cash 377 — — 377 Money market funds 29,855 — — 29,855 Subtotal 30,232 — — 30,232 Level 2: Corporate debt securities 13,305 — (8 ) 13,297 Commercial paper 15,985 — — 15,985 Subtotal 29,290 — (8 ) 29,282 Total $ 61,474 $ — $ (8 ) $ 61,466 Reported as: Cash and cash equivalents $ 41,802 Short-term investments $ 19,287 Restricted cash $ 377 Liabilities, Level 3: Warrant liability in connection with Private Placement $ 5,422 Derivative liability in connection with loan payable $ 413 Total $ 5,835 December 31, 2015 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Assets Cash $ 1,013 $ — $ — $ 1,013 Level 1: Restricted cash 127 — — 127 Money market funds 19,274 — — 19,274 Subtotal 19,401 — — 19,401 Level 2: Corporate debt securities 34,490 — (47 ) 34,443 Commercial paper 1,997 — — 1,997 U.S. Treasury bills 2,005 — (1 ) 2,004 Subtotal 38,492 — (48 ) 38,444 Total $ 58,906 $ — $ (48 ) $ 58,858 Reported as: Cash and cash equivalents $ 20,287 Short-term investments $ 38,444 Restricted cash $ 127 Liabilities, Level 3: Derivative liability in connection with loan payable $ 375
Schedule of Assumptions Used	The estimated fair values of the warrants were determined using Black-Scholes with the following assumptions, during the three-month and nine-month periods ended September 30, 2016: Three months ended September 30, Nine months ended September 30, 2016 Expected volatility 60% 60% Expected term 4.7 years 4.7–5.0 years Risk-free interest rate 1.1% 1.0%–1.2% Dividend yield 0% 0%
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation	Changes in the fair value of recurring measurements included in Level 3 of the fair value hierarchy are presented as changes in warrant and derivative liabilities in the Company's condensed consolidated statements of operations and were as follows for the nine-months ended September 30, 2016 (in thousands): Estimated Fair Value of Warrant Liability Estimated Fair Value of Derivative Liability Balance of Level 3 Liabilities at December 31, 2015 $ — $ 375 Estimated fair value of warrants issued 2,580 — Change in estimated fair value of warrant liability 2,842 — Change in estimated fair value of derivative liability — 38 Balance of Level 3 Liabilities at September 30, 2016 $ 5,422 $ 413

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2016
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): September 30, December 31, 2015 Accrued clinical and development expenses $ 6,760 $ 2,869 Payroll and related bonus expenses 3,721 1,615 Other 439 443 $ 10,920 $ 4,927

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Schedule of Future Minimum Debt Obligation Payments	Future principal debt payments on the currently outstanding term loan are payable as follows (in thousands): September 30, 2016 2016 $ — 2017 4,167 2018 12,500 2019 8,333 Total principal payments 25,000 Final fee due at maturity in 2019 2,000 Total principal and final fee payments 27,000 Unamortized discount and debt issuance costs (1,983 ) Less current portion (1,042 ) Loan payable, long-term $ 23,975

