Kindred Biosciences (KIN) 10-K 4 Mar 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Feb. 29, 2016	Jun. 30, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	Kindred Biosciences, Inc.
Entity Central Index Key	1,561,743
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		19,836,360
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 78.6

Balance Sheets

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 19,992	$ 12,969
Short-term investments	53,051	88,058
Prepaid expenses and other	712	477
Total current assets	73,755	101,504
Property and equipment, net	1,244	394
Long-term investments	4,590	0
Other assets	30	22
Total assets	79,619	101,920
Current liabilities:
Accounts payable	717	420
Accrued compensation	1,922	1,457
Accrued liabilities	569	975
Total current liabilities	3,208	2,852
Long-term liability	40	44
Total liabilities	$ 3,248	$ 2,896
Commitments and contingencies (Note 10)
Stockholders’ equity:
Common stock; $0.0001 par value; 100,000,000 shares authorized; 19,836,360 shares and 19,724,482 shares issued and outstanding at December 31, 2015 and 2014, respectively	$ 2	$ 2
Additional paid-in capital	135,021	130,521
Accumulated other comprehensive loss	(50)	(27)
Accumulated deficit	(58,602)	(31,472)
Total stockholders’ equity	76,371	99,024
Total liabilities and stockholders’ equity	$ 79,619	$ 101,920

Balance Sheets (Parenthetical)

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	19,836,360	19,724,482
Common stock, shares outstanding	19,836,360	19,724,482

Statements of Operations and Co

Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating expenses:
Research and development	$ 4,579	$ 5,033	$ 4,991	$ 4,809	$ 4,802	$ 3,755	$ 5,639	$ 4,498	$ 19,412	$ 18,694	$ 3,140
General and administrative	1,881	2,095	1,921	1,953	2,014	2,342	2,504	1,679	7,850	8,539	1,079
Total operating expenses	6,460	7,128	6,912	6,762	6,816	6,097	8,143	6,177	27,262	27,233	4,219
Loss from operations	(6,460)	(7,128)	(6,912)	(6,762)	(6,816)	(6,097)	(8,143)	(6,177)	(27,262)	(27,233)	(4,219)
Interest and other income, net	40	33	29	30	27	25	33	9	132	94	6
Net loss	$ (6,420)	$ (7,095)	$ (6,883)	$ (6,732)	$ (6,789)	$ (6,072)	$ (8,110)	$ (6,168)	(27,130)	(27,139)	(4,213)
Change in unrealized gains or losses on available-for-sale securities									(23)	(27)	0
Comprehensive loss									$ (27,153)	$ (27,166)	$ (4,213)
Net loss per share, basic and diluted	$ (0.32)	$ (0.36)	$ (0.35)	$ (0.34)	$ (0.34)	$ (0.31)	$ (0.42)	$ (0.38)	$ (1.37)	$ (1.44)	$ (1.13)
Weighted-average number of common shares outstanding, basic and diluted	19,816	19,792	19,756	19,726	19,719	19,713	19,426	16,222	19,773	18,782	3,732

Statements of Changes in Conver

Statements of Changes in Convertible Preferred Stock and Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Series AA Preferred StockPreferred Stock	Series A-1 Preferred StockPreferred Stock	Series A-1A Preferred StockPreferred Stock
Beginning balance at Dec. 31, 2012	$ (120)	$ 0	$ 0	$ 0	$ (120)	$ 987	$ 0	$ 0
Beginning balance, shares at Dec. 31, 2012		3,000,000				1,000,000	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock	54,872	$ 1	54,871			$ 15	$ 5,843	$ 5,144
Issuance of stock, shares		8,625,000				15,000	1,850,000	1,650,000
Issuance of stock for services	12		12				$ 32	$ 78
Issuance of stock for services, in shares		5,000					10,000	25,000
Exercise of common stock options	$ 11		11
Exercise of common stock options, in shares	34,225	34,000
Conversion of Series AA, A-1 and A-1A preferred stock to common stock in connection with initial public offering	$ 12,099	$ 1	12,098			$ (1,002)	$ (5,875)	$ (5,222)
Conversion of Series AA, A-1 and A-1A preferred stock to common stock in connection with initial public offering, shares		4,550,000				(1,015,000)	(1,860,000)	(1,675,000)
Stock-based compensation	618		618
Net loss	(4,213)				(4,213)
Change in unrealized losses on available-for-sale securities	0
Total comprehensive loss	(4,213)
Ending balance at Dec. 31, 2013	63,279	$ 2	67,610	0	(4,333)	$ 0	$ 0	$ 0
Ending balance, shares at Dec. 31, 2013		16,214,000				0	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock	58,065		58,065
Issuance of stock, shares		3,450,000
Exercise of common stock options	$ 121		121
Exercise of common stock options, in shares	56,112	56,000
Stock-based compensation	$ 4,725		4,725
Net loss	(27,139)				(27,139)
Change in unrealized losses on available-for-sale securities	(27)			(27)
Total comprehensive loss	(27,166)
Vesting of restricted stock	0
Vesting of restricted stock, shares		4,000
Ending balance at Dec. 31, 2014	$ 99,024	$ 2	130,521	(27)	(31,472)	$ 0	$ 0	$ 0
Ending balance, shares at Dec. 31, 2014	19,724,482	19,724,000				0	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options	$ 105		105
Exercise of common stock options, in shares	58,126	58,000
Common stock issued under ESPP	$ 238		238
Common stock issued under ESPP, shares		53,752
Stock-based compensation	4,157		4,157
Net loss	(27,130)				(27,130)
Change in unrealized losses on available-for-sale securities	(23)			(23)
Total comprehensive loss	(27,153)
Ending balance at Dec. 31, 2015	$ 76,371	$ 2	$ 135,021	$ (50)	$ (58,602)	$ 0	$ 0	$ 0
Ending balance, shares at Dec. 31, 2015	19,836,360	19,836,000				0	0	0

