aTyr Pharma (ATYR) 10-K 16 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Mar. 08, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Trading Symbol	LIFE
Entity Registrant Name	aTYR PHARMA INC
Entity Central Index Key	1,339,970
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		23,748,096
Entity Public Float			$ 37,197,028

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 38,388	$ 53,025
Available-for sale investments, short-term	33,759	42,510
Prepaid expenses and other assets	2,621	2,415
Total current assets	74,768	97,950
Available-for sale investments, long-term	4,002	29,814
Property and equipment, net	1,421	1,793
Other assets	333	118
Total assets	80,524	129,675
Current liabilities:
Accounts payable	2,606	3,872
Accrued expenses	5,450	4,595
Current portion of deferred rent	130	315
Current portion of long-term debt	339	3,366
Total current liabilities	8,525	12,148
Deferred rent, net of current portion		130
Long-term debt, net of current portion and issuance costs	9,198	1,776
Other long-term liabilities		571
Commitments and contingencies (Note 5)
Stockholders’ equity:
Common stock, $0.001 par value; authorized shares – 150,000,000 and 95,500,000 at December 31, 2016 and 2015, respectively; issued and outstanding shares – 23,744,832 and 23,670,079 at December 31, 2016 and 2015, respectively	24	24
Additional paid-in capital	278,832	273,321
Accumulated other comprehensive loss	(76)	(171)
Accumulated deficit	(215,979)	(158,124)
Total stockholders’ equity	62,801	115,050
Total liabilities and stockholders’ equity	$ 80,524	$ 129,675

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	95,500,000
Common stock, shares issued	23,744,832	23,670,079
Common stock, shares outstanding	23,744,832	23,670,079

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating expenses:
Research and development	$ 42,846	$ 34,504	$ 16,777
General and administrative	15,094	13,112	6,777
Total operating expenses	57,940	47,616	23,554
Loss from operations	(57,940)	(47,616)	(23,554)
Interest income (expense), net	65	(386)	(832)
Loss on extinguishment of debt	(29)
Change in fair value of warrant liabilities		29	36
Total other income (expense)	36	(357)	(796)
Loss before income taxes	(57,904)	(47,973)	(24,350)
Income tax benefit	49
Net loss	(57,855)	(47,973)	(24,350)
Accretion to redemption value of redeemable convertible preferred stock		(15)	(416)
Net loss attributable to common stockholders	$ (57,855)	$ (47,988)	$ (24,766)
Net loss per share attributable to common stockholders, basic and diluted	$ (2.44)	$ (3.03)	$ (29.69)
Weighted average common stock shares outstanding, basic and diluted	23,681,019	15,838,353	834,221

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (57,855)	$ (47,973)	$ (24,350)
Other comprehensive gain (loss):
Change in unrealized gain (loss) on available for sale investments, net of tax	95	(171)
Comprehensive loss	$ (57,760)	$ (48,144)	$ (24,350)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Stockholder Note Receivable [Member]	Non-Controlling Interest [Member]	Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Redeemable Convertible Preferred Stock [Member]
Redeemable Convertible Preferred Stock, Beginning balance at Dec. 31, 2013								$ 93,165
Redeemable Convertible Preferred Stock, shares, Beginning balance at Dec. 31, 2013								73,487,415
Beginning balance at Dec. 31, 2013	$ (66,082)	$ 1	$ 17,373	$ (69)	$ 2,414		$ (85,801)
Beginning balance, Shares at Dec. 31, 2013		856,591
Exercise of common stock options	72		43		29
Exercise of common stock options, Shares		53,289
Changes in share repurchase liability	13		13
Stock-based compensation	1,791		1,791
Dissolution of affiliates	(2,038)		405		$ (2,443)			$ 2,038
Accretion to redemption value of redeemable convertible preferred stock	(416)		(416)					416
Net loss	(24,350)						(24,350)
Redeemable Convertible Preferred Stock, Ending balance at Dec. 31, 2014								$ 95,619
Redeemable Convertible Preferred Stock, Ending balance, shares at Dec. 31, 2014								73,487,415
Ending balance at Dec. 31, 2014	(91,010)	$ 1	19,209	(69)			(110,151)
Ending balance, Shares at Dec. 31, 2014		909,880
Issuance of Series E redeemable convertible preferred stock for cash								$ 75,650
Issuance of Series E redeemable convertible preferred stock for cash, Shares								68,166,894
Conversion of redeemable convertible preferred stock in connection with initial public offering	171,284	$ 16	171,268					$ (171,284)
Conversion of redeemable convertible preferred stock in connection with IPO, Shares		16,279,859						(141,654,309)
Issuance of common stock through initial public offering, net	75,903	$ 6	75,897
Issuance of common stock through initial public offering, net, Shares		6,164,000
Repayment of stockholder note receivable	60		(9)	$ 69
Exercise of common stock options	535	$ 1	534
Exercise of common stock options, Shares		196,500
Reclassification of preferred stock warrant liability to additional paid-in-capital	290		290
Issuance of common stock to The Scripps Research Institute	1,411		1,411
Issuance of common stock to The Scripps Research Institute, Shares		119,840
Changes in share repurchase liability	(120)		(120)
Stock-based compensation	4,856		4,856
Accretion to redemption value of redeemable convertible preferred stock	(15)		(15)					$ 15
Net unrealized gain (loss) on investments, net of tax	(171)					$ (171)
Net loss	(47,973)						(47,973)
Ending balance at Dec. 31, 2015	115,050	$ 24	273,321			(171)	(158,124)
Ending balance, Shares at Dec. 31, 2015		23,670,079
Exercise of common stock options	$ 20		20
Exercise of common stock options, Shares	15,892	17,972
Issuance of common stock pursuant to employee stock purchase plan	$ 143		143
Issuance of common stock pursuant to employee stock purchase plan, Shares		56,781
Issuance of warrants related to term loan	217		217
Changes in share repurchase liability	102		102
Stock-based compensation	5,029		5,029
Net unrealized gain (loss) on investments, net of tax	95					95
Net loss	(57,855)						(57,855)
Ending balance at Dec. 31, 2016	$ 62,801	$ 24	$ 278,832			$ (76)	$ (215,979)
Ending balance, Shares at Dec. 31, 2016		23,744,832

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (57,855)	$ (47,973)	$ (24,350)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	900	869	829
Issuance of common stock for technology		1,411
Stock-based compensation	5,029	4,856	1,791
Amortization of debt discount	173	297	426
Loss on debt extinguishment	29
Change in fair value of preferred stock warrant liability		(29)	(36)
Amortization of premium of available-for-sale investment securities	531	789	43
Deferred rent	(315)	(295)	(277)
Changes in operating assets and liabilities
Prepaid expenses and other assets	(421)	(666)	(1,043)
Accounts payable and accrued expenses	(932)	3,944	(207)
Net cash used in operating activities	(52,861)	(36,797)	(22,824)
Cash flows from investing activities:
Purchase of property and equipment	(600)	(664)	(249)
Purchases of available-for-sale investment securities	(28,089)	(109,445)	(5,397)
Maturities of available-for-sale investment securities	62,216	38,115	3,400
Net cash provided by (used in) investing activities	33,527	(71,994)	(2,246)
Cash flows from financing activities:
Issuance of preferred stock for cash, net of issuance costs		75,648
Issuance of common stock through initial public offering, net of offering costs		76,902
Costs paid in connection with initial public offering			(999)
Proceeds from issuance of common stock through option exercises	20	604	72
Proceeds from employee stock purchase plan	143
Proceeds from borrowing, net	9,736		5,000
Repayments on notes payable to bank	(5,202)	(3,237)	(1,561)
Repayment of convertible debt		(2,000)
Net cash provided by financing activities	4,697	147,917	2,512
Net change in cash and cash equivalents	(14,637)	39,126	(22,558)
Cash and cash equivalents at beginning of year	53,025	13,899	36,457
Cash and cash equivalents at the end of year	38,388	53,025	13,899
Supplemental disclosure of cash flow information:
Interest paid	225	925	415
Supplemental schedule of noncash investing and financing activities:
Issuance of warrants in connection with borrowings	217		148
Changes in share repurchase liability	$ 102	$ (120)	$ 13