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	The following table summarizes stock option activity under the stock plans, excluding the ESPP, and related information: Shares Available for Grant Shares Subject to Options Outstanding Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (years) Balance at December 31, 2015 893,462 2,387,337 $ 7.92 7.61 Additional shares authorized 1,235,808 — Options granted (1,324,600 ) 1,324,600 $ 4.01 Options exercised — (3,263 ) $ 2.45 Options cancelled 292,538 (292,538 ) $ 8.36 RSUs granted (324,650 ) — RSUs cancelled 52,025 — Balance at September 30, 2016 824,583 3,416,136 $ 6.37 8.17
Schedule of Stock-based Compensation Expense for Stock Options Granted to Employees and Non-employees	Stock-based compensation expense recognized for stock options granted to employees and non-employee directors in the Company’s condensed consolidated statements of operations was as follows (in thousands): Three-Month Periods Nine-Month Periods 2016 2015 2016 2015 Research and development $ 542 $ 340 $ 1,511 $ 1,000 General and administrative 432 412 1,215 1,286 Total $ 974 $ 752 $ 2,726 $ 2,286
Schedule of Estimated Grant Date Fair Value of Employee Stock Options Using Black-Scholes Valuation Model	The estimated grant date fair value of employee stock options with time-based vesting terms was calculated using the Black-Scholes valuation model, based on the following assumptions: Three Months Ended Nine Months Ended 2016 2015 2016 2015 Expected term (years) 6.0 years 6.0 years 5.3–6.0 years 5.4–6.0 years Expected volatility 67%–68% 67%–75% 67%–74% 65%–75% Risk-free interest rate 1.1%–1.3% 1.7%–1.9% 1.1%–1.5% 1.5%–1.9% Expected dividend yield — — — —
Schedule of Stock Options Granted to Non-Employees	The fair value of options granted to non-employees during the three-month and nine-month periods ended September 30, 2016 was estimated using Black-Scholes with the following assumptions: Three and Nine Months Ended September 30, 2016 Expected term (years) 1.01 years Expected volatility 63% Risk-free interest rate 0.6% Expected dividend yield 0%
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	A summary of RSU activity is as follows: RSU Awards Outstanding Number of RSUs Weighted-Average Grant Date Fair Market Value Aggregate Intrinsic Value (in thousands) Balance, December 31, 2015 372,024 $ 8.02 $ 2,135 RSUs granted 324,650 $ 3.86 RSUs released (83,221 ) $ 8.28 RSUs cancelled (52,025 ) $ 6.92 Balance, September 30, 2016 561,428 $ 5.68 $ 2,689

Commitments Commitments (Tables

Commitments Commitments (Tables)	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	Future minimum lease payments under the operating leases as of September 30, 2016 are as follows (in thousands): Year Ending December 31, Amounts 2016 $ 200 2017 1,103 2018 2,500 2019 2,890 2020 2,991 Thereafter 22,815 Total minimum lease payments $ 32,500

Organization and Basis of Pre23

Organization and Basis of Presentation and Consolidation - (Detail) - USD ($)	Jun. 03, 2016	Mar. 31, 2014	Sep. 30, 2016	Dec. 31, 2015	Apr. 07, 2015
Subsidiary, Sale of Stock [Line Items]
Shares issued		6,900,000
Warrants to purchase common stock, exercise price (dollars per share)			$ 3.78
Value authorized of equity instruments to be issued					$ 150,000,000
Shares issued for underwriters' granted of their over-allotment option (shares)		900,000
Net proceeds from initial public offering		$ 73,900,000
Preferred shares converted (shares)		10,386,894
Cash, cash equivalents and short-term investments			$ 61,100,000
Accumulated deficit			$ 217,496,000	$ 175,993,000
Common Stock
Subsidiary, Sale of Stock [Line Items]
Shares issued			1,105,549
Value authorized of equity instruments to be issued					$ 30,000,000
Share price (dollars per share)			$ 4.82
Proceeds from issuance of common stock, gross of issuance costs			$ 5,300,000
Proceeds from sale of stock, net of commissions and other transaction costs			$ 5,100,000
Private Placement
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance or sale of equity	$ 25,400,000
Aggregate net proceeds from issuance of common stock	$ 25,100,000
Warrants to purchase common stock, exercise price (dollars per share)	$ 3.66
Weighted average contractual term	5 years
Private Placement | Maximum
Subsidiary, Sale of Stock [Line Items]
Weighted average contractual term	5 years
Private Placement | Common Stock
Subsidiary, Sale of Stock [Line Items]
Shares issued	7,999,996
Number of shares authorized to be purchased	1,999,999