Statements of Changes in Conve6

Statements of Changes in Convertible Preferred Stock and Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	1 Months Ended			2 Months Ended	12 Months Ended
	Apr. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Sep. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Preferred Stock | Series AA Preferred Stock
Payments of offering costs							$ 13
Preferred Stock | Series A-1 Preferred Stock
Payments of offering costs			$ 22			$ 22
Preferred Stock | Series A-1A Preferred Stock
Payments of offering costs				$ 88		88
Common Stock
Payments of offering costs	$ 4,035	$ 5,504			$ 4,035	$ 5,504

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash Flows from Operating Activities
Net loss	$ (27,130)	$ (27,139)	$ (4,213)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	4,157	4,422	922
Depreciation and amortization expense	146	58	3
Amortization of premium on marketable securities	228	87	0
Changes in operating assets and liabilities:
Prepaid expenses and other	(235)	(329)	(147)
Other assets	(8)	(22)	0
Accounts payable	30	(269)	683
Due to related party	0	0	(5)
Accrued liabilities and accrued compensation	55	1,258	1,184
Net cash used in operating activities	(22,757)	(21,934)	(1,573)
Cash Flows from Investing Activities
Purchase of investments	(102,195)	(145,172)	0
Sale of investments	3,000	9,000	0
Maturities of investments	129,361	48,000	0
Purchase of property and equipment	(729)	(440)	(15)
Net cash provided by (used in) investing activities	29,437	(88,612)	(15)
Cash Flows from Financing Activities
Exercise of stock options and purchase of ESPP shares	343	121	11
Net proceeds from initial public offering	0	0	54,871
Net proceeds from follow-on public offering	0	58,065	0
Net cash provided by financing activities	343	58,186	65,979
Net change in cash and cash equivalents	7,023	(52,360)	64,391
Cash and cash equivalents at beginning of year	12,969	65,329	938
Cash and cash equivalents at end of year	19,992	12,969	65,329
Supplemental disclosure of non-cash financing activities:
Issuance of common stock and stock options for accrued consulting expenses			12
Conversion of Series AA, Series A-1 and Series A-1A preferred stock into shares of common stock	0	0	12,099
Purchase of property and equipment included in accounts payable and accrued liabilities	0	0	0
Series AA Preferred Stock
Supplemental disclosure of non-cash financing activities:
Issuance of convertible stock for settlement of offering costs and other legal fees	0	0	15
Series A-1 Preferred Stock
Cash Flows from Financing Activities
Proceeds from issuance of Series A convertible preferred stock	0	0	5,865
Supplemental disclosure of non-cash financing activities:
Issuance of convertible stock for settlement of offering costs and other legal fees	0	0	32
Series A-1A Preferred Stock
Cash Flows from Financing Activities
Proceeds from issuance of Series A convertible preferred stock	0	0	5,232
Supplemental disclosure of non-cash financing activities:
Issuance of convertible stock for settlement of offering costs and other legal fees	0	0	78
Common Stock
Supplemental disclosure of non-cash financing activities:
Issuance of common stock and stock options for accrued consulting expenses	$ 0	$ 303	$ 535