Organization, Business and Basi

Organization, Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Organization, Business and Basis of Presentation	1. Organization, Business and Basis of Presentation Organization and Business We were incorporated in the state of Delaware on September 8, 2005. We are focused on the discovery and clinical development of innovative medicines for patients suffering from severe, rare diseases. Principles of Consolidation Our consolidated financial statements include our accounts, our 98% majority-owned subsidiary in Hong Kong, Pangu BioPharma Limited (Pangu BioPharma). All intercompany transactions and balances are eliminated in consolidation. Use of Estimates Our consolidated financial statements are prepared in accordance with generally accepted accounting principles (GAAP). The preparation of our consolidated financial statements requires us to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements and accompanying notes. The most significant estimates in our consolidated financial statements relate to the fair value of equity issuances and awards, and clinical trial and research and development expenses. Although these estimates are based on our knowledge of current events and actions we may undertake in the future, actual results may ultimately differ materially from these estimates and assumptions. 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. We view our operations and manage our business in one operating segment.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Cash and Cash Equivalents Cash and cash equivalents consist primarily of readily available checking, money market accounts and money market funds. We consider all highly liquid investments that mature in three months or less when purchased to be cash equivalents. Investment Securities Investment securities primarily consist of investment grade corporate debt securities, asset-backed securities, commercial paper and United States Treasury securities. We classify all investment securities as available-for-sale. Investment securities are carried at fair value, with the unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) in stockholders’ equity (deficit) until realized. Realized gains and losses from the sale of investment securities, if any, are determined on a specific identification basis. A decline in the market value of any investment security below cost that is determined to be other than temporary will result in an impairment charge to earnings and a new cost basis for the security is established. No such impairment charges were recorded for any period presented. Premiums and discounts are amortized or accreted over the life of the related security as an adjustment to yield using the straight-line method and are included in interest income. Interest income is recognized when earned. As of December 31, 2016, we held an aggregate total of $37.8 million of investment securities which consisted of corporate debt securities, asset-backed securities, commercial paper and United States Treasury securities, all of which will mature in less than one year and there was a $27,000 difference between the amortized cost and fair value of these investment securities. As of December 31, 2015, we held $72.3 million of corporate debt securities, all of which mature in less than two years, and there was $0.2 million difference between the amortized cost and fair value of these investment securities. Concentration of Credit Risk Financial instruments that potentially subject us to significant concentration of credit risk consist primarily of cash, cash equivalents and investment securities. We have established guidelines regarding diversification of investments and their maturities, which are designed to maintain principal and maximize liquidity. We maintain deposits in federally insured financial institutions in excess of federally insured limits. We have not experienced any losses in such accounts and we believe that we are not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. Property and Equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of the related assets (generally three to seven years). Leasehold improvements are stated at cost and amortized on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful life of the leasehold improvements. Repairs and maintenance costs are charged to expense as incurred . Impairment of Long-Lived Assets Long-lived assets consist primarily of property and equipment. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. While our current and historical operating losses are indicators of impairment, we believe that future cash flows to be received support the carrying value of our long-lived assets and, accordingly, have not recognized any impairment losses since inception. Accrued Expenses As part of the process of preparing our consolidated financial statements, we are required to estimate accrued expenses, including accrued research and development expenses for fees paid to investigative sites and CROs in connection with clinical trials; service providers in connection with preclinical development activities; service providers related to product manufacturing; and other professional services. The accrual process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of the actual cost. We make estimates of accrued expenses as of each balance sheet date in our consolidated financial statements based on facts and circumstances known to us at that time. Although we do not expect the estimates to be materially different from amounts actually incurred, if the estimates of the status and timing of services performed differs from the actual status and timing of services performed, we may report amounts that are too high or too low in any particular period. Deferred Rent Rent expense, including the value of tenant improvement allowances received, is recorded on a straight-line basis over the term of the lease. The difference between rent expense and amounts paid under the lease agreements is recorded as deferred rent in the accompanying consolidated balance sheets. Research and Development Costs Research and development costs are expensed as incurred. Research and development costs include: salaries and employee-related expenses, including stock-based compensation and benefits for personnel in research and product development functions; costs associated with conducting our preclinical, development and regulatory activities, including fees paid to third-party professional consultants, service providers and our scientific, therapeutic and clinical advisory boards; costs to acquire, develop and manufacture preclinical study and clinical trial materials; costs incurred under clinical trial agreements with clinical research organizations and investigative sites; costs for laboratory supplies; payments related to licensed products and technologies; allocated facilities and information technology costs; and depreciation. Patent Costs Costs related to filing and pursuing patent applications are recorded as general and administrative expense and expensed as incurred since recoverability of such expenditures is uncertain. Stock-Based Compensation Stock-based compensation expense represents the cost of the grant date fair value of employee stock option and restricted stock unit grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis and the cost of the fair value of restricted stock units recognized over the requisite period. We recognize forfeitures as they occur as a reduction of expense. For stock option grants with performance-based milestones, the expense is recorded over the service period after the achievement of the milestone is probable or the performance condition is achieved. For stock option grants with market-based conditions, the expense is recorded using the accelerated attribution method over the requisite service period for each vesting tranche. We account for stock options granted to non-employees using the fair value approach. These option grants are subject to periodic revaluation over their vesting terms. We estimate the fair value of employee and non-employee stock option grants using the Black-Scholes option pricing model. We estimate the fair value of the market-based stock option grants using a Monte Carlo simulation. The fair value of restricted stock units is determined by the closing price as of the grant date. Income Taxes We account for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income in the period that includes the enactment date. We recognize net deferred tax assets to the extent that we believe these assets are more likely than not to be realized. In making such a determination, we consider all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies and results of recent operations. If we determine that we would be able to realize the deferred tax assets in the future in excess of their net recorded amount, we would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. We record uncertain tax positions on the basis of a two-step process whereby (1) we determine whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, we recognize the largest amount of tax benefit that is more than 50% likely to be realized upon ultimate settlement with the related tax authority. We recognize interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability. In November 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2015-17, Balance Sheet Classification of Deferred Taxes We elected to early adopt this guidance prospectively beginning in the year ended December 31, 2015 and prior periods were not retrospectively adjusted. There was no material impact on the financial statements upon adoption. In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting Net Loss Per Share Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents and adjusted for the weighted average number of common shares outstanding that are subject to repurchase. We have excluded 25,984, 61,814 and 61,457 shares subject to repurchase from the weighted average number of common shares outstanding for the years ended December 31, 2016, 2015 and 2014, respectively. Diluted net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted average number of common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of redeemable convertible preferred stock, redeemable convertible preferred stock issuable upon conversion of convertible promissory note, warrants for the purchase of redeemable convertible preferred stock, warrants for common stock and options outstanding under our stock option plan. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to our net loss position. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common share equivalents): Year Ended December 31, 2016 2015 2014 Redeemable convertible preferred stock outstanding — — 9,238,868 Redeemable convertible preferred stock issuable upon conversion of convertible promissory note — — 94,455 Warrants for redeemable convertible preferred stock — — 25,970 Warrants for common stock 121,512 25,970 — Common stock options and awards 4,091,701 2,625,280 1,514,471 Employee stock purchase plan 36,836 17,363 — 4,250,049 2,668,613 10,873,764 The following table summarizes our net loss per share (in thousands, except per share data): Year Ended December 31, 2016 2015 2014 Numerator: Consolidated net loss $ (57,855 ) $ (47,973 ) $ (24,350 ) Accretion to redemption value — (15 ) (416 ) Net loss attributable to common stockholders (57,855 ) (47,988 ) (24,766 ) Denominator: Weighted average common shares outstanding 23,707,003 15,900,167 895,678 Weighted average common shares subject to repurchase (25,984 ) (61,814 ) (61,457 ) Weighted average common shares outstanding - basic and diluted 23,681,019 15,838,353 834,221 Net loss per share - basic and diluted $ (2.44 ) $ (3.03 ) $ (29.69 ) Recent Accounting Pronouncements In August 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-15, Presentation of Financial Statements — Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern In April 2015, the FASB issued ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation(Topic 718): Improvements to Employee Share-Based Payment Accounting In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments To achieve this objective, the amendments in this Update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The carrying amounts of cash equivalents, prepaid and other assets, accounts payable and accrued liabilities are considered to be representative of their respective fair values because of the short-term nature of those instruments. Based on the borrowing rates currently available to us for loans with similar terms, which is considered a Level 2 input, we believe that the fair value of our Term Loan approximates its carrying values. Investment securities are recorded at fair value. The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets. Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly. Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Financial assets measured at fair value on a recurring basis consist of investment securities. Investment securities are recorded at fair value, defined as the exit price in the principal market in which we would transact, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Level 2 securities are valued using quoted market prices for similar instruments, non-binding market prices that are corroborated by observable market data, or discounted cash flow techniques and include our investments in corporate debt securities, commercial paper, asset-backed securities and United States Treasury securities. We have no financial liabilities measured at fair value on a recurring basis. None of our non-financial assets and liabilities is recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. Assets and liabilities measured at fair value on a recurring basis are as follows (in thousands): Fair Value Measurements Using Quoted Active for Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) As of December 31, 2016: Assets: Current: Cash equivalents $ 29,251 $ 29,251 $ — $ — Available-for-sale investments, short-term: Commercial paper 7,843 — 7,843 — Corporate debt securities 20,913 — 20,913 — United States Treasury securities 5,003 5,003 — — Sub-total short-term investments 33,759 5,003 28,756 — Available-for-sale investments, long-term: Asset-backed securities 4,002 — 4,002 — Sub-total long-term investments 4,002 — 4,002 — Total assets measured at fair value $ 67,012 $ 34,254 $ 32,758 $ — As of December 31, 2015: Current: Cash equivalents $ 46,545 $ 46,545 $ — $ — Available-for-sale investments, short-term: Commercial paper 2,996 — 2,996 — Corporate debt securities 39,514 — 39,514 — Sub-total short-term investments 42,510 — 42,510 — Available-for-sale investments, long-term: Asset-backed securities 10,912 — 10,912 — Corporate debt securities 16,903 — 16,903 — United States Treasury securities 1,999 1,999 — — Sub-total long-term investments 29,814 1,999 27,815 — Total assets measured at fair value $ 118,869 $ 48,544 $ 70,325 $ — As of December 31, 2016 and 2015, available-for-sale investments are detailed as follows (in thousands): December 31, 2016 Gross Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Market Value Available-for-sale investments, short-term: Commercial paper $ 7,843 $ — $ — $ 7,843 Corporate debt securities $ 20,942 $ — $ (29 ) $ 20,913 United States Treasury securities 5,002 1 — 5,003 $ 33,787 $ 1 $ (29 ) $ 33,759 Available-for-sale investments, long-term: Asset-backed securities $ 4,001 $ 1 $ — $ 4,002 $ 4,001 $ 1 $ — $ 4,002 December 31, 2015 Gross Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Market Value Available-for-sale investments, short-term: Commercial paper $ 2,996 $ — $ — $ 2,996 Corporate debt securities 39,575 — (61 ) 39,514 $ 42,571 $ — $ (61 ) $ 42,510 Available-for-sale investments, long-term: Asset-backed securities $ 10,928 $ — $ (16 ) $ 10,912 Corporate debt securities 16,990 — (87 ) 16,903 United States Treasury securities 2,006 — (7 ) 1,999 $ 29,924 $ — $ (110 ) $ 29,814 Available-for-sale investments that are in an unrealized loss position as of December 31, 2016 are as follows (in thousands): Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 20,913 $ (29 ) As of December 31, 2016, all available-for-sale investments have contractual maturity dates less than one year. As of December 31, 2016, there are 11 available-for-sale investments in gross unrealized loss position, all of which have been in such position for less than twelve months. At each reporting date, we perform an evaluation of impairment to determine if the unrealized losses are other-than-temporary. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer, and our intent and ability to hold the investment until recovery of its amortized cost basis. We intend, and have the ability, to hold our investments in unrealized loss positions until their amortized cost basis has been recovered. Based on our evaluation, we determined that the unrealized losses were not other-than-temporary as of December 31, 2016.

Balance Sheet Details

Balance Sheet Details	12 Months Ended
	Dec. 31, 2016
Balance Sheet Details [Abstract]
Balance Sheet Details	4. Balance Sheet Details Property and equipment consist of the following (in thousands): December 31, 2016 2015 Computer and office equipment $ 401 $ 336 Scientific and laboratory equipment 3,965 3,518 Tenant improvements 1,687 1,687 6,053 5,541 Less accumulated depreciation and amortization (4,632 ) (3,748 ) $ 1,421 $ 1,793 Accrued expenses consist of the following (in thousands): December 31, 2016 2015 Accrued salaries, wages and benefits 1,977 1,710 Other accrued expenses (1) 3,473 2,885 $ 5,450 $ 4,595 (1) Other accrued expenses include expenses for clinical research organizations and contract manufacturing organizations.