Summary of Significant Accoun24

Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Thousands	Jun. 03, 2016$ / sharesshares	Sep. 30, 2016USD ($)Segment$ / shares	Dec. 31, 2015USD ($)
Accounting Policies [Abstract]
Restricted cash | $		$ 377	$ 127
Restricted cash, current | $		$ 127	$ 0
Subsidiary, Sale of Stock [Line Items]
Warrants to purchase common stock, exercise price (dollars per share) | $ / shares		$ 3.78
Number of operating segments | Segment		1
Private Placement
Subsidiary, Sale of Stock [Line Items]
Warrants to purchase common stock, exercise price (dollars per share) | $ / shares	$ 3.66
Weighted average contractual term	5 years
Common Stock | Private Placement
Subsidiary, Sale of Stock [Line Items]
Number of shares authorized to be purchased | shares	1,999,999

Summary of Significant Accoun25

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Outstanding Excluded from the Computations of Diluted Weighted-Average Shares Outstanding (Detail) - $ / shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrants to purchase common stock, exercise price (dollars per share)	$ 3.78
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding (shares)	3,416,136	2,210,869
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding (shares)	561,428	318,899
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding (shares)	2,030,023	30,024

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Measured and Recognized at Fair Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Assets
Restricted cash	$ 377	$ 127
Reported as:
Cash and cash equivalents	41,802	20,287	$ 35,062	$ 18,881
Short-term investments	19,287	38,444
Liabilities, Level 3:
Derivative liability	5,422	0
Fair Value, Measurements, Recurring
Assets
Cash	1,952	1,013
Restricted cash	377	127
Level 2:
Unrealized Gains	0	0
Unrealized Losses	(8)	(48)
Total Amortized Cost	61,474	58,906
Total Fair Value	61,466	58,858
Reported as:
Cash and cash equivalents	41,802	20,287
Short-term investments	19,287	38,444
Fair Value, Measurements, Recurring | Level 1
Assets
Restricted cash	377	127
Level 1:
Money market funds	29,855	19,274
Subtotal	30,232	19,401
Fair Value, Measurements, Recurring | Level 2
Level 2:
Amortized Cost	29,290	38,492
Unrealized Gains	0	0
Unrealized Losses	(8)	(48)
Fair Value	29,282	38,444
Fair Value, Measurements, Recurring | Level 3
Liabilities, Level 3:
Derivative liability		375
Total	5,835
Fair Value, Measurements, Recurring | Level 3 | Warrant liability in connection with Private Placement
Liabilities, Level 3:
Derivative liability	5,422
Total	5,422	0
Fair Value, Measurements, Recurring | Level 3 | Derivative liability in connection with loan payable
Liabilities, Level 3:
Derivative liability	413
Total	413	375
Corporate debt securities | Fair Value, Measurements, Recurring | Level 2
Level 2:
Amortized Cost	13,305	34,490
Unrealized Gains	0
Unrealized Losses	(8)	(47)
Fair Value	13,297	34,443
Commercial paper | Fair Value, Measurements, Recurring | Level 2
Level 2:
Amortized Cost	15,985	1,997
Unrealized Gains	0
Unrealized Losses	0	0
Fair Value	$ 15,985	1,997
U.S. Treasury bills | Fair Value, Measurements, Recurring | Level 2
Level 2:
Amortized Cost		2,005
Unrealized Losses		(1)
Fair Value		$ 2,004

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Jun. 03, 2016	Aug. 05, 2015	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in estimated fair value				$ 2,881,000	$ 7,000
Derivative liability			$ 5,422,000	5,422,000		$ 0
Potential payment to solar capital			$ 1,000,000	$ 1,000,000
Discount rate, percent				13.00%
Dividend yield			0.00%	0.00%
Change in percent effecting fair value of derivative liability				5.00%
Effect in fair value of derivative liability due to change in percent of FDA approval probability			$ 394,000	$ 394,000
Warrants to purchase common stock, exercise price (dollars per share)			$ 3.78	$ 3.78
Private Placement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrants to purchase common stock, exercise price (dollars per share)	$ 3.66
Private Placement | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of shares authorized to be purchased	1,999,999
Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability						375,000
Fair value, derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of success fee						$ 375,000
Effect in fair value of derivative liability due to change in percent of FDA approval probability			$ 32,000	$ 32,000
Derivative liability | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in estimated fair value				38,000
Derivative liability			413,000	413,000
Estimated fair value of warrants issued				0
Warrants to purchase common stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of warrants issued	$ 2,600,000
Warrants to purchase common stock | Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in estimated fair value				2,842,000
Derivative liability			5,422,000	5,422,000
Estimated fair value of warrants issued				2,580,000
Secured Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Success fee		$ 1,000,000
Fair value of success fee		$ 356,000
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized loss position			$ 13,300,000	$ 13,300,000