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Kindred Biosciences, Inc. (“we”, "us" or "our") was incorporated on September 25, 2012 (inception) in the State of Delaware. We are a biopharmaceutical company focused on saving and improving the lives of pets. Our activities since inception have consisted principally of raising capital, establishing facilities, recruiting management and technical staff and performing research and development and advancing our product candidates seeking regulatory approval. Our headquarters are in Burlingame, California. We are subject to risks common to companies in the biotechnology and pharmaceutical industries. There can be no assurance that our research and development will be successfully completed, that adequate protection for our technology will be obtained, that any products developed will obtain necessary government regulatory approval or that any approved products will be commercially viable. We operate in an environment of substantial competition from other animal health companies. In addition, we are dependent upon the services of our employees and consultants, as well as third-party contract research organizations and manufacturers. Liquidity We have incurred losses and negative cash flows from operations and have not generated any revenue since our inception and had an accumulated deficit of $58,602,000 as of December 31, 2015. We expect to continue to incur losses and negative cash flows, which will increase significantly from historical levels as we expand our product development activities, seek regulatory approvals for our product candidates, establish a biologics manufacturing capability, and begin to commercialize any approved products. To date, we have been funded primarily through sales of convertible preferred stock, the sale of our common stock in our initial public offering in December 2013 and the sale of our common stock in a follow-on public offering in April 2014. We might require additional capital until such time as we can generate operating revenues in excess of operating expenses. We believe our cash, cash equivalents, short-term and long-term investments of $77,633,000 at December 31, 2015 are sufficient to fund our operations for at least the next 24 months. If we require additional funding for operations, we may seek such funding through public or private equity or debt financings or other sources, such as corporate collaborations and licensing arrangements. We may not be able to obtain financing on acceptable terms, or at all, and we may not be able to enter into corporate collaborations or licensing arrangements. The terms of any financing may result in dilution or otherwise adversely affect the holdings or the rights of our stockholders. If we are unable to obtain funding, we could be forced to delay, reduce or eliminate our research and development programs or commercialization efforts, which could adversely affect our business prospects.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). Use of Estimates The preparation of financial statements and related disclosures in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the valuation of common stock and stock-based awards, the realization of deferred tax assets, the recoverability of long-lived assets and the accrual of research and development expenses. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from those estimates. Cash, Cash Equivalents and Investments We consider all highly liquid investments purchased with an original maturity of three months or less at the date of acquisition to be cash equivalents. Debt securities with original maturities greater than three months and remaining maturities less than one year are classified as short-term investments. We classify all investments as available-for-sale. Available-for-sale securities are carried at estimated fair value, with accumulated unrealized gains and losses reported as a component of accumulated other comprehensive income (loss) in the accompanying balance sheets. Realized gains or losses on the sale of investments are determined on a specific identification method, and such gains and losses are reflected as a component of interest and other income, net in the accompanying statements of operations and comprehensive loss. Marketable securities investments are evaluated periodically for impairment. We take into account general market conditions, changes in the economic environment as well as specific investment attributes, such as credit downgrade or illiquidity for each investment, the expected cash flows from the securities, our intent to sell the securities and whether or not we will be required to sell the securities before the recovery of their amortized cost, to estimate the fair value of our investments and to determine whether impairment is other than temporary. If it is determined that a decline in fair value of any investment is other than temporary, then the unrealized loss related to credit risk would be included in interest and other income, net. Concentration of Credit Risk and of Significant Suppliers Our financial instrument that potentially subjects us to concentrations of credit risk is cash and cash equivalents. From time to time, we maintain cash balances in excess of amounts insured by the Federal Deposit Insurance Corporation (“FDIC”). Primarily all of our cash and cash equivalents at December 31, 2015 were in excess of amounts insured by the FDIC. We do not believe that we are subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. We are dependent on third-party manufacturers to supply products for research and development activities in our programs. In particular, we rely on a small number of manufacturers to supply us with our requirements for the active pharmaceutical ingredients, or API, and formulated drugs related to some of these programs. These programs would be adversely affected by a significant interruption in the supply of API. Fair Value Measurements We use the provisions of Accounting Standards Codification ("ASC") 820, “Fair Value Measurements and Disclosure" , to determine the fair values of our financial and nonfinancial assets and liabilities where applicable. ASC 820 defines fair value, establishes a framework for measuring fair value in U.S. GAAP and expands disclosure about fair value measurements. The objective of fair value measurement is to determine the price that would be received to sell the asset or paid to transfer the liability (an exit price) in an orderly transaction between market participants at the measurement date. ASC 820 emphasizes that fair value is a market-based measurement, not an entity-specific measurement, and that market participant assumptions include assumptions about risk and effect of a restriction on the sale or use of an asset. To increase consistency and comparability in fair value measurement and related disclosures, ASC 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels: (1) Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date; (2) Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly through corroboration with observable market data; and (3) Level 3 inputs are unobservable inputs for the asset or liability that reflect the reporting entity’s own assumptions about risk and the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. Government agency securities are recorded at their estimated fair value. Since these government securities generally have market prices from multiple sources and it can be difficult to select the best individual price directly from the quoted prices in the active markets, we use Level 2 inputs for the valuation of these securities. Using the Level 2 inputs, a “consensus price” or a weighted average price for each of these securities can be derived from a distribution-curve-based algorithm which includes market prices obtained from a variety of industrial standard data providers (e.g. Bloomberg), security master files from large financial institutions, and other third-party sources. The carrying amount of financial instruments, including cash, accounts payable and accrued liabilities approximate fair value due to the short maturities of these financial instruments. Financial assets, which consist of money market funds and available-for-sale securities, are measured at fair value on a recurring basis (see Note 3). Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. We calculate depreciation using the straight-line method over the estimated useful lives of the assets, which range from two to five years. Expenditures for repairs and maintenance of assets are charged to expense as incurred. We amortize leasehold improvements using the straight-line method over the estimated useful lives of the respective assets or the lease term, whichever is shorter. Upon retirement or sale, the cost and related accumulated depreciation and amortization of assets disposed of are removed from the accounts and any resulting gain or loss is included in other income/expense. Licenses The costs incurred for the rights to use licensed technologies in the research and development process, including licensing fees and milestone payments, are charged to research and development expense as incurred in situations where we have not identified an alternative future use for the acquired rights, and are capitalized in situations where we have identified an alternative future use. No costs associated with the use of licensed technologies have been capitalized to date. Impairment of Long-Lived Assets We review long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that we consider in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, we compare forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, we have not recorded any impairment losses on long-lived assets. Revenue Recognition We are in the research and development stage and have not generated any revenues since inception. Research and Development Costs All costs of research and development are expensed in the period incurred. Research and development costs primarily consist of salaries and related expenses for personnel, stock-based compensation expense, fees paid to consultants, outside service providers, professional services, travel costs and materials used in clinical trials and research and development. Patent Costs All patent-related costs incurred in connection with filing patent applications are recorded in research and development expenses when incurred, as recoverability of such expenditures is uncertain. Stock-Based Compensation Our stock-based compensation plan (see Note 9) provides for the grant of stock options, restricted common stock and stock appreciation rights. The estimated fair values of stock option grants are determined as of the date of grant using the Black-Scholes option pricing model. This method incorporates the fair value of our common stock at the date of each grant and various assumptions such as the risk-free interest rate, expected volatility based on the historic volatility of publicly-traded peer companies, expected dividend yield, and expected term of the options. The estimated fair values of restricted stock awards are determined based on the fair value of our common stock on the date of grant. The estimated fair values of stock-based awards, including the effect of estimated forfeitures, are expensed over the requisite service period, which is generally the awards’ vesting period. We classify stock-based compensation expense in the statement of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified. Our accounting policy for equity instruments issued to consultants and vendors in exchange for goods and services follows Financial Accounting Standards Board ("FASB") guidance. All transactions in which goods or services are the consideration received for the issuance of equity instruments are accounted for based on the fair value of the consideration received or the fair value of the equity instrument issued, whichever is more reliably measurable. The measurement date of the fair value of the equity instrument issued is the earlier of the date on which the counterparty’s performance is complete or the date at which a commitment for performance is reached. For transactions in which the fair value of the equity instrument issued to non-employees is the more reliable measurement and a measurement date has not been reached, the fair value is re-measured at each reporting date using the Black-Scholes option pricing model. Compensation expense for these share-based awards is recognized over the term of the consulting agreement or until the award is approved and settled. Income Taxes We account for income taxes using 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 recognized in the financial statements or in our tax returns. Deferred taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. We assess the likelihood that our deferred tax assets will be recovered from future taxable income and, to the extent we believe, based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. We account for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. Comprehensive Loss Our comprehensive loss includes the change in unrealized gains or losses on available-for-sale securities. The cumulative amount of gains or losses is reflected as a separate component of stockholders' equity in the accompanying balance sheets as accumulated other comprehensive loss. Segment Data We manage our operations as a single segment for the purposes of assessing performance and making operating decisions. We are a veterinary biotechnology company focusing on developing therapies for pets. Our chief operating decision maker is our Chief Executive Officer. All assets are held in the United States. Basic and Diluted Net Loss Per Common Share Basic net loss per common share is computed by dividing net loss attributable to common stockholders for the period by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders for the period by the weighted average number of common shares, including potential dilutive shares of common stock assuming the dilutive effect of potentially dilutive securities. For periods in which we have reported a net loss, diluted net loss per common share is the same as basic net loss per common share, since the impact of the potentially dilutive securities would be anti-dilutive to the calculation of net loss per common share (see Note 13). Recently Issued 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" , which provides guidance regarding management’s responsibility to assess whether substantial doubt exists regarding the ability to continue as a going concern and to provide related footnote disclosures. In connection with preparing financial statements for each annual and interim reporting period, management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the company’s ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). Our adoption of this standard did not have any material impact on our financial statements. In November 2015, the FASB issued ASU No. 2015-17, "Balance Sheet Classification of Deferred Taxes" , requiring all deferred tax assets and liabilities, and any related valuation allowance, to be classified as non-current on the balance sheet. The classification change for all deferred taxes as non-current simplifies entities’ processes as it eliminates the need to separately identify the net current and net non-current deferred tax asset or liability in each jurisdiction and allocate valuation allowances. The update is effective for public business entities issuing financial statements for the annual periods beginning after December 15, 2016, and interim periods within those annual periods. We are currently evaluating the new guidance and have not determined the impact this standard may have on our financial statements. In January 2016, the FASB issued ASU No. 2016-01, "Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities" , which amends the guidance in U.S. GAAP on the classification and measurement of financial instruments and also amends certain disclosure requirements associated with the fair value of financial instruments. The new guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We are currently evaluating the new guidance and have not determined the impact this standard may have on our financial statements. In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" , requiring organizations that lease assets—referred to as “lessees”—to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. The ASU on leases will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We are currently evaluating the new guidance and have not determined the impact this standard may have on our financial statements. We do not believe there are any other recently issued standards not yet effective that will have a material impact on our financial statements when the standards become effective.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements We measure certain financial assets at fair value on a recurring basis, including cash equivalents and available-for-sale securities. The fair value of these financial assets was determined based on a three-tier fair value hierarchy as described in Note 2, which prioritizes the inputs used in measuring fair value. The following table presents information about our financial assets that are measured at fair value on a recurring basis as of December 31, 2015 and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value: (In thousands) Fair Value Measurements as of December 31, 2015 Description Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Cash equivalents: Money market funds $ 8,169 $ 8,169 $ — $ — U.S. government agency notes 4,385 — 4,385 — Short-term investments: U.S. treasury bills 41,282 — 41,282 — U.S. government agency notes 11,769 — 11,769 — Long-term investments: U.S. treasury bills 4,590 — 4,590 — $ 70,195 $ 8,169 $ 62,026 $ — The following table presents information about our financial assets that are measured at fair value on a recurring basis as of December 31, 2014 and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value: (In thousands) Fair Value Measurements as of December 31, 2014 Description Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Cash equivalents: Money market funds $ 834 $ 834 $ — $ — Short-term investments: U.S. treasury bills 5,998 — 5,998 — U.S. government agency notes 82,060 — 82,060 — $ 88,892 $ 834 $ 88,058 $ — There were no transfers of assets between Level 1, Level 2 or Level 3 of the fair value hierarchy at December 31, 2015 and 2014 . At December 31, 2015 and 2014 , we did not have any financial liabilities which were measured at fair value on a recurring basis.