Debt, Commitments and Contingen

Debt, Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Debt Instruments [Abstract]
Debt, Commitments and Contingencies	5. Debt, Commitments and Contingencies Commercial Bank Debt In each of July 2013 and June 2014, we borrowed $5.0 million under a $10.0 million loan and security agreement with SVB, which we refer to as the SVB Loan. Beginning in July 2014, we began to make payments of principal and interest which were due through the maturity date of June 1, 2017. The interest rate was a per annum fixed rate of 5.0% and 5.88% for the $5.0 million drawn in each of July 2013 and June 2014, respectively. The final payment was contractually due in June 2017 with an additional fee of $0.5 million. The SVB Loan was collateralized by all of our assets, other than our intellectual property, and contains customary affirmative and negative covenants, reporting requirements and events of default. In November 2016, pursuant to the loan and security agreement with Silicon Valley Bank (SVB) and Solar Capital Ltd. (Solar), we paid SVB the balance of $2.6 million, including interest and $0.5 million final payment, in full. Term Loan On November 18, 2016, we entered into a loan and security agreement with SVB and Solar, which we refer to as the Term Loan. SVB and Solar agreed to lend us up to $20.0 million, issuable in three separate tranches of: (i) $10.0 million which was funded on November 18, 2016; (ii) $5.0 million may be drawn down by us at any time before the earlier of June 30, 2017 or an event of default, at our discretion, subject to achievement of certain financial and clinical milestones; and (iii) $5.0 million may be drawn down by us any time after June 30, 2017 and before the earlier of December 31, 2017 or an event of default, at our discretion, subject to achievement of certain milestones specified for the second tranche and additional financial and clinical milestones. Pursuant to the Term Loan agreement, we have interest only payments through December 1, 2017 or June 1, 2018, if we draw the second tranche, followed by consecutive equal monthly payments of principal and interest in arrears through the maturity date of November 18, 2020. The Term Loan bears interest at the prime rate, as reported in The Wall Street Journal on the last date of the month preceding the month in which interest will accrue, plus 4.10%. The Term Loan also provides for a final interest payment equal to 8.75% of the funded amount, which is due when the Term Loan becomes due or upon the prepayment of the Term Loan. We have the option to prepay the outstanding balance of the loan in full, subject to a prepayment fee ranging from 1.0% to 3.0% depending upon when the prepayment occurs, including any non-usage fees. The loan agreement provides for a 2.0% non-usage fee for any unfunded amount in the event we do not draw the second tranche and third tranche, payable no later than the expiration date for the second tranche or third tranche, as applicable, or the date of cancellation of the loan due to prepayment or an event of default. We received cash proceeds of $7.3 million, net of a $2.6 million repayment of the principal, accrued interest and the $0.5 million final payment of the SVB Loan. We did not pay any termination or other fees in connection with the repayment of amounts due under the SVB Loan. In connection with the Term Loan, the debt issuance costs have been recorded as a debt discount of Term Loan in our balance sheet, which are being accreted to interest expense over the life of the Term Loan using an effective interest rate of 12.28%. The final maturity payment is being accrued over the life of the Term Loan through interest expense. Future principal payments for the Term Loan, including the final payment, are as follows (in thousands): December 31, 2016 2017 $ 249 2018 3,100 2019 3,348 2020 4,178 $ 10,875 Facility Lease In December 2011, we entered into a noncancelable operating lease that included certain tenant improvement allowances and is subject to base lease payments, which escalate over the term of the lease, additional charges for common area maintenance and other costs. The lease expires in May 2017 and we have an option to extend the lease for a period of five years. In January 2017, we extended the lease for two years to May 2019. Rent expense for the years ended December 31, 2016, 2015 and 2014 was $0.5 million, $0.4 million and $0.2 million, respectively. In conjunction with the initial lease, we borrowed $2.0 million under a subordinated unsecured convertible promissory note issued to the venture arm of our landlord. The convertible promissory note carried an annual interest rate of 8.0%. In May 2015, the $2.0 million outstanding principal balance of the convertible promissory note and the $0.5 million accrued interest on the convertible promissory note was repaid in full in connection with our IPO. In June 2016, we entered into a sublease agreement with a tenant of our landlord for additional facility space in our existing building that commenced in August 2016 and will expire in June 2017. As of December 31, 2016, future minimum payments under the non-cancelable operating lease are as follows (in thousands): Operating Lease 2017 $ 386 2018 — $ 386 Research Agreements and Funding Obligations In October 2007, we entered into a research funding and option agreement for certain technologies from The Scripps Research Institute (TSRI). Under the agreement, we provide funding to TSRI to conduct certain research activities. The agreement renews automatically for successive 12 month periods starting on May 31st of each year unless we provide 30 days’ prior written notice to terminate the agreement. TSRI has the right to terminate the agreement if we fail to make any payment under the agreement or for breach or insolvency. Under the research funding and option agreement, TSRI has granted us options to enter into license agreements to acquire rights and exclusive licenses to develop, make, have made, use, have used, import, have imported, offer to sell, sell, and have sold certain licensed products, processes and services based on certain technology arising from the sponsored research activities. Pursuant to the terms of these license agreements, TSRI is entitled to receive tiered royalties as a percentage of net sales and a percentage of nonroyalty revenue we may receive from our sublicensees or partners, with the amount owed decreasing if we enter into the applicable sublicense or partnering agreement after meeting a specified clinical milestone. In addition, we are obligated to pay TSRI up to an aggregate of $2.75 million under each license agreement upon the achievement of specific clinical and regulatory milestone events. In January 2015, we and TSRI entered into an amended and restated research funding and option agreement pursuant to which we agreed to issue 119,840 shares of our common stock to TSRI in consideration for the adjustment of sublicense payments and the assignment of certain intellectual property rights by TSRI to us. The $1.4 million fair value of the common stock issued to TSRI was recorded to research and development expense. We issued the shares of common stock to TSRI on March 31, 2015. We entered into amendments to our research funding and option agreement to provide an additional $0.9 million of funding for the year ended December 31, 2016. During the years ended December 31, 2016, 2015 and 2014, excluding the fair value of the common stock issued to TSRI described above, we recognized expense under the agreement in the amount of $1.6 million, $0.7 million and $0.6 million, respectively. A member of our board of directors is a faculty member at TSRI and such payments fund a portion of his research activities conducted at TSRI. During the years ended December 31, 2016, 2015 and 2014, we provided charitable donations to the National Foundation for Cancer Research of $0.4 million. We have requested that the donations be restricted to certain basic research in cancer biology and therapeutics, a portion of which funds research activities conducted at TSRI in the laboratory of a member of our board of directors. Manufacturing Agreements On June 16, 2015, we entered into a Master Services Agreement (the MSA) with FUJIFILM Diosynth Biotechnologies U.S.A., Inc. (Fujifilm) to complete the development of the manufacturing process and for the production of the drug substance for Resolaris, our drug in clinical development. Pursuant to the MSA, Fujifilm will provide the drug substance for Resolaris to support future clinical trials, including potential pivotal trials. Under the initial scope of work executed pursuant to the MSA, Fujifilm will conduct process optimization, scale-up and demonstration, and cGMP manufacturing of the drug substance of Resolaris, and we are required to pay Fujifilm based on development and production milestones up to the mid seven figures. In addition, we are billed for consumables on a pass-through basis and have entered into statements of work for stability studies. In the next 12 months, we are committed to pay Fujifilm approximately $0.6 million based on development and production milestones. During the year ended December 31, 2016 and 2015, expenses associated with this agreement were $8.4 million and $5.1 million, respectively. In August 2016, we entered into a Master Services Agreement with a third party contract development and manufacturing organization to complete the development of the manufacturing process and for the production of drug substance for Stalaris. We are required to pay the third party contract manufacturer a total payment in the low seven figures subject to certain rights of cancellation. In addition, we are billed for consumables on a pass-through basis. In the next 12 months, we are committed to pay the third party contract manufacturing organization approximately $2.2 million based on development and production milestones. For the year ended December 31, 2016, expenses associated with this agreement were $1.0 million.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholders' Equity	6. Stockholders’ Equity Common Stock In May 2015, in connection with our IPO, we filed an amended and restated certificate of incorporation, authorizing 150,000,000 shares of common stock and 7,285,456 shares of redeemable convertible preferred stock, and 5,000,000 shares of undesignated preferred stock. As of December 31, 2016, no preferred stock is issued and outstanding. Registration Statement on Form S-3 On June 13, 2016, we filed a Registration Statement on Form S-3 (File No. 333-211998) containing two prospectuses: (i) a base prospectus which covers the offering, issuance and sale of up to $150 million in the aggregate of an indeterminate number of shares of common stock and preferred stock, an indeterminate principal amount of debt securities and such indeterminate number of warrants and units; and (ii) a sales agreement prospectus covering the offering, issuance and sale of up to a maximum aggregate offering price of up to $20 million of our common stock that may be sold from time to time under a sales agreement with Cowen and Company, LLC (Cowen). In accordance with the terms of such sales agreement entered with Cowen, we may offer and sell shares of our common stock having an aggregate offering price of up to $35 million from time to time through Cowen. We are required to file another prospectus supplement in the event we intend to offer more than $20 million in shares of our common stock in accordance with the sales agreement. The sales agreement prospectus amount of $20 million is included in the base prospectus amount of $150 million. 2014 Stock Plan We adopted a stock option plan in 2007 (the 2007 Plan), which was subsequently amended, restated and renamed in July 2014 (the 2014 Plan) to provide for the incentive stock options, nonstatutory stock options, stock and rights to purchase restricted stock to eligible recipients. Recipients of incentive stock options are eligible to purchase shares of our common stock at an exercise price equal to no less than the estimated fair market value of such stock on the date of grant. The maximum term of options under the 2014 Plan is ten years. Options granted generally vest over four years. 2015 Stock Plan In April 2015, our board of directors adopted, and our stockholders approved, the 2014 Stock Plan (the 2015 Plan). The 2015 Plan became effective on May 6, 2015 and we ceased granting any new awards under our 2014 Plan. Awards granted under the 2014 Plan prior to our IPO that are forfeited, canceled, reacquired by us prior to vesting satisfied without the issuance of stock or otherwise terminated (other than by exercise) will be added to shares available for issuance under the 2015 Plan. A total of 1,574,566 shares of our common stock were initially reserved for issuance under the 2015 Plan. In addition, the number of shares reserved and available for issuance under the 2015 Plan will automatically increase each January 1, beginning on January 1, 2016 and thereafter until January 1, 2019, by the lesser of (i) 1,840,000 shares, (ii) 4% of the outstanding number of shares of our common stock on the immediately preceding December 31 or (iii) an amount determined by our board of directors. Pursuant to this provision, 949,793 and 946,803 additional shares were reserved for issuance under the 2015 Plan on January 1, 2017 and 2016, respectively. Shares underlying any awards under the 2015 Plan that are forfeited, canceled, reacquired by us prior to vesting, satisfied without the issuance of stock or otherwise terminated (other than by exercise) will be added to shares available for issuance under the 2015 Plan. The maximum term of options granted under 2015 Plan is ten years. For an initial grant to an employee, 25% of the options generally vest on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years. For subsequent grants to an employee, the options generally vest monthly over a four-year term. Inducement Grant In September 2016, we granted a non-qualified option to purchase 145,000 shares of our common stock at an exercise price of $3.29 per share as an inducement award in connection with the hiring of our Senior Vice President, Research. This option will vest over a period of four (4) years, with 25% vesting on the one year anniversary of the grant date and the remaining 75% vesting on a monthly basis over three years thereafter, subject to continuous employment. This option was an inducement grant issued outside of the 2015 Plan in accordance with NASDAQ Listing Rule 5635(c)(4). We intend to file a registration statement on Form S-8 to register the shares of common stock underlying this option prior to the time at which this option becomes exercisable. In addition, from time to time, we may make inducement grants of stock options to new employees. Employee Stock Purchase Plan In April 2015, our board of directors adopted, and our stockholders approved, our 2015 Employee Stock Purchase Plan (the 2015 ESPP). The 2015 ESPP became effective on May 6, 2015. A total of 227,623 shares of our common stock were initially reserved for issuance under the 2015 ESPP. In addition, the number of shares reserved and available for purchase under the 2015 ESPP will automatically increase each January 1, beginning on January 1, 2016 and thereafter until January 1, 2019, by 1% of the outstanding number of shares of our common stock on the immediately preceding December 31 or such lesser number of shares as determined by the administrator of the 2015 ESPP. Pursuant to this provision, 237,448 and 236,700 additional shares were reserved for issuance under the 2015 ESPP on January 1, 2017 and 2016, respectively. Stock-based Compensations Stock Options Stock option activity is summarized as follows: Number of Outstanding Options Weighted Average Exercise Price Weighted Remaining Contractual Term Aggregate Intrinsic Value (in 000s) Outstanding as of December 31, 2015 2,625,280 $ 8.83 Granted 2,266,419 $ 5.56 Exercised (15,892 ) $ 1.24 Canceled/forfeited/expired (860,819 ) $ 10.17 Outstanding as of December 31, 2016 4,014,988 $ 6.73 7.82 $ 519 Options vested and expected to vest as of December 31, 2016 4,014,988 $ 6.73 7.82 $ 519 Options exercisable as of December 31, 2016 1,419,562 $ 6.27 5.88 $ 519 The assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows: Years Ended December 31, 2016 2015 2014 Expected term (in years) 5.50 – 6.08 5.50 – 6.08 5.77 – 6.56 Risk-free interest rate 1.2% – 2.1% 1.5% – 1.9% 1.7% – 2.7% Expected volatility 80.7% – 84.0% 79.2% – 100.9% 111.0 % Expected dividend yield 0.0 % 0.0 % 0.0 % The assumptions used in the Black-Scholes option pricing model to determine the fair value of the ESPP offering were as follows: December 31, 2016 2015 Expected term (in years) 0.50 0.50 Risk-free interest rate 0.4% – 0.6% 0.3 % Expected volatility 75.5% – 80.8% 67.3 % Expected dividend yield 0.0 % 0.0 % Expected term . The expected term represents the period of time that options are expected to be outstanding. Because we do not have sufficient history of exercise behavior, we determine the expected life assumption using the simplified method, which is an average of the contractual term of the option and its vesting period. Risk-free interest rate. We base the risk-free interest rate assumption on the U.S. Treasury’s rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the award being valued. Expected volatility. The expected volatility assumption is based on volatilities of a peer group of similar companies whose share prices are publicly available. The peer group was developed based on companies in the biotechnology industry. Expected dividend yield. We base the expected dividend yield assumption on the fact that we have never paid cash dividends and have no present intention to pay cash dividends. Performance Options with Market Conditions In October 2015, we granted our employees and certain consultants performance options with a market condition to purchase up to an aggregate 169,402 shares of common stock at an exercise price of $10.24. Upon achievement of specified performance goals by October 2017, such performance-based options shall begin to vest over four years in equal monthly installments, otherwise the options will be subject to forfeiture. The fair value of the stock options awarded that include market-based performance conditions is estimated on the date of the grant using a Monte Carlo simulation, based on the market price of the underlying common stock, expected performance measurement period, expected peer group stock price volatility and expected risk-free interest rate. The weighted average grant date fair value was $4.23.The performance options with market conditions grants are expensed using the accelerated attribution method over the requisite service period of 4.8 years regardless of whether the market condition is achieved or earned and vest. In January 2016, we granted to our executives, employees and certain consultants performance options with a market condition to purchase up to an aggregate 396,960 shares of common stock at an exercise price of $9.13. Upon achievement of specified goals by January 4, 2018, such performance options shall begin to vest over four years in equal monthly installments, otherwise the options will be subject to forfeiture. The fair value of the performance options with a market condition is estimated on the date of the grant using a Monte Carlo simulation, based on the market price of the underlying common stock, expected performance measurement period, expected peer group stock price volatility and expected risk-free interest rate. The weighted average grant date fair value was $1.93. The performance options with market conditions grants are expensed using the accelerated attribution method over the requisite service period of 5.1 years regardless of whether the market condition is achieved or earned and vest. The assumptions used at grant date to determine the fair value of the performance options with a market condition were as follows: December 31, 2016 2015 Expected term (in years) 5.06 4.81 Risk-free interest rate 2.2 % 2.1 % Expected volatility 83.3 % 80.6 % Expected dividend yield 0.0 % 0.0 % Restricted Stock Units During the year ended December 31, 2016, we granted restricted stock units to employees. Restricted stock unit activity is summarized as follows: Number of Outstanding Restricted Stock Units Weighted Average Grant Date Fair Value Balance as of December 31, 2015 — $ — Granted 131,593 $ 4.96 Released (2,080 ) $ 5.48 Forfeited (52,800 ) $ 4.95 Balance as of December 31, 2016 76,713 $ 4.95 The allocation of stock-based compensation for all options, including performance options with market condition and restricted stock units is as follows (in thousands): Years Ended December 31, 2016 2015 2014 Research and development $ 1,876 $ 2,524 $ 527 General and administrative 3,153 2,332 1,264 $ 5,029 $ 4,856 $ 1,791 The weighted–average grant date fair value per share of stock options granted by us, excluding performance options with market conditions, during the years ended December 31, 2016, 2015 and 2014 was $3.34, $11.29 and $10.18, respectively. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2016, 2015 and 2014 was $34,000, $1.9 million and $0.4 million, respectively. As of December 31, 2016, total unrecognized share-based compensation expense related to unvested stock options and restricted stock units was approximately $9.6 million. This unrecognized cost is expected to be recognized ratably over a weighted-average period of approximately 2.9 years. During the fourth quarter of 2014, we modified certain vesting conditions of performance-based equity awards for our Chief Executive Officer which resulted in incremental share-based compensation costs of $0.7 million, of which $0.6 million was recognized as expense during the year ended December 31, 2014. In October 2015, our Compensation Committee of the Board of Directors approved an amendment to accelerate the vesting schedule of certain outstanding stock options representing 931,749 shares granted to active employees and certain consultants under the 2014 Plan to change the vesting schedule of such options from six-years to four-years retroactive to the original vesting commencement dates. We recorded $0.8 million of stock compensation expense in connection with the modification during the year ended December 31, 2015. Warrants In November 2016, in connection with the Term Loan, we issued warrants to each of SVB and Solar to purchase an aggregate of 47,771 shares of our common stock with an exercise price of $3.14 per share. The warrants are immediately exercisable and will expire on November 18, 2023, provided that such warrants have not been previously exercised or have expired in connection with certain fundamental transactions involving us. Warrants outstanding as of December 31, 2016: Number Exercise Price Expiration Outstanding Per Share Date 9,051 $ 6.63 September 2017 2,006 $ 7.48 March 2021 14,913 $ 20.12 July 2023 95,542 $ 3.14 November 2023 121,512 Common Stock Reserved for Future Issuance Common stock reserved for future issuance is as follows: As of December 31, 2016 2015 Common stock warrants 121,512 25,970 Common stock options and awards outstanding 4,091,701 2,625,280 Shares available under the 2015 Plan 510,760 903,350 Shares available under the 2015 ESPP Plan 407,542 227,623 5,131,515 3,782,223