Fair Value Measurements - Assum

Fair Value Measurements - Assumptions Used (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Expected volatility	60.00%	60.00%
Dividend yield	0.00%	0.00%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Expected term		5 years
Risk-free interest rate	1.10%	1.20%
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Expected term	4 years 8 months	4 years 8 months 12 days
Risk-free interest rate		1.00%

Fair Value Measurements - Chang

Fair Value Measurements - Change in Fair Value of Recurring Measurements (Details) - USD ($) $ in Thousands	Jun. 03, 2016	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Change in estimated fair value		$ 2,881	$ 7
Fair Value, Measurements, Recurring | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of Level 3 Liabilities at September 30, 2016		5,835
Warrants to purchase common stock
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Estimated fair value of warrants issued	$ 2,600
Warrants to purchase common stock | Fair Value, Measurements, Recurring | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of Level 3 Liabilities at December 31, 2015		0
Estimated fair value of warrants issued		2,580
Change in estimated fair value		2,842
Balance of Level 3 Liabilities at September 30, 2016		5,422
Derivative liability | Fair Value, Measurements, Recurring | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance of Level 3 Liabilities at December 31, 2015		375
Estimated fair value of warrants issued		0
Change in estimated fair value		38
Balance of Level 3 Liabilities at September 30, 2016		$ 413

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued clinical and development expenses	$ 6,760	$ 2,869
Payroll and related bonus expenses	3,721	1,615
Other	439	443
Accrued liabilities	$ 10,920	$ 4,927

License and Collaboration Agr31

License and Collaboration Agreements - (Detail)	1 Months Ended		3 Months Ended		9 Months Ended
	May 31, 2016USD ($)	Jan. 31, 2006USD ($)$ / sharesshares	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)milestone	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development expense			$ 20,536,000	$ 10,000,000	$ 56,137,000	$ 27,967,000
Crystal Biosciences, Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments for first commercialization product	$ 20,550,000
Ionis Pharmaceuticals License Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments for first commercialization product		$ 19,500,000
Milestone payments for second commercialization product		9,750,000
Aggregate additional milestone payments		20,000,000
Cumulative milestones compensation					$ 7,000,000
Number of milestones paid in relation to license agreement | milestone					3
Payments due			$ 0		$ 0		$ 0
Ionis Pharmaceuticals License Agreement | Up-front License Fee
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Research and development expense		$ 1,500,000
Ionis Pharmaceuticals License Agreement | Up-front License Fee | Series A Convertible Preferred Stock
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Shares issued | shares		97,402
Shares issued price per share (dollars per share) | $ / shares		$ 15.40

Government Contracts - (Detail)

Government Contracts - (Detail) - USD ($)	May 26, 2016	Apr. 30, 2016	Jan. 31, 2016	Jul. 31, 2015	Jul. 31, 2014	Apr. 30, 2013	Sep. 30, 2012	Aug. 31, 2010	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Biomedical Advanced Research and Development Authority
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development contract	$ 123,808,000					$ 103,808,000	$ 43,398,000	$ 27,600,000
Term of agreement, in years								2 years
Increase in research and development contract	$ 20,000,000					$ 60,410,000	$ 15,798,000
Contracts revenue									$ 15,431,000	$ 3,783,000	$ 29,211,000	$ 13,500,000
Defense Threat Reduction Agency
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Contracts revenue												7,122,000
National Institute of Allergy and Infectious Diseases
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development contract		$ 4,400,000		$ 1,500,000	$ 407,000
Term of agreement, in years					1 year
Increase in research and development contract			$ 500,000
Contracts revenue									$ 615,000	$ 693,000	$ 1,828,000	$ 775,000
Aggregate research and development grant and other revenues		$ 5,000,000	$ 5,000,000	$ 4,500,000

Borrowings - Solar Capital Ltd.