Investments

Investments	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Short-term Investments	Investments The following tables summarize our investments in available-for-sale securities by significant investment category reported as short-term or long-term investments as of December 31, 2015 and 2014 (in thousands): December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term investments: U.S. treasury bills $ 41,293 $ 14 $ (25 ) $ 41,282 U.S. government agency notes 11,776 — (7 ) 11,769 U.S. treasury bonds and notes 25 9 (34 ) — 53,094 23 (66 ) 53,051 Long-term investments: U.S. treasury bills 4,597 — (7 ) 4,590 Total available-for-sale investments $ 57,691 $ 23 $ (73 ) $ 57,641 December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term investments: U.S. treasury bills $ 5,994 $ 4 $ — $ 5,998 U.S. treasury bonds and notes 82,091 — (31 ) 82,060 Total available-for-sale investments $ 88,085 $ 4 $ (31 ) $ 88,058 The following table summarizes the contractual maturities of our available-for-sale securities at December 31, 2015 (in thousands): Amortized Cost Fair Value Mature in less than one year $ 53,094 $ 53,051 Mature in one year or more $ 4,597 $ 4,590

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment, Net [Abstract]
Property and Equipment, Net	Property and Equipment, Net Property and equipment consisted of the following: As of December 31, (in thousands) 2015 2014 Computer and lab equipment $ 437 $ 359 Furniture & fixtures 38 24 Leasehold improvements 78 69 Construction-in-process 895 — Total 1,448 452 Less accumulated depreciation and amortization (204 ) (58) Property and equipment, net $ 1,244 $ 394 Depreciation and amortization expense was $146,000 , $58,000 and $3,000 for the years ended December 31, 2015 , 2014 and 2013, respectively.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consisted of the following as of December 31, 2015 and 2014 : (In thousands) December 31, 2015 December 31, 2014 Accrued consulting $ 83 $ — Accrued research and development costs 345 715 Accrued other 128 247 Deferred rent 53 57 609 1,019 Less current portion (569 ) (975 ) Long-term liability (deferred rent) $ 40 $ 44