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	7. Income Taxes Pretax earnings (loss) were generated by both domestic and foreign operations as follows (in thousands): Years Ended December 31, 2016 2015 2014 United States $ (57,096 ) $ (47,490 ) $ (34,885 ) Foreign (808 ) (483 ) 10,535 $ (57,904 ) $ (47,973 ) $ (24,350 ) A reconciliation of the expected statutory federal income tax provision to the actual income tax provision is summarized as follows (in thousands): Years Ended December 31, 2016 2015 2014 Expected income taxes benefit at federal statutory rate $ (19,687 ) $ (16,311 ) $ (8,279 ) State income taxes, net of federal benefit — — (2,023 ) Permanent items and other 675 865 368 Research credits (6,800 ) (2,674 ) (372 ) Unrecognized tax benefits 2,720 1,070 144 Foreign rate differential 141 84 (3,391 ) Change in tax rate — 3,551 — Change in valuation allowance 22,902 13,415 13,553 Income tax (benefit) expense $ (49 ) $ — $ — Deferred income taxes are provided for temporary differences in recognizing certain income and expense items for financial and tax reporting purposes. The deferred tax assets consisted primarily of the income tax benefits from net operating loss (NOL) carryforwards, research and development credits and capitalized research and development expenses, along with other accruals and reserves. Valuation allowances of $71.2 million and $48.3 million as of December 31, 2016 and 2015, respectively, have been recorded to offset deferred tax assets as realization of such assets does not meet the more-likely-than-not threshold under ASC 740, Accounting for Income Taxes Significant components of our deferred tax assets are summarized as follows (in thousands): December 31, 2016 2015 Net operating loss carryforwards $ 33,713 $ 24,869 Capitalized research and development expenses 21,624 14,181 Research credits and other state credits 9,227 3,565 Intangible assets 3,874 4,176 Reserve and accruals 2,711 1,528 Valuation allowance (71,149 ) (48,319 ) Net deferred tax assets $ — $ — As of December 31, 2016, we had approximately $87.8 million, $94.5 million, and $6.5 million of net operating loss carryforwards for federal, state, and foreign purposes, respectively, net of Section 382 limitations, available to offset future taxable income. The federal and state net operating loss carryforwards begin to expire in 2025 and 2016, respectively. California net operating loss carryforwards of $1.4 million will expire in 2017. California net operating loss carryforwards of $93.1 million will expire from 2028 through 2034. The foreign net operating losses carry over indefinitely. As of December 31, 2016, we had federal and state research and development credit carryforwards of approximately $2.8 million and $2.5 million, respectively, net of Section 382 limitations, which begin to expire in 2026 for federal purposes and carry over indefinitely for state purposes. We had $11.0 million of federal Orphan Drug Credits as of December 31, 2016, which will begin to expire in 2035. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes, We elected to early adopt this guidance prospectively beginning in the year ended December 31, 2015 and prior periods were not retrospectively adjusted. There was no material impact on the consolidated financial position or results of operations upon adoption. Utilization of the domestic NOL and research and development credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that may have occurred or that could occur in the future, as required by Section 382 and 383 of the Internal Revenue Code of 1986, as amended (the Code), as well as similar state and foreign provisions. These ownership changes may limit the amount of NOL and research and development credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an “ownership change” as defined by Section 382 of the Code results from a transaction or series of transactions over a three-year period resulting in an ownership change of more than 50 percentage points of the outstanding stock of a company by certain stockholders. Since the Company’s formation, we raised capital through the issuance of capital stock on several occasions which on its own or combined with the purchasing stockholders’ subsequent disposition of those shares, has resulted in such an ownership change, and could result in an ownership change in the future. Upon the occurrence of an ownership change under Section 382 as outlined above, utilization of the NOL and research and development credit carryforwards become subject to an annual limitation under Section 382 of the Code, which is determined by first multiplying the value of our stock at the time of the ownership change by the applicable long-term, tax-exempt rate, which could be subject to additional adjustments. Any limitation may result in expiration of a portion of the NOL or research and development credit carryforwards before utilization. We completed an analysis through September 7, 2011, and had adjusted our NOL and research and development tax credit carryforwards accordingly. Ownership changes that may have occurred subsequent to September 7, 2011, and future ownership changes, including any ownership change resulting from this offering, may further limit our ability to utilize its remaining tax attributes. We recognize a tax benefit from an uncertain tax position when it is more likely than not that the position will be sustained upon examination, including resolutions of any related appeals or litigation processes, based on the technical merits. Income tax positions must meet a more-likely-than-not recognition threshold to be recognized. Our practice is to recognize interest and penalties related to income tax matters in income tax expense. We had no accrual for interest and penalties on our balance sheet and had not recognized interest or penalties in the consolidated statements of operations for the years ended December 31, 2016, 2015 and 2014. Due to the existence of the valuation allowance, future changes in unrecognized tax benefits will not impact our effective tax rate. Uncertain tax positions are evaluated based upon the facts and circumstances that exist at each reporting period. Subsequent changes in judgment based upon new information may lead to changes in recognition, derecognition, and measurement. Adjustments may result, for example, upon resolution of an issue with the taxing authorities, or expiration of a statute of limitations barring an assessment for an issue. The activity related to our unrecognized tax benefits is summarized as follows (in thousands): December 31, 2016 2015 2014 Balance as of beginning of year $ 5,033 $ 1,106 $ 947 Increase related to prior year tax positions 1,890 2,404 — Increase related to current year tax positions 6,077 1,523 177 Other decreases — — (18 ) Balance as of end of year $ 13,000 $ 5,033 $ 1,106 We do not anticipate that the amount of unrecognized tax benefits as of December 31, 2016 will change within the next twelve months. We are subject to taxation in the United States, Hong Kong and state jurisdictions. Our tax years from inception are subject to examination by the United States, Hong Kong and California authorities due to the carry forward of unutilized NOLs and research and development credits.