Borrowings - Solar Capital Ltd. Loan Agreement (Details) - USD ($)	Jun. 20, 2016	Aug. 05, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Proceeds from issuance of loan payable					$ 10,000,000	$ 14,590,000
Final fee due at maturity in 2019			$ 2,000,000		2,000,000
Interest expense			670,000	$ 264,000	1,555,000	264,000
Secured Debt
Debt Instrument [Line Items]
Face amount		$ 25,000,000
Proceeds from issuance of loan payable		$ 15,000,000
Proceeds upon sale of common stock	$ 10,000,000
Interest rate per annum (percent)		6.99%
Repayment of debt term (months)		24 months
Increase in interest rate in event of default (percent)		4.00%
Closing fee		$ 250,000
Final fee (percent)		8.00%
Success fee		$ 1,000,000
Fair value of success fee		356,000
Final fee due at maturity in 2019		$ 2,000,000
Interest expense			$ 700,000	$ 300,000	$ 1,600,000	$ 300,000
Secured Debt | One-month LIBOR
Debt Instrument [Line Items]
Variable interest rate (percent)		1.00%

Borrowings - Future Minimum Deb

Borrowings - Future Minimum Debt Obligation Payments (Details) $ in Thousands	Sep. 30, 2016USD ($)
Debt Disclosure [Abstract]
2,016	$ 0
2,017	4,167
2,018	12,500
2,019	8,333
Total principal payments	25,000
Final fee due at maturity in 2019	2,000
Total principal and final fee payments	27,000
Unamortized discount and debt issuance costs	(1,983)
Less current portion	(1,042)
Loan payable, long-term	$ 23,975

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	Jun. 03, 2016	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015	Apr. 07, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value authorized of equity instruments to be issued							$ 150,000,000
Shares issued		6,900,000
Value of common stock remaining available to be sold			$ 24,700,000	$ 24,700,000	$ 24,700,000
Warrants to purchase common stock, exercise price (dollars per share)			$ 3.78	$ 3.78	$ 3.78
Derivative liability			$ 5,422,000	$ 5,422,000	$ 5,422,000	$ 0
Level 3 | Fair Value, Measurements, Recurring
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Derivative liability						$ 375,000
Warrants to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated fair value of warrants issued	$ 2,600,000
Warrants to purchase common stock | Level 3 | Fair Value, Measurements, Recurring
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated fair value of warrants issued				2,580,000
Derivative liability			5,422,000	5,422,000	$ 5,422,000
Increase in the liability			$ 1,500,000	$ 2,800,000
Private Placement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from issuance or sale of equity	$ 25,400,000
Warrants to purchase common stock, exercise price (dollars per share)	$ 3.66
Weighted average contractual term	5 years
Payments of stock issuance costs	$ 300,000
Private Placement | Chief Operating Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued	141,453
Proceeds from issuance or sale of equity	$ 500,000
Number of shares authorized to be repurchased	35,363
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value authorized of equity instruments to be issued							$ 30,000,000
Shares issued					1,105,549
Share price (dollars per share)			$ 4.82	$ 4.82	$ 4.82
Proceeds from issuance of common stock, gross of issuance costs					$ 5,300,000
Proceeds from sale of stock, net of commissions and other transaction costs					$ 5,100,000
Common Stock | Private Placement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued	7,999,996
Number of shares authorized to be purchased	1,999,999
Estimated fair values of the common stock and warrants issued	$ 22,900,000

Stockholders' Equity - Equity I

Stockholders' Equity - Equity Incentive Plans - 2014 Plan (Details) - shares	Jan. 01, 2016	Sep. 30, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares authorized (shares)		1,235,808
Outstanding shares available for future issuance (shares)		824,583	893,462
2014 Equity Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares authorized (shares)	735,808
Outstanding shares available for future issuance (shares)		626,991
Vesting period		4 years
Option expiration period		10 years