Convertible Preferred Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Convertible Preferred Stock	Convertible Preferred Stock Prior to our initial public offering in December 2013, our Certificate of Incorporation, as amended and restated, authorized us to issue 15,000,000 shares of $0.0001 par value preferred stock. Through December 16, 2013, we had issued 1,015,000 shares of Series AA convertible preferred stock (“Series AA Preferred Stock”), 1,860,204 shares of Series A-1 convertible preferred stock (“Series A-1 Preferred Stock") and 1,675,002 shares of Series A-1A convertible preferred stock (“Series A-1A Preferred Stock") (collectively, the “Preferred Stock”). In connection with our initial public offering in December 2013, all outstanding shares of the Preferred Stock automatically converted into 4,550,195 (net of an adjustment for 11 fractional shares) shares of our common stock. In November 2013, we issued 15,000 shares of Series AA Preferred Stock for payment of accrued offering costs. In connection with the Series AA Preferred Stock offering, each holder of at least 10,000 shares of Series AA Preferred Stock or shares of our common stock issued upon conversion of the Series AA Preferred Stock was granted the right of first refusal to purchase his pro rata share of new securities (any capital stock, including common stock and preferred stock, convertible securities, options or warrants to purchase capital stock) which we may, from time to time, propose to sell and issue. Certain securities transactions were excluded from this right as provided in the Series AA Investors’ Rights Agreement. In June 2013, we commenced an offering for the sale and issuance of up to 2,000,000 shares of Series A-1 Preferred Stock at an issuance price equal to $3.17 per share. During June through September 2013, we received gross proceeds of $5,865,000 related to the issuance of 1,850,204 shares of the Series A-1 Preferred Stock. In connection with the Series A-1 Preferred Stock financing, we incurred offering costs of $22,000 which were recorded as a reduction of the gross proceeds. In June 2013, we issued 5,000 shares of the Series A-1 Preferred Stock valued at $16,000 on the date of issuance for partial payment of the Series A-1 Preferred Stock offering costs. In August 2013, we issued an additional 5,000 shares of the Series A-1 Preferred Stock valued at $16,000 on the date of issuance for payment of the remaining Series A-1 Preferred Stock offering costs and other legal fees. In connection with the sale and issuance of the Series A-1 Preferred Stock, the holders of the Series AA Preferred Stock waived their right of first refusal under the Series AA Investors’ Rights Agreement with respect to any sale by us of a proposed future series of preferred stock (“Series A-2 Preferred Stock”) on or before June 30, 2014. Additionally, each holder of at least 10,000 shares of Series A-1 Preferred Stock or shares of our common stock issued upon conversion of the Series A-1 Preferred Stock was granted the right of first refusal to purchase his pro rata share of new securities (any capital stock, including common stock and preferred stock, convertible securities, options or warrants to purchase capital stock) which we may, from time to time, propose to sell and issue. Certain securities transactions were excluded from this right as provided in the Series A-1 Investors’ Rights Agreement. Pursuant to the terms of the Series A-1 Preferred Stock Purchase Agreement, if shares of the Series A-2 Preferred Stock were issued prior to June 30, 2014, and the rights, preferences, or privileges of the Series A-2 Preferred Stock were more favorable to the holders of those shares than the terms of the Series A-1 Preferred Stock, then the rights, preferences and privileges of the Series A-1 Preferred Stock would be amended to be substantially the same of those of the Series A-2 Preferred Stock. In addition, if shares of the Series A-2 Preferred Stock were issued prior to June 30, 2014 and the purchase price of the Series A-2 Preferred Stock was such that the purchase price of the Series A-1 Preferred Stock was not at least 10% lower than the purchase price of the Series A-2 Preferred Stock, then additional shares of Series A-1 Preferred Stock would be issued to the Series A-1 Preferred Stockholders so that the effective price of the Series A-1 Preferred Stock was at least 10% lower than Series A-2 Preferred Stock. We determined that the value of these embedded derivative features was not significant. Prior to the automatic conversion of the Series A-1 Preferred Stock in December 2013 in connection with our initial public offering, no shares of Series A-2 Preferred Stock were authorized by us. In August 2013, we commenced an offering for the sale and issuance of up to 2,000,000 shares of Series A-1A Preferred Stock at an issuance price equal to $3.17 per share. In August and September 2013, we received gross proceeds of $5,232,000 related to the issuance of 1,650,396 shares of the Series A-1A Preferred Stock. In connection with the Series A-1A Preferred Stock financing, we incurred offering costs of $88,000 which were recorded as a reduction of the gross proceeds. In August 2013, we issued 24,606 shares of the Series A-1A Preferred Stock valued at $78,000 on the date of issuance for payment of certain Series A-1A offering costs. In connection with the Series A-1A Preferred Stock offering, each holder of at least 10,000 shares of Series A-1A Preferred Stock or shares of our common stock issued upon conversion of the Series A-1A Preferred Stock was granted the right of first refusal to purchase his pro rata share of new securities (any capital stock, including common stock and preferred stock, convertible securities, options or warrants to purchase capital stock) which we may, from time to time, propose to sell and issue. Certain securities transactions were excluded from this right as provided in the Series A-1A Investors’ Rights Agreement. In addition, holders of the Series A-1A Preferred Stock waived their right of first refusal under the Series A-1A Investors’ Rights Agreement with respect to any sale by us of Series A-2 Preferred Stock on or before June 30, 2014. Pursuant to the terms of the Series A-1A Preferred Stock Purchase Agreement, if shares of the Series A-2 Preferred Stock were issued prior to June 30, 2014, and the rights, preferences, or privileges of the Series A-2 Preferred Stock were more favorable to the holders of those shares than the terms of the Series A-1A Preferred Stock, then the rights, preferences and privileges of the Series A-1A Preferred Stock would be amended to be substantially the same of those of the Series A-2 Preferred Stock. In addition, if shares of the Series A-2 Preferred Stock were issued prior to June 30, 2014 and the purchase price of the Series A-2 Preferred Stock was such that the purchase price of the Series A-1A Preferred Stock was not at least 10% lower than the purchase price of the Series A-2 Preferred Stock, then additional shares of Series A-1A Preferred Stock would be issued to the Series A-1A Preferred Stockholders so