Employee Benefits

Employee Benefits	12 Months Ended
	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Employee Benefits	8. Employee Benefits 401(k) Plan We maintain a defined contribution 401(k) plan available to eligible employees. Employee contributions are voluntary and are determined on an individual basis, limited to the maximum amount allowable under federal tax regulations. In April 2015, our Board of Directors approved a policy, beginning on June 1, 2015, to match employee contributions equal to 50% of the participant’s contribution of up to a maximum of 6% of the participant’s annual salary. We made discretionary contributions totaling $0.2 million and $0.1 million during the years ended December 31, 2016 and 2015, respectively.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Quarterly Financial Data (Unaudited)	9. Quarterly Financial Data (Unaudited) The following financial information reflects all normal recurring adjustments, which are, in our opinion, necessary for a fair statement of the results of the interim periods. Summarized quarterly data for 2016 and 2015 are as follows (in thousands, except per share data): For the quarters ended March 31 June 30 September 30 December 31 2016: Operating expenses $ 16,115 $ 15,433 $ 13,865 $ 12,527 Net loss (16,087 ) (15,383 ) (13,819 ) (12,566 ) Basic and diluted net loss per share $ (0.68 ) $ (0.65 ) $ (0.58 ) (0.53 ) 2015: Operating expenses $ 8,922 $ 10,898 $ 11,313 $ 16,483 Net loss (9,071 ) (11,080 ) (11,329 ) (16,493 ) Basic and diluted net loss per share $ (9.39 ) $ (0.74 ) $ (0.48 ) (0.70 ) Net loss per share is computed independently for each of the quarters presented. Therefore, the sum of the quarterly per-share calculations will not necessarily equal the annual per share calculation.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	10. Subsequent Events In January 2017, we extended our primary facility lease with our landlord through May 2019 for an additional commitment of $1.5 million.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation Our consolidated financial statements include our accounts, our 98% majority-owned subsidiary in Hong Kong, Pangu BioPharma Limited (Pangu BioPharma). All intercompany transactions and balances are eliminated in consolidation.
Use of Estimates	Use of Estimates Our consolidated financial statements are prepared in accordance with generally accepted accounting principles (GAAP). The preparation of our consolidated financial statements requires us to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements and accompanying notes. The most significant estimates in our consolidated financial statements relate to the fair value of equity issuances and awards, and clinical trial and research and development expenses. Although these estimates are based on our knowledge of current events and actions we may undertake in the future, actual results may ultimately differ materially from these estimates and assumptions.
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. We view our operations and manage our business in one operating segment.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist primarily of readily available checking, money market accounts and money market funds. We consider all highly liquid investments that mature in three months or less when purchased to be cash equivalents.
Investment Securities	Investment Securities Investment securities primarily consist of investment grade corporate debt securities, asset-backed securities, commercial paper and United States Treasury securities. We classify all investment securities as available-for-sale. Investment securities are carried at fair value, with the unrealized gains and losses, if any, reported as a component of other comprehensive income (loss) in stockholders’ equity (deficit) until realized. Realized gains and losses from the sale of investment securities, if any, are determined on a specific identification basis. A decline in the market value of any investment security below cost that is determined to be other than temporary will result in an impairment charge to earnings and a new cost basis for the security is established. No such impairment charges were recorded for any period presented. Premiums and discounts are amortized or accreted over the life of the related security as an adjustment to yield using the straight-line method and are included in interest income. Interest income is recognized when earned. As of December 31, 2016, we held an aggregate total of $37.8 million of investment securities which consisted of corporate debt securities, asset-backed securities, commercial paper and United States Treasury securities, all of which will mature in less than one year and there was a $27,000 difference between the amortized cost and fair value of these investment securities. As of December 31, 2015, we held $72.3 million of corporate debt securities, all of which mature in less than two years, and there was $0.2 million difference between the amortized cost and fair value of these investment securities.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject us to significant concentration of credit risk consist primarily of cash, cash equivalents and investment securities. We have established guidelines regarding diversification of investments and their maturities, which are designed to maintain principal and maximize liquidity. We maintain deposits in federally insured financial institutions in excess of federally insured limits. We have not experienced any losses in such accounts and we believe that we are not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.
Property and Equipment	Property and Equipment Property and equipment are stated at cost and depreciated on a straight-line basis over the estimated useful life of the related assets (generally three to seven years). Leasehold improvements are stated at cost and amortized on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful life of the leasehold improvements. Repairs and maintenance costs are charged to expense as incurred .
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets Long-lived assets consist primarily of property and equipment. An impairment loss is recorded if and when events and circumstances indicate that assets might be impaired and the undiscounted cash flows estimated to be generated by those assets are less than the carrying amount of those assets. While our current and historical operating losses are indicators of impairment, we believe that future cash flows to be received support the carrying value of our long-lived assets and, accordingly, have not recognized any impairment losses since inception.
Accrued Expenses	Accrued Expenses As part of the process of preparing our consolidated financial statements, we are required to estimate accrued expenses, including accrued research and development expenses for fees paid to investigative sites and CROs in connection with clinical trials; service providers in connection with preclinical development activities; service providers related to product manufacturing; and other professional services. The accrual process involves reviewing open contracts and purchase orders, communicating with our personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of the actual cost. We make estimates of accrued expenses as of each balance sheet date in our consolidated financial statements based on facts and circumstances known to us at that time. Although we do not expect the estimates to be materially different from amounts actually incurred, if the estimates of the status and timing of services performed differs from the actual status and timing of services performed, we may report amounts that are too high or too low in any particular period.
Deferred Rent	Deferred Rent Rent expense, including the value of tenant improvement allowances received, is recorded on a straight-line basis over the term of the lease. The difference between rent expense and amounts paid under the lease agreements is recorded as deferred rent in the accompanying consolidated balance sheets.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development costs include: salaries and employee-related expenses, including stock-based compensation and benefits for personnel in research and product development functions; costs associated with conducting our preclinical, development and regulatory activities, including fees paid to third-party professional consultants, service providers and our scientific, therapeutic and clinical advisory boards; costs to acquire, develop and manufacture preclinical study and clinical trial materials; costs incurred under clinical trial agreements with clinical research organizations and investigative sites; costs for laboratory supplies; payments related to licensed products and technologies; allocated facilities and information technology costs; and depreciation.
Patent Costs	Patent Costs Costs related to filing and pursuing patent applications are recorded as general and administrative expense and expensed as incurred since recoverability of such expenditures is uncertain.
Stock-Based Compensation	Stock-Based Compensation Stock-based compensation expense represents the cost of the grant date fair value of employee stock option and restricted stock unit grants recognized over the requisite service period of the awards (usually the vesting period) on a straight-line basis and the cost of the fair value of restricted stock units recognized over the requisite period. We recognize forfeitures as they occur as a reduction of expense. For stock option grants with performance-based milestones, the expense is recorded over the service period after the achievement of the milestone is probable or the performance condition is achieved. For stock option grants with market-based conditions, the expense is recorded using the accelerated attribution method over the requisite service period for each vesting tranche. We account for stock options granted to non-employees using the fair value approach. These option grants are subject to periodic revaluation over their vesting terms. We estimate the fair value of employee and non-employee stock option grants using the Black-Scholes option pricing model. We estimate the fair value of the market-based stock option grants using a Monte Carlo simulation. The fair value of restricted stock units is determined by the closing price as of the grant date.
Income Taxes	Income Taxes We account for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized as income in the period that includes the enactment date. We recognize net deferred tax assets to the extent that we believe these assets are more likely than not to be realized. In making such a determination, we consider all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies and results of recent operations. If we determine that we would be able to realize the deferred tax assets in the future in excess of their net recorded amount, we would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. We record uncertain tax positions on the basis of a two-step process whereby (1) we determine whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, we recognize the largest amount of tax benefit that is more than 50% likely to be realized upon ultimate settlement with the related tax authority. We recognize interest and penalties related to unrecognized tax benefits within income tax expense. Any accrued interest and penalties are included within the related tax liability. In November 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2015-17, Balance Sheet Classification of Deferred Taxes We elected to early adopt this guidance prospectively beginning in the year ended December 31, 2015 and prior periods were not retrospectively adjusted. There was no material impact on the financial statements upon adoption. In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss attributable to common stockholders by the weighted average number of common shares outstanding for the period, without consideration for common stock equivalents and adjusted for the weighted average number of common shares outstanding that are subject to repurchase. We have excluded 25,984, 61,814 and 61,457 shares subject to repurchase from the weighted average number of common shares outstanding for the years ended December 31, 2016, 2015 and 2014, respectively. Diluted net loss per share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted average number of common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of redeemable convertible preferred stock, redeemable convertible preferred stock issuable upon conversion of convertible promissory note, warrants for the purchase of redeemable convertible preferred stock, warrants for common stock and options outstanding under our stock option plan. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to our net loss position. Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common share equivalents): Year Ended December 31, 2016 2015 2014 Redeemable convertible preferred stock outstanding — — 9,238,868 Redeemable convertible preferred stock issuable upon conversion of convertible promissory note — — 94,455 Warrants for redeemable convertible preferred stock — — 25,970 Warrants for common stock 121,512 25,970 — Common stock options and awards 4,091,701 2,625,280 1,514,471 Employee stock purchase plan 36,836 17,363 — 4,250,049 2,668,613 10,873,764 The following table summarizes our net loss per share (in thousands, except per share data): Year Ended December 31, 2016 2015 2014 Numerator: Consolidated net loss $ (57,855 ) $ (47,973 ) $ (24,350 ) Accretion to redemption value — (15 ) (416 ) Net loss attributable to common stockholders (57,855 ) (47,988 ) (24,766 ) Denominator: Weighted average common shares outstanding 23,707,003 15,900,167 895,678 Weighted average common shares subject to repurchase (25,984 ) (61,814 ) (61,457 ) Weighted average common shares outstanding - basic and diluted 23,681,019 15,838,353 834,221 Net loss per share - basic and diluted $ (2.44 ) $ (3.03 ) $ (29.69 )
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-15, Presentation of Financial Statements — Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern In April 2015, the FASB issued ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation(Topic 718): Improvements to Employee Share-Based Payment Accounting In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments To achieve this objective, the amendments in this Update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230), Classification of Certain Cash Receipts and Cash Payments

Summary of Significant Accoun19

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Schedule of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share	Potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common share equivalents): Year Ended December 31, 2016 2015 2014 Redeemable convertible preferred stock outstanding — — 9,238,868 Redeemable convertible preferred stock issuable upon conversion of convertible promissory note — — 94,455 Warrants for redeemable convertible preferred stock — — 25,970 Warrants for common stock 121,512 25,970 — Common stock options and awards 4,091,701 2,625,280 1,514,471 Employee stock purchase plan 36,836 17,363 — 4,250,049 2,668,613 10,873,764
Summary of Net Loss Per Share	The following table summarizes our net loss per share (in thousands, except per share data): Year Ended December 31, 2016 2015 2014 Numerator: Consolidated net loss $ (57,855 ) $ (47,973 ) $ (24,350 ) Accretion to redemption value — (15 ) (416 ) Net loss attributable to common stockholders (57,855 ) (47,988 ) (24,766 ) Denominator: Weighted average common shares outstanding 23,707,003 15,900,167 895,678 Weighted average common shares subject to repurchase (25,984 ) (61,814 ) (61,457 ) Weighted average common shares outstanding - basic and diluted 23,681,019 15,838,353 834,221 Net loss per share - basic and diluted $ (2.44 ) $ (3.03 ) $ (29.69 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are as follows (in thousands): Fair Value Measurements Using Quoted Active for Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) As of December 31, 2016: Assets: Current: Cash equivalents $ 29,251 $ 29,251 $ — $ — Available-for-sale investments, short-term: Commercial paper 7,843 — 7,843 — Corporate debt securities 20,913 — 20,913 — United States Treasury securities 5,003 5,003 — — Sub-total short-term investments 33,759 5,003 28,756 — Available-for-sale investments, long-term: Asset-backed securities 4,002 — 4,002 — Sub-total long-term investments 4,002 — 4,002 — Total assets measured at fair value $ 67,012 $ 34,254 $ 32,758 $ — As of December 31, 2015: Current: Cash equivalents $ 46,545 $ 46,545 $ — $ — Available-for-sale investments, short-term: Commercial paper 2,996 — 2,996 — Corporate debt securities 39,514 — 39,514 — Sub-total short-term investments 42,510 — 42,510 — Available-for-sale investments, long-term: Asset-backed securities 10,912 — 10,912 — Corporate debt securities 16,903 — 16,903 — United States Treasury securities 1,999 1,999 — — Sub-total long-term investments 29,814 1,999 27,815 — Total assets measured at fair value $ 118,869 $ 48,544 $ 70,325 $ —
Schedule of Available-for-sale Investments	As of December 31, 2016 and 2015, available-for-sale investments are detailed as follows (in thousands): December 31, 2016 Gross Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Market Value Available-for-sale investments, short-term: Commercial paper $ 7,843 $ — $ — $ 7,843 Corporate debt securities $ 20,942 $ — $ (29 ) $ 20,913 United States Treasury securities 5,002 1 — 5,003 $ 33,787 $ 1 $ (29 ) $ 33,759 Available-for-sale investments, long-term: Asset-backed securities $ 4,001 $ 1 $ — $ 4,002 $ 4,001 $ 1 $ — $ 4,002 December 31, 2015 Gross Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Market Value Available-for-sale investments, short-term: Commercial paper $ 2,996 $ — $ — $ 2,996 Corporate debt securities 39,575 — (61 ) 39,514 $ 42,571 $ — $ (61 ) $ 42,510 Available-for-sale investments, long-term: Asset-backed securities $ 10,928 $ — $ (16 ) $ 10,912 Corporate debt securities 16,990 — (87 ) 16,903 United States Treasury securities 2,006 — (7 ) 1,999 $ 29,924 $ — $ (110 ) $ 29,814
Schedule of Available-for-sale Investments in Unrealized Loss Position	Available-for-sale investments that are in an unrealized loss position as of December 31, 2016 are as follows (in thousands): Estimated Fair Value Gross Unrealized Losses Corporate debt securities $ 20,913 $ (29 )

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	12 Months Ended
	Dec. 31, 2016
Balance Sheet Details [Abstract]
Summary of Property and Equipment	Property and equipment consist of the following (in thousands): December 31, 2016 2015 Computer and office equipment $ 401 $ 336 Scientific and laboratory equipment 3,965 3,518 Tenant improvements 1,687 1,687 6,053 5,541 Less accumulated depreciation and amortization (4,632 ) (3,748 ) $ 1,421 $ 1,793
Summary of Accrued Expenses	Accrued expenses consist of the following (in thousands): December 31, 2016 2015 Accrued salaries, wages and benefits 1,977 1,710 Other accrued expenses (1) 3,473 2,885 $ 5,450 $ 4,595 (1) Other accrued expenses include expenses for clinical research organizations and contract manufacturing organizations.