Stockholders' Equity - Equity37

Stockholders' Equity - Equity Incentive Plans - 2014 Employment Commencement Incentive Plan (Details) - shares	Mar. 17, 2016	Sep. 30, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares authorized (shares)		1,235,808
Outstanding shares available for future issuance (shares)		824,583	893,462
2014 Employment Commencement Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (shares)		1,150,000
Additional shares authorized (shares)	500,000
Outstanding shares available for future issuance (shares)		197,592

Stockholders' Equity - Equity38

Stockholders' Equity - Equity Incentive Plans - 2014 Employee Stock Purchase Plan (Details) - shares	Jan. 01, 2016	Sep. 30, 2016	Sep. 30, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares authorized (shares)		1,235,808
Outstanding shares available for future issuance (shares)		824,583	824,583	893,462
Employee Stock Purchase Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares authorized (shares)	183,952
Common stock issued (shares)			141,527
Outstanding shares available for future issuance (shares)		366,950	366,950

Stockholders' Equity - Equity39

Stockholders' Equity - Equity Incentive Plans - Amended and Restated 2003 Stock Plan (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised (shares)	3,263
Shares subject to options outstanding (shares)	3,416,136	2,387,337
Unrecognized stock-based compensation	$ 6,979
Weighted-average period of cost expected to be recognized	2 years 10 months 12 days
Stock Incentive Plan 2003
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option expiration period	10 years
Vesting period	4 years
Options exercised (shares)	0	0
Shares subject to options outstanding (shares)	889,755

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Detail) - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Shares Available for Grant
Beginning balance (shares)	893,462
Additional shares authorized (shares)	1,235,808
Options granted (shares)	(1,324,600)
Options exercised (shares)	0
Options cancelled (shares)	292,538
Ending balance (shares)	824,583	893,462
Shares Subject to Options Outstanding
Beginning balance (shares)	2,387,337
Additional shares authorized (shares)	0
Options granted (shares)	1,324,600
Options exercised (shares)	(3,263)
Options cancelled (shares)	(292,538)
Ending balance (shares)	3,416,136	2,387,337
Weighted- Average Exercise Price
Beginning balance (shares)	$ 7.92
Options granted (shares)	4.01
Options exercised (shares)	2.45
Options cancelled (shares)	8.36
Ending balance (shares)	$ 6.37	$ 7.92
Weighted- Average Remaining Contractual Term (years)
Weighted- Average Remaining Contractual Term (years)	8 years 2 months 1 day	7 years 7 months 10 days
Restricted stock units
Shares Available for Grant
Shares granted	(324,650)
Shares cancelled	52,025
Shares Subject to Options Outstanding
Options granted (shares)	0
Options cancelled (shares)	0

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Stock-Based Compensation Expense for Stock Options Granted to Employees and Non-Employees (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 974	$ 752	$ 2,726	$ 2,286
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	542	340	1,511	1,000
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 432	$ 412	$ 1,215	$ 1,286

Stockholders' Equity - Schedu42

Stockholders' Equity - Schedule of Estimated Grant Date Fair Value of Employee Stock Options Using Black-Scholes Valuation Model (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	6 years	6 years
Expected volatility, minimum	67.00%	67.00%	67.00%	65.00%
Expected volatility, maximum	68.00%	75.00%	74.00%	75.00%
Risk-free interest rate, minimum	1.10%	1.70%	1.10%	1.50%
Risk-free interest rate maximum	1.30%	1.90%	1.50%	1.90%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)			5 years 3 months 18 days	5 years 4 months 24 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)			6 years	6 years
Non-Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	1 year 4 days
Expected volatility	63.00%
Risk-free interest rate	0.60%
Expected dividend yield	0.00%