that the effective price of the Series A-1A Preferred Stock was at least 10% lower than Series A-2 Preferred Stock. We determined that the value of these embedded derivative features was not significant. Prior to the automatic conversion of the Series A-1A Preferred Stock in December 2013 in connection with our initial public offering, no shares of Series A-2 Preferred Stock were authorized by us. The holders of the Preferred Stock had the following rights and preferences: Voting Rights Except as otherwise provided in our Certificate of Incorporation, as amended and restated, or as required by law, holders of the Preferred Stock shall vote together and not as a separate class. Each holder of the Preferred Stock shall be entitled to the number of votes equal to the number of shares of common stock into which the shares of the Preferred Stock held by such holder could be converted as of the record date. The holders of shares of the Preferred Stock shall be entitled to vote on all matters on which the common stock shall be entitled to vote. Holders of the Preferred Stock shall be entitled to notice of any stockholders’ meeting in accordance with our Bylaws. Fractional votes shall not, however, be permitted and any fractional voting rights resulting from the above formula (after aggregating all shares into which shares of Preferred Stock held by each holder could be converted), shall be disregarded. Liquidation Preference In the event of any liquidation, dissolution or winding up of our company, either voluntary or involuntary, the holder of the Preferred Stock shall be entitled to receive, prior and in preference to any distribution of any of our assets to the holders of the common stock by reason of their ownership of such stock, an amount per share equal to $1 per share for the Series AA Preferred Stock and $3.17 per share for the Series A-1 Preferred Stock and Series A-1A Preferred Stock, or such lesser amount as may be approved by the holders of the majority of the outstanding shares of the Preferred Stock. If upon liquidation, dissolution or winding up of our company, our assets legally available for distribution to the holders of the Preferred Stock are insufficient to permit the payment in full of the liquidation preference above, then our entire assets legally available for distribution shall be distributed with equal priority and pro rata among the holders of the Preferred Stock in proportion to the full amounts they would otherwise be entitled to receive. After the payment or setting aside for payment to the holders of Preferred Stock of the full amounts of the liquidation preferences, our entire remaining assets legally available for distribution shall be distributed pro rata to holders of our common stock in proportion to the number of shares of common stock held by them. Conversion Rights Optional Conversion The shares of Preferred Stock are convertible into shares of common stock, at the option of the holder, at any time after the date of issuance. Each share of Preferred Stock will be converted into shares of common stock at the applicable Series AA, Series A-1 and Series A-1A Preferred Stock conversion rate then in effect, which is calculated by dividing the original issue price by the respective conversion price. The conversion prices for the Series AA, Series A-1 and Series A-1A Preferred Stock are equal to $1.00 per share, $3.17 per share and $3.17 per share, respectively, and are subject to adjustment as set forth in our Certificate of Incorporation, as amended and restated. In connection with our initial public offering in December 2013, all outstanding shares of the Series AA, Series A-1 and Series A-1A Preferred Stock were converted into shares of common stock on a 1 -for-1 basis. Automatic Conversion Each share of Preferred Stock automatically converted into shares of common stock upon us becoming a public company in connection with our initial public offering. Redemption Rights There were no redemption rights afforded the holders of Preferred Stock. Upon certain change in control events that were outside of our control, including liquidation, sale or transfer of control of our company, holders of the Preferred Stock could cause its redemption. Therefore, prior to the automatic conversion of the Preferred Stock in connection with our initial public offering in December 2013, the Preferred Stock was classified outside of stockholders’ equity in accordance with authoritative guidance for the classification and measurement of potentially redeemable securities. Reissuance All shares of Preferred Stock that were converted into common stock were canceled and will not be reissued by us. In December 2013, we amended our Certificate of Incorporation to authorize the issuance of 10,000,000 shares of $0.0001 par value preferred stock. At December 31, 2015 , all shares of preferred stock are undesignated and unissued.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Common Stock	Common Stock Our Certificate of Incorporation, as amended and restated, authorizes us to issue 100,000,000 shares of $0.0001 par value common stock. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of our stockholders, provided, however, that, except as otherwise required by law, holders of common stock shall not be entitled to vote on any amendment to the Certificate of Incorporation that relates solely to the terms of one or more outstanding shares of preferred stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other series, to vote thereon pursuant to the Certificate of Incorporation or pursuant to the Delaware General Corporation Law. In August 2013, we issued 5,200 shares of restricted common stock at a price of $2.27 per share to a consultant for services rendered and recorded stock-based compensation expense of $12,000 . In 2013, we issued 34,225 shares of common stock upon exercise of stock options at a price of $0.32 per share for total proceeds of $11,000 . In December 2013, we completed an initial public offering and issued 8,625,000 shares of common stock at $7.00 per share resulting in net proceeds of $54,871,000 after deduction of underwriting commissions and offering expenses of $5,504,000 . In April 2014, we completed a follow-on public offering and issued 3,450,000 shares of common stock at $18.00 per share resulting in net proceeds of $58,065,000 after deduction of underwriting commissions and offering expenses of $4,035,000 . In 2014, we issued 56,112 shares of common stock upon exercise of stock options at prices ranging from $0.32 to $15.41 per share for total proceeds of $121,000 . In 2014, we issued 3,750 shares of restricted common stock to a consultant for services rendered and recorded stock-based compensation expense of $61,000 . In 2015, we issued 58,126 shares of common stock upon exercise of stock options at prices ranging from $0.32 to $3.83 per share for total proceeds of $105,000 . In addition, we issued 53,752 shares of common stock to employees in connection with our employee stock purchase program for total proceeds of $238,000 . As of December 31, 2015 , we had 19,836,360 shares of common stock outstanding.