Debt, Commitments and Conting22

Debt, Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Instruments [Abstract]
Schedule of Future Principal Payments for Term Loan Including Final Payment	Future principal payments for the Term Loan, including the final payment, are as follows (in thousands): December 31, 2016 2017 $ 249 2018 3,100 2019 3,348 2020 4,178 $ 10,875
Schedule of Future Minimum Payments under Non-cancelable Operating Lease	As of December 31, 2016, future minimum payments under the non-cancelable operating lease are as follows (in thousands): Operating Lease 2017 $ 386 2018 — $ 386

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Summary of Stock Option Activity	Stock option activity is summarized as follows: Number of Outstanding Options Weighted Average Exercise Price Weighted Remaining Contractual Term Aggregate Intrinsic Value (in 000s) Outstanding as of December 31, 2015 2,625,280 $ 8.83 Granted 2,266,419 $ 5.56 Exercised (15,892 ) $ 1.24 Canceled/forfeited/expired (860,819 ) $ 10.17 Outstanding as of December 31, 2016 4,014,988 $ 6.73 7.82 $ 519 Options vested and expected to vest as of December 31, 2016 4,014,988 $ 6.73 7.82 $ 519 Options exercisable as of December 31, 2016 1,419,562 $ 6.27 5.88 $ 519
Summary of Assumptions Used to Determine Fair Value of Employee Stock Purchase Plan	The assumptions used in the Black-Scholes option pricing model to determine the fair value of the ESPP offering were as follows: December 31, 2016 2015 Expected term (in years) 0.50 0.50 Risk-free interest rate 0.4% – 0.6% 0.3 % Expected volatility 75.5% – 80.8% 67.3 % Expected dividend yield 0.0 % 0.0 %
Schedule of Restricted Stock Units Activity	During the year ended December 31, 2016, we granted restricted stock units to employees. Restricted stock unit activity is summarized as follows: Number of Outstanding Restricted Stock Units Weighted Average Grant Date Fair Value Balance as of December 31, 2015 — $ — Granted 131,593 $ 4.96 Released (2,080 ) $ 5.48 Forfeited (52,800 ) $ 4.95 Balance as of December 31, 2016 76,713 $ 4.95
Schedule of Allocation of Stock-Based Compensation for All Options Including Performance Options with Market Condition and Restricted Stock Units	The allocation of stock-based compensation for all options, including performance options with market condition and restricted stock units is as follows (in thousands): Years Ended December 31, 2016 2015 2014 Research and development $ 1,876 $ 2,524 $ 527 General and administrative 3,153 2,332 1,264 $ 5,029 $ 4,856 $ 1,791
Summary of Warrants Outstanding	Warrants outstanding as of December 31, 2016: Number Exercise Price Expiration Outstanding Per Share Date 9,051 $ 6.63 September 2017 2,006 $ 7.48 March 2021 14,913 $ 20.12 July 2023 95,542 $ 3.14 November 2023 121,512
Summary of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance is as follows: As of December 31, 2016 2015 Common stock warrants 121,512 25,970 Common stock options and awards outstanding 4,091,701 2,625,280 Shares available under the 2015 Plan 510,760 903,350 Shares available under the 2015 ESPP Plan 407,542 227,623 5,131,515 3,782,223
Employee Stock Option [Member]
Summary of Assumptions Used to Determine Fair Value of Employee Stock Option Grants and Performance Options with Market Condition	The assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows: Years Ended December 31, 2016 2015 2014 Expected term (in years) 5.50 – 6.08 5.50 – 6.08 5.77 – 6.56 Risk-free interest rate 1.2% – 2.1% 1.5% – 1.9% 1.7% – 2.7% Expected volatility 80.7% – 84.0% 79.2% – 100.9% 111.0 % Expected dividend yield 0.0 % 0.0 % 0.0 %
Performance Options with Market Condition [Member]
Summary of Assumptions Used to Determine Fair Value of Employee Stock Option Grants and Performance Options with Market Condition	The assumptions used at grant date to determine the fair value of the performance options with a market condition were as follows: December 31, 2016 2015 Expected term (in years) 5.06 4.81 Risk-free interest rate 2.2 % 2.1 % Expected volatility 83.3 % 80.6 % Expected dividend yield 0.0 % 0.0 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Pretax Earnings (Loss) for Domestic and Foreign Operations	Pretax earnings (loss) were generated by both domestic and foreign operations as follows (in thousands): Years Ended December 31, 2016 2015 2014 United States $ (57,096 ) $ (47,490 ) $ (34,885 ) Foreign (808 ) (483 ) 10,535 $ (57,904 ) $ (47,973 ) $ (24,350 )
Schedule of Reconciliations of the Expected Statutory Federal Income Tax	A reconciliation of the expected statutory federal income tax provision to the actual income tax provision is summarized as follows (in thousands): Years Ended December 31, 2016 2015 2014 Expected income taxes benefit at federal statutory rate $ (19,687 ) $ (16,311 ) $ (8,279 ) State income taxes, net of federal benefit — — (2,023 ) Permanent items and other 675 865 368 Research credits (6,800 ) (2,674 ) (372 ) Unrecognized tax benefits 2,720 1,070 144 Foreign rate differential 141 84 (3,391 ) Change in tax rate — 3,551 — Change in valuation allowance 22,902 13,415 13,553 Income tax (benefit) expense $ (49 ) $ — $ —
Schedule of Significant Components of Deferred Tax Assets	Significant components of our deferred tax assets are summarized as follows (in thousands): December 31, 2016 2015 Net operating loss carryforwards $ 33,713 $ 24,869 Capitalized research and development expenses 21,624 14,181 Research credits and other state credits 9,227 3,565 Intangible assets 3,874 4,176 Reserve and accruals 2,711 1,528 Valuation allowance (71,149 ) (48,319 ) Net deferred tax assets $ — $ —
Schedule of Activity Related to Unrecognized Tax Benefits	The activity related to our unrecognized tax benefits is summarized as follows (in thousands): December 31, 2016 2015 2014 Balance as of beginning of year $ 5,033 $ 1,106 $ 947 Increase related to prior year tax positions 1,890 2,404 — Increase related to current year tax positions 6,077 1,523 177 Other decreases — — (18 ) Balance as of end of year $ 13,000 $ 5,033 $ 1,106

Quarterly Financial Data (Una25

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Data [Abstract]
Summary of Quarterly Financial Data	The following financial information reflects all normal recurring adjustments, which are, in our opinion, necessary for a fair statement of the results of the interim periods. Summarized quarterly data for 2016 and 2015 are as follows (in thousands, except per share data): For the quarters ended March 31 June 30 September 30 December 31 2016: Operating expenses $ 16,115 $ 15,433 $ 13,865 $ 12,527 Net loss (16,087 ) (15,383 ) (13,819 ) (12,566 ) Basic and diluted net loss per share $ (0.68 ) $ (0.65 ) $ (0.58 ) (0.53 ) 2015: Operating expenses $ 8,922 $ 10,898 $ 11,313 $ 16,483 Net loss (9,071 ) (11,080 ) (11,329 ) (16,493 ) Basic and diluted net loss per share $ (9.39 ) $ (0.74 ) $ (0.48 ) (0.70 )

Organization, Business and Ba26

Organization, Business and Basis of Presentation - Additional Information (Detail)	Dec. 31, 2016
Pangu BioPharma [Member] | Hong Kong [Member]
Description Of Business [Line Items]
Majority-owned subsidiary percentage	98.00%

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Impairment charges on investment securities	$ 0
Aggregate value of investment securities	37,800,000
Adjustment between amortized cost and fair value of investment securities	27,000
Impairment of long lived assets	$ 0
Weighted average shares subject to repurchase	25,984	61,814	61,457
Maximum [Member]
Significant Accounting Policies [Line Items]
Maturity period of investment securities	1 year
Estimated useful life of property and equipment	7 years
Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	3 years
Percentage of tax benefit to be realized upon settlement	50.00%
Corporate Debt Securities [Member]
Significant Accounting Policies [Line Items]
Aggregate value of investment securities		$ 72,300,000
Adjustment between amortized cost and fair value of investment securities		$ 200,000
Corporate Debt Securities [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Maturity period of investment securities		2 years

Summary of Significant Accoun28

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in calculation of diluted net loss per share	4,250,049	2,668,613	10,873,764
Redeemable Convertible Preferred Stock Outstanding [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in calculation of diluted net loss per share			9,238,868
Redeemable Convertible Preferred Stock Issuable upon Conversion of Convertible Promissory Note [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in calculation of diluted net loss per share			94,455
Warrants for Redeemable Convertible Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in calculation of diluted net loss per share			25,970
Warrants for Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in calculation of diluted net loss per share	121,512	25,970
Common Stock Options and Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in calculation of diluted net loss per share	4,091,701	2,625,280	1,514,471
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in calculation of diluted net loss per share	36,836	17,363

Summary of Significant Accoun29

Summary of Significant Accounting Policies - Summary of Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Consolidated net loss	$ (12,566)	$ (13,819)	$ (15,383)	$ (16,087)	$ (16,493)	$ (11,329)	$ (11,080)	$ (9,071)	$ (57,855)	$ (47,973)	$ (24,350)
Accretion to redemption value										(15)	(416)
Net loss attributable to common stockholders									$ (57,855)	$ (47,988)	$ (24,766)
Denominator:
Weighted average common shares outstanding									23,707,003	15,900,167	895,678
Weighted average common shares subject to repurchase									(25,984)	(61,814)	(61,457)
Weighted average common shares outstanding - basic and diluted									23,681,019	15,838,353	834,221
Net loss per share - basic and diluted	$ (0.53)	$ (0.58)	$ (0.65)	$ (0.68)	$ (0.70)	$ (0.48)	$ (0.74)	$ (9.39)	$ (2.44)	$ (3.03)	$ (29.69)

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 29,251	$ 46,545
Total assets measured at fair value	67,012	118,869
Available-for-sale [Member] | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	33,759	42,510
Available-for-sale [Member] | Short-term Investments [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	7,843	2,996
Available-for-sale [Member] | Short-term Investments [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	20,913	39,514
Available-for-sale [Member] | Short-term Investments [Member] | United States Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	5,003
Available-for-sale [Member] | Long-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	4,002	29,814
Available-for-sale [Member] | Long-term Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	4,002	10,912
Available-for-sale [Member] | Long-term Investments [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value		16,903
Available-for-sale [Member] | Long-term Investments [Member] | United States Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value		1,999
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	29,251	46,545
Total assets measured at fair value	34,254	48,544
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Available-for-sale [Member] | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	5,003
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Available-for-sale [Member] | Short-term Investments [Member] | United States Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	5,003
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Available-for-sale [Member] | Long-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value		1,999
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Available-for-sale [Member] | Long-term Investments [Member] | United States Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value		1,999
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	32,758	70,325
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	28,756	42,510
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Short-term Investments [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	7,843	2,996
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Short-term Investments [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	20,913	39,514
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Long-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	4,002	27,815
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Long-term Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	$ 4,002	10,912
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Long-term Investments [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value		$ 16,903