Stockholders' Equity - Stock Op

Stockholders' Equity - Stock Options Granted to Non-Employees (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Goods and Nonemployee Services Transaction [Line Items]
Stock-based compensation expense	$ 974,000	$ 752,000	$ 2,726,000	$ 2,286,000
Non-Employees
Share-based Goods and Nonemployee Services Transaction [Line Items]
Non-employee options granted (shares)	15,000
Stock-based compensation expense	$ 6,000	$ 0	$ 6,000	$ 0
Expected term (years)			1 year 4 days
Expected volatility			63.00%
Risk-free interest rate			0.60%
Expected dividend yield			0.00%

Stockholders' Equity - Restrict

Stockholders' Equity - Restricted Stock Units Granted to Employees (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average period of cost expected to be recognized	2 years 10 months 12 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted | shares	324,650
Weighted-average grant date fair market value, shares granted (dollars per share) | $ / shares	$ 3.86
Vesting period	4 years
Unrecognized compensation costs | $	$ 2,877
Weighted-average period of cost expected to be recognized	2 years 11 months 1 day

Stockholders' Equity - Summar45

Stockholders' Equity - Summary of Restricted Stock Activity (Details) - Restricted stock units - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Number of RSUs
Beginning balance (shares)	372,024
Shares granted	324,650
Shares released	(83,221)
Shares cancelled	(52,025)
Ending balance (shares)	561,428
Weighted-Average Grant Date Fair Market Value
Beginning balance (dollars per share)	$ 8.02
Shares granted (dollars per share)	3.86
Shares released (dollars per share)	8.28
Shares canceled (dollars per share)	6.92
Ending balance (dollars per share)	$ 5.68
Aggregate Intrinsic Value (in thousands)
RSU Awards Outstanding, aggregate intrinsic value	$ 2,689	$ 2,135

Stockholders' Equity - Stock 46

Stockholders' Equity - Stock Options and Restricted Stock Units Granted to Employees that Contain Performance Conditions (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	1.10%	1.70%	1.10%	1.50%
Risk-free interest rate maximum	1.30%	1.90%	1.50%	1.90%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Expected term (years)	6 years	6 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)			5 years 3 months 18 days	5 years 4 months 24 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)			6 years	6 years
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option granted to purchase common shares (shares)	129,000		340,250
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option granted to purchase common shares (shares)	6,750		56,925
Monte Carlo Simulation
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum			1.37%
Risk-free interest rate maximum			1.76%
Expected volatility			70.00%
Monte Carlo Simulation | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)			2 years 6 months
Monte Carlo Simulation | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)			6 years

Commitments - Nonrefundable Adv

Commitments - Nonrefundable Advance Payments (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		15 Months Ended
	Jul. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016
Loss Contingencies [Line Items]
Research and development		$ 20,536	$ 10,000	$ 56,137	$ 27,967
Pharmaceutical Organization
Loss Contingencies [Line Items]
Advance payments	$ 1,500
Deferred research and development		$ 800		$ 800		$ 800
Research and development						$ 700

Commitments - Facilities Lease

Commitments - Facilities Lease Obligation (Details) ft² in Thousands, $ in Thousands	Aug. 31, 2016USD ($)ft²	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Operating Leased Assets [Line Items]
Square feet of office, laboratory and research and development space (sq feet) | ft²	47
Expansion option (in years)	5 years
First year base rent	$ 2,700
Lessor Leasing Arrangements, Operating Leases, Rental Increase, Percent	3.50%
One time, first year rent abatement	$ 1,800
One time improvement allowance	5,700
Construction-in-progress		$ 1,006		$ 1,006		$ 905
Additional allowance	$ 900
Deposit		250		250
Straight line rent expense		145	$ 150	435	$ 381
Construction-in-progress
Operating Leased Assets [Line Items]
Construction-in-progress		$ 107		$ 107

Commitments - Schedule of Futur

Commitments - Schedule of Future Minimum Lease Payments (Details) $ in Thousands	Sep. 30, 2016USD ($)
Year Ending December 31,
2,016	$ 200
2,017	1,103
2,018	2,500
2,019	2,890
2,020	2,991
Thereafter	22,815
Total minimum lease payments	$ 32,500