Fair Value Measurements - Sch31

Fair Value Measurements - Schedule of Available-for-sale Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	$ 33,787	$ 42,571
Gross Unrealized Gains	1
Gross Unrealized Losses	(29)	(61)
Market Value	33,759	42,510
Short-term Investments [Member] | Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	7,843	2,996
Market Value	7,843	2,996
Short-term Investments [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	20,942	39,575
Gross Unrealized Losses	(29)	(61)
Market Value	20,913	39,514
Short-term Investments [Member] | United States Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	5,002
Gross Unrealized Gains	1
Market Value	5,003
Long-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	4,001	29,924
Gross Unrealized Gains	1
Gross Unrealized Losses		(110)
Market Value	4,002	29,814
Long-term Investments [Member] | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost		16,990
Gross Unrealized Losses		(87)
Market Value		16,903
Long-term Investments [Member] | United States Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost		2,006
Gross Unrealized Losses		(7)
Market Value		1,999
Long-term Investments [Member] | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	4,001	10,928
Gross Unrealized Gains	1
Gross Unrealized Losses		(16)
Market Value	$ 4,002	$ 10,912

Fair Value Measurements - Sch32

Fair Value Measurements - Schedule of Available-for-sale Investments in Unrealized Loss Position (Detail) - Corporate Debt Securities [Member] $ in Thousands	Dec. 31, 2016USD ($)
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 20,913
Gross Unrealized Losses	$ (29)

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016Security
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments in gross unrealized loss position	11
Available-for-sale investments in gross unrealized loss position	12 months
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments contractual maturity period	1 year

Balance Sheet Details - Summary

Balance Sheet Details - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property Plant And Equipment [Line Items]
Property and equipment, Gross	$ 6,053	$ 5,541
Less accumulated depreciation and amortization	(4,632)	(3,748)
Property and equipment, Net	1,421	1,793
Computer and Office Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, Gross	401	336
Scientific and Laboratory Equipment [Member]
Property Plant And Equipment [Line Items]
Property and equipment, Gross	3,965	3,518
Tenant Improvements [Member]
Property Plant And Equipment [Line Items]
Property and equipment, Gross	$ 1,687	$ 1,687

Balance Sheet Details - Summa35

Balance Sheet Details - Summary of Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Liabilities Current [Abstract]
Accrued salaries, wages and benefits	$ 1,977	$ 1,710
Other accrued expenses	3,473	2,885
Accrued expenses	$ 5,450	$ 4,595

Debt, Commitments and Conting36

Debt, Commitments and Contingencies - Additional Information (Detail)

Nov. 18, 2016USD ($)Tranche

Jan. 31, 2017

Nov. 30, 2016USD ($)

Jun. 30, 2016

May 31, 2015USD ($)

Jan. 31, 2015USD ($)shares

Jun. 30, 2014USD ($)

Dec. 31, 2011USD ($)

Oct. 31, 2007USD ($)

Dec. 31, 2016USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Dec. 31, 2017USD ($)

Jun. 30, 2017USD ($)

Jul. 31, 2013USD ($)

Debt Instrument [Line Items]

Repayment of debt, principal including accrued interest

$ 5,202,000

$ 3,237,000

$ 1,561,000

Loan and security agreement, payment term

(i) $10.0 million which was funded on November 18, 2016; (ii) $5.0 million may be drawn down by us at any time before the earlier of June 30, 2017 or an event of default, at our discretion, subject to achievement of certain financial and clinical milestones; and (iii) $5.0 million may be drawn down by us any time after June 30, 2017 and before the earlier of December 31, 2017 or an event of default, at our discretion, subject to achievement of certain milestones specified for the second tranche and additional financial and clinical milestones.

Net cash proceeds from borrowings

$ 9,736,000

5,000,000

Noncancelable operating lease expiration period

2017-05

Option to extend lease term

5 years

Noncancelable operating lease extension period

2019-05

Rent expense

$ 500,000

400,000

200,000

Convertible promissory note

$ 2,000,000

2,000,000

Accrued interest on convertible promissory note

$ 500,000

225,000

925,000

415,000

Sublease agreement, additional facility space, commenced period

2016-08

Sublease agreement, additional facility space, expiration period

2017-06

Research and development expenses

42,846,000

34,504,000

16,777,000

Research Funding and Option Agreement [Member] | The Scripps Research Institute [Member]

Debt Instrument [Line Items]

Agreement renewal period

12 months

Written notice period to terminate the agreement

30 days

Issue of common stock, shares in consideration for adjustment of sublicense payments | shares

119,840

Fair value of common stock issued

$ 1,400,000

Additional funding for research conducted

900,000

Research and development expenses

1,600,000

700,000

600,000

Research Funding and Option Agreement [Member] | National Foundation for Cancer Research [Member]

Debt Instrument [Line Items]

Charitable donations

400,000

400,000

$ 400,000

Master Services Agreement [Member] | FUJIFILM Diosynth Biotechnologies U.S.A., Inc. [Member]

Debt Instrument [Line Items]

Research and development expenses

$ 8,400,000

$ 5,100,000

Milestones payment terms

up to the mid seven figures.

Committed to pay based on development and production milestones

$ 600,000

Master Services Agreement [Member] | Stalaris Manufacturer [Member]

Debt Instrument [Line Items]

Research and development expenses

$ 1,000,000

Milestones payment terms

total payment in the low seven figures

Committed to pay based on development and production milestones

$ 2,200,000

Subsequent Event [Member]

Debt Instrument [Line Items]

Extended term of lease

2 years

Noncancelable operating lease extension period

2019-05

Maximum [Member] | The Scripps Research Institute [Member]

Debt Instrument [Line Items]

Obligation to pay an aggregate amount under agreement

$ 2,750,000

Silicon Valley Bank [Member]

Debt Instrument [Line Items]

Borrowings under loan and security agreement

$ 5,000,000

$ 5,000,000

Available credit under loan and security agreement

$ 10,000,000

Maturity date

Jun. 1, 2017

Debt instrument interest rate percentage

5.88%

5.00%

Additional debt instrument fee

500,000

Silicon Valley Bank and Solar Capital, Ltd. [Member]

Debt Instrument [Line Items]

Available credit under loan and security agreement

$ 20,000,000

Maturity date

Nov. 18, 2020

Repayment of debt, principal including accrued interest

$ 2,600,000

2,600,000

Debt instrument, final payment

$ 500,000

$ 500,000

Number of tranches | Tranche

3

Loan and security agreement, payment term

Pursuant to the Term Loan agreement, we have interest only payments through December 1, 2017 or June 1, 2018, if we draw the second tranche, followed by consecutive equal monthly payments of principal and interest in arrears through the maturity date of November 18, 2020.

Percentage of funded amount for final interest payment

8.75%

Non-usage fee percentage

2.00%

Net cash proceeds from borrowings

$ 7,300,000

Term loan effective interest rate

12.28%

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Prime Rate

Debt Instrument [Line Items]

Interest rate spread on variable rate

4.10%

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Tranche One [Member]

Debt Instrument [Line Items]

Available credit under loan and security agreement

$ 10,000,000

Loan and security agreement funded date

Nov. 18, 2016

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Tranche Two [Member] | Scenario, Forecast [Member]

Debt Instrument [Line Items]

Available credit under loan and security agreement

$ 5,000,000

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Tranche Three [Member] | Scenario, Forecast [Member]

Debt Instrument [Line Items]

Available credit under loan and security agreement

$ 5,000,000

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Minimum [Member]

Debt Instrument [Line Items]

Prepayment fee percentage

1.00%

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Minimum [Member] | Tranche Three [Member]

Debt Instrument [Line Items]

Loan and security agreement funded date

Jun. 30, 2017

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Maximum [Member]

Debt Instrument [Line Items]

Prepayment fee percentage

3.00%

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Maximum [Member] | Tranche Two [Member]

Debt Instrument [Line Items]

Loan and security agreement funded date

Jun. 30, 2017

Silicon Valley Bank and Solar Capital, Ltd. [Member] | Maximum [Member] | Tranche Three [Member]

Debt Instrument [Line Items]

Loan and security agreement funded date

Dec. 31, 2017

Subordinated Unsecured Convertible Promissory Note [Member]

Debt Instrument [Line Items]

Debt instrument interest rate percentage

8.00%

Convertible promissory note borrowed

$ 2,000,000

Debt, Commitments and Conting37

Debt, Commitments and Contingencies - Schedule of Future Principal Payments for Term Loan Including Final Payment (Detail) - Silicon Valley Bank and Solar Capital, Ltd. [Member] $ in Thousands	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
2,017	$ 249
2,018	3,100
2,019	3,348
2,020	4,178
Future principal payments for term loan including final payment, total	$ 10,875

Debt, Commitments and Conting38

Debt, Commitments and Contingencies - Schedule of Future Minimum Payments under Non-cancelable Operating Lease (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Leases Operating [Abstract]
2,017	$ 386
Operating Lease, total	$ 386

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)

1 Months Ended

3 Months Ended

12 Months Ended

15 Months Ended

Nov. 30, 2016

Sep. 30, 2016

Jan. 31, 2016

Oct. 31, 2015

Apr. 30, 2015

Dec. 31, 2014

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Sep. 30, 2015

Jan. 01, 2017

Jun. 13, 2016

Jan. 01, 2016

May 31, 2015

Dec. 31, 2013

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Common stock, shares authorized

150,000,000

95,500,000

Registration Statement filing date

Jun. 13, 2016

Number of common stock shares reserved for issuance

5,131,515

3,782,223

Stock options granted

2,266,419

Weighted average exercise price, granted

$ 5.56

Weighted average grant date fair value of options granted

$ 3.34

$ 11.29

$ 10.18

Aggregate intrinsic value of stock options exercised

$ 34,000

$ 1,900,000

$ 400,000

Unrecognized share based compensation expense related to unvested stock options and restricted stock units

$ 9,600,000

Unrecognized cost expected to be recognized over a weighted average period

2 years 10 months 24 days

Stock-based compensation

$ 5,029,000

4,856,000

1,791,000

SVB and Solar Loan and Security Agreement [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Exercise price of warrant per share

$ 3.14

Warrants expiration date

Nov. 18, 2023

Common Stock [Member] | SVB and Solar Loan and Security Agreement [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Warrants to purchase number of common stock, shares

47,771

Senior Vice President [Member] | Common Stock [Member] | Non-qualified Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options vesting period

4 years

Stock options granted

145,000

Weighted average exercise price, granted

$ 3.29

Employees and Consultants [Member] | Common Stock [Member] | Performance Options with Market Condition [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options vesting period

4 years

Stock options granted

169,402

Weighted average exercise price, granted

$ 10.24

Achievement of specified performance goals year and month

2017-10

Weighted average grant date fair value of options granted

$ 4.23

Requisite service period

4 years 9 months 18 days

Executives, Employees and Consultants [Member] | Common Stock [Member] | Performance Options with Market Condition [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options vesting period

4 years

Stock options granted

396,960

Weighted average exercise price, granted

$ 9.13

Weighted average grant date fair value of options granted

$ 1.93

Requisite service period

5 years 1 month 6 days

Achievement of specified performance goals

Jan. 4, 2018

Chief Executive Officer [Member] | Performance Options Without Market Condition [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Incremental share based compensation costs

$ 700,000

Share based compensation expense recognized

$ 600,000

One Year Anniversary [Member] | Senior Vice President [Member] | Common Stock [Member] | Non-qualified Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options vesting period

1 year

Option vesting percentage

25.00%

Monthly Basis Over Three Years [Member] | Senior Vice President [Member] | Common Stock [Member] | Non-qualified Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Options vesting period

3 years

Option vesting percentage

75.00%

2014 Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum term for stock option plan grant

10 years

Options vesting period

4 years

4 years

6 years

Stock options granted

931,749

Stock-based compensation

$ 800,000

2015 Stock Option and Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum term for stock option plan grant

10 years

Options vesting period

4 years

Options vesting period, description

monthly over the remaining three years

2015 Stock Option and Incentive Plan [Member] | One Year Anniversary [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Option vesting percentage

25.00%

2015 ESPP Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Number of common stock shares reserved for issuance

407,542

227,623

Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Amount of offering, issuance and sale covered in base prospectus

$ 150,000,000

Cowen Company, LLC (Cowen) [Member] | Sale Agreement [Member] | Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Amount of offering, issuance and sale covered in sales agreement prospectus

20,000,000

Agreed upon value of sale of common stock per transaction

$ 35,000,000

Redeemable Convertible Preferred Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Preferred stock, shares outstanding

73,487,415

73,487,415

73,487,415

IPO [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Common stock, shares authorized

150,000,000

IPO [Member] | 2015 Stock Option and Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Effective date of plan

May 6, 2015

Number of common stock shares reserved for issuance

1,574,566

Stock option grants description

The number of shares reserved and available for issuance under the 2015 Plan will automatically increase each January 1, beginning on January 1, 2016 and thereafter until January 1, 2019, by the lesser of (i) 1,840,000 shares, (ii) 4% of the outstanding number of shares of our common stock on the immediately preceding December 31 or (iii) an amount determined by our board of directors.

Percentage threshold of outstanding shares as of December 31 of each year for calculation of annual increase in authorized shares under the plan

4.00%

Additional number of common stock shares reserved for issuance

946,803

IPO [Member] | 2015 Stock Option and Incentive Plan [Member] | Subsequent Event [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Additional number of common stock shares reserved for issuance

949,793

IPO [Member] | 2015 ESPP Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Effective date of plan

May 6, 2015

Number of common stock shares reserved for issuance

227,623

Percentage threshold of outstanding shares as of December 31 of each year for calculation of annual increase in authorized shares under the plan

1.00%

Additional number of common stock shares reserved for issuance

236,700

IPO [Member] | 2015 ESPP Plan [Member] | Subsequent Event [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Additional number of common stock shares reserved for issuance

237,448

IPO [Member] | Maximum [Member] | 2015 Stock Option and Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Annual increase in shares authorized under plan, shares threshold

1,840,000

IPO [Member] | Redeemable Convertible Preferred Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Preferred stock, shares authorized

7,285,456

Preferred stock, shares issued

0

Preferred stock, shares outstanding

0

IPO [Member] | Undesignated Preferred Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Preferred stock, shares authorized

5,000,000

Preferred stock, shares issued

0

Preferred stock, shares outstanding

0

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Stock Option Activity (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Outstanding Options, Beginning Balance | shares	2,625,280
Number of Options, Granted | shares	2,266,419
Number of Options, Exercised | shares	(15,892)
Number of Options, Canceled/forfeited/expired | shares	(860,819)
Number of Outstanding Options, Ending Balance | shares	4,014,988
Number of Outstanding Options, Vested and Expected to Vest, Ending Balance | shares	4,014,988
Number of Outstanding Options, Exercisable, Ending Balance | shares	1,419,562
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 8.83
Weighted Average Exercise Price, Granted | $ / shares	5.56
Weighted Average Exercise Price, Exercised | $ / shares	1.24
Weighted Average Exercise Price, Canceled/forfeited/expired | $ / shares	10.17
Weighted Average Exercise Price, Ending Balance | $ / shares	6.73
Weighted Average Exercise Price, Options Vested and Expected to Vest, Ending Balance | $ / shares	6.73
Weighted Average Exercise Price, Options Exercisable, Ending Balance | $ / shares	$ 6.27
Weighted Average Contractual Term, Outstanding	7 years 9 months 26 days
Weighted Average Contractual Term, Options Vested and Expected to Vest	7 years 9 months 26 days
Weighted Average Contractual Term, Options Exercisable	5 years 10 months 17 days
Aggregate Intrinsic Value, Outstanding | $	$ 519
Aggregate Intrinsic Value, Options Vested and Expected to Vest | $	519
Aggregate Intrinsic Value, Options Exercisable | $	$ 519

Stockholders' Equity - Summar41

Stockholders' Equity - Summary of Assumptions Used to Determine Fair Value of Employee Stock Option Grants, Employee Stock Purchase Plan and Performance Options with Market Condition (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months	6 months
Risk-free interest rate		0.30%
Risk-free interest rate, minimum	0.40%
Risk-free interest rate, maximum	0.60%
Expected volatility		67.30%
Expected volatility, minimum	75.50%
Expected volatility, maximum	80.80%
Expected dividend yield	0.00%	0.00%
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	1.20%	1.50%	1.70%
Risk-free interest rate, maximum	2.10%	1.90%	2.70%
Expected volatility			111.00%
Expected volatility, minimum	80.70%	79.20%
Expected volatility, maximum	84.00%	100.90%
Expected dividend yield	0.00%	0.00%	0.00%
Employee Stock Option [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 6 months	5 years 6 months	5 years 9 months 7 days
Employee Stock Option [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 29 days	6 years 29 days	6 years 6 months 22 days
Performance Options with Market Condition [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 22 days	4 years 9 months 22 days
Risk-free interest rate	2.20%	2.10%
Expected volatility	83.30%	80.60%
Expected dividend yield	0.00%	0.00%

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Restricted Stock Unit Activity (Detail) - Restricted Stock Unit [Member]	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Number of Outstanding Restricted Stock Units, Granted | shares	131,593
Number of Outstanding Restricted Stock Units, Released | shares	(2,080)
Number of Outstanding Restricted Stock Units, Forfeited | shares	(52,800)
Number of Outstanding Restricted Stock Units, Ending Balance | shares	76,713
Weighted Average Grant Date Fair Value, Granted | $ / shares	$ 4.96
Weighted Average Grant Date Fair Value, Released | $ / shares	5.48
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	4.95
Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 4.95

Stockholders' Equity - Schedu43

Stockholders' Equity - Schedule of Allocation of Stock-Based Compensation for All Options Including Performance Options with Market Condition and Restricted Stock Units (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 5,029	$ 4,856	$ 1,791
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,876	2,524	527
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 3,153	$ 2,332	$ 1,264

Stockholders' Equity - Summar44

Stockholders' Equity - Summary of Warrants Outstanding (Detail)	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Class Of Warrant Or Right [Line Items]
Number Outstanding	121,512
Warrant One [Member]
Class Of Warrant Or Right [Line Items]
Number Outstanding	9,051
Exercise Price Per Share | $ / shares	$ 6.63
Expiration Date	2017-09
Warrant Two [Member]
Class Of Warrant Or Right [Line Items]
Number Outstanding	2,006
Exercise Price Per Share | $ / shares	$ 7.48
Expiration Date	2021-03
Warrant Three [Member]
Class Of Warrant Or Right [Line Items]
Number Outstanding	14,913
Exercise Price Per Share | $ / shares	$ 20.12
Expiration Date	2023-07
Warrant Four [Member]
Class Of Warrant Or Right [Line Items]
Number Outstanding	95,542
Exercise Price Per Share | $ / shares	$ 3.14
Expiration Date	2023-11

Stockholders' Equity - Summar45

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail) - shares	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	5,131,515	3,782,223
Common Stock Warrants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	121,512	25,970
Shares Available Under the 2015 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	510,760	903,350
Shares Available Under the 2015 ESPP Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	407,542	227,623
Common Stock Options and Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	4,091,701	2,625,280

Income Taxes - Schedule of Pret

Income Taxes - Schedule of Pretax Earnings (Loss) for Domestic and Foreign Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
United States	$ (57,096)	$ (47,490)	$ (34,885)
Foreign	(808)	(483)	10,535
Loss before income taxes	$ (57,904)	$ (47,973)	$ (24,350)

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliations of the Expected Statutory Federal Income Tax (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Expected income taxes benefit at federal statutory rate	$ (19,687)	$ (16,311)	$ (8,279)
State income taxes, net of federal benefit			(2,023)
Permanent items and other	675	865	368
Research credits	(6,800)	(2,674)	(372)
Unrecognized tax benefits	2,720	1,070	144
Foreign rate differential	141	84	(3,391)
Change in tax rate		3,551
Change in valuation allowance	22,902	$ 13,415	$ 13,553
Income tax (benefit) expense	$ (49)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Line Items]
Valuation allowance	$ 71,149,000	$ 48,319,000
Period of change in ownership	3 years
Percentage of change in ownership	50.00%
Unrecognized tax benefits, income tax penalties and interest accrued	$ 0	$ 0	$ 0
Change in unrecognized tax benefits	0
California [Member] | Operating Loss Carryforwards Expire in 2017 [Member]
Income Tax [Line Items]
Net operating loss carryforwards	$ 1,400,000
Net operating loss carryforwards expiration year	2,017
California [Member] | Operating Loss Carryforwards Expiring from 2028 through 2034 [Member]
Income Tax [Line Items]
Net operating loss carryforwards	$ 93,100,000
Minimum [Member] | California [Member] | Operating Loss Carryforwards Expiring from 2028 through 2034 [Member]
Income Tax [Line Items]
Net operating loss carryforwards expiration year	2,028
Maximum [Member] | California [Member] | Operating Loss Carryforwards Expiring from 2028 through 2034 [Member]
Income Tax [Line Items]
Net operating loss carryforwards expiration year	2,034
Federal [Member]
Income Tax [Line Items]
Net operating loss carryforwards	$ 87,800,000
Net operating loss carryforwards expiration year	2,025
Research and development credit carryforward	$ 2,800,000
Research and development credit carryforward expiration year	2,026
Federal [Member] | Orphan Drug Credits [Member]
Income Tax [Line Items]
Research and development credit carryforward	$ 11,000,000
Research and development credit carryforward expiration year	2,035
State [Member]
Income Tax [Line Items]
Net operating loss carryforwards	$ 94,500,000
Net operating loss carryforwards expiration year	2,016
Research and development credit carryforward	$ 2,500,000
Foreign [Member]
Income Tax [Line Items]
Net operating loss carryforwards	$ 6,500,000

Income Taxes - Schedule of Sign

Income Taxes - Schedule of Significant Components of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 33,713	$ 24,869
Capitalized research and development expenses	21,624	14,181
Research credits and other state credits	9,227	3,565
Intangible assets	3,874	4,176
Reserve and accruals	2,711	1,528
Valuation allowance	$ (71,149)	$ (48,319)

Income Taxes - Schedule of Acti

Income Taxes - Schedule of Activity Related to Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Balance as of beginning of year	$ 5,033	$ 1,106	$ 947
Increase related to prior year tax positions	1,890	2,404
Increase related to current year tax positions	6,077	1,523	177
Other decreases			(18)
Balance as of end of year	$ 13,000	$ 5,033	$ 1,106

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) - 401 (k) Plan [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Contribution Plan Disclosure [Line Items]
Policy approved month and year	2015-04
Date of Policy beginning	Jun. 1, 2015
Percentage of match employee contribution	50.00%
Percentage of participants's annual salary	6.00%
Discretionary contribution	$ 0.2	$ 0.1

Quarterly Financial Data (Una52

Quarterly Financial Data (Unaudited) - Schedule of Quarterly Data for Interim Periods (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Operating expenses	$ 12,527	$ 13,865	$ 15,433	$ 16,115	$ 16,483	$ 11,313	$ 10,898	$ 8,922	$ 57,940	$ 47,616	$ 23,554
Net loss	$ (12,566)	$ (13,819)	$ (15,383)	$ (16,087)	$ (16,493)	$ (11,329)	$ (11,080)	$ (9,071)	$ (57,855)	$ (47,973)	$ (24,350)
Basic and diluted net loss per share	$ (0.53)	$ (0.58)	$ (0.65)	$ (0.68)	$ (0.70)	$ (0.48)	$ (0.74)	$ (9.39)	$ (2.44)	$ (3.03)	$ (29.69)

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2016
Subsequent Event [Line Items]
Noncancelable operating lease extension period		2019-05
Subsequent Event [Member]
Subsequent Event [Line Items]
Noncancelable operating lease extension period	2019-05
Noncancelable operating lease additional commitment	$ 1.5