Stock-Based Awards

Stock-Based Awards	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Awards	Stock-Based Awards and Benefit Plan On November 4, 2012, our board of directors adopted the Kindred Biosciences, Inc. 2012 Equity Incentive Plan (the “2012 Plan”). The 2012 Plan provides for our board of directors to grant incentive stock options or non-qualified stock options for the purchase of common stock, to issue or sell shares of restricted common stock and to grant stock appreciation rights (“SARs”) to our employees, directors, consultants and advisers of the Company. Pursuant to the terms of the 2012 Plan, no options or SARs shall be granted under the 2012 Plan after 10 years from the date of adoption of the 2012 Plan. We have reserved 4,000,000 shares of our common stock for issuance under the 2012 Plan. Retrospective Reassessment of the Fair Value of Common Stock As required by the 2012 Plan, the exercise price for awards granted is not to be less than the fair market value of our common stock as of the date of grant. We value shares of common stock by taking into consideration our most recently available valuation of common stock performed by management and the board of directors, as well as additional factors which may have changed since the date of the most recent contemporaneous valuations through the date of grant. On February 4, 2013, May 9, 2013, August 29, 2013 and September 12, 2013, the board of directors granted stock options for the purchase of 576,525 shares, 154,793 shares, 412,580 shares, and 29,000 shares, respectively, of our common stock with weighted-average exercise prices of $0.35 per share, $0.32 per share, $0.90 per share and $0.90 per share, respectively. On November 11, 2013, our board of directors, with the consent of the affected employee and director option holders, approved an increase from $0.90 per share to $1.37 per share in the exercise price of 285,092 employee and director options granted in August and September 2013. The fair value of our common stock on the February 4, 2013 and May 9, 2013 grant dates was $0.32 per share, and on the August 29, 2013 and September 12, 2013 grant dates was $1.37 per share, as determined by our board of directors. In connection with the December 2013 initial public offering of our common stock, we reexamined, for financial reporting purposes only, the fair value of our common stock. In connection with the reexamination, we determined that retrospective valuations of the fair value of common stock as of February 4, 2013, May 9, 2013, August 29, 2013 and September 12, 2013 were appropriate due to acceleration of the timeframe to a potential liquidity event and the proposed initial public offering, which had not been contemplated in the determination of the original fair values on these dates. Based on this analysis, the fair value of common stock remained unchanged for the February 4, 2013 and May 9, 2013 grant dates. Based on this analysis, the fair value of the common stock on the August 29, 2013 and September 12, 2013 grant dates was determined to be $2.27 per share, which we used to value the stock-based compensation expense for these awards. Stock Options Our board of directors determines the exercise price and vesting period of all stock options. The exercise price of the stock options will be no less than 100% of the fair value per share of our common stock on the grant date. If a person owns capital stock representing more than 10% of all classes of our stock, the exercise price will be not less than 110% of the fair market value on the date of grant. Options are vested over variable periods, generally ranging from one to four years, and expire not more than 10 years after the date of grant. As of December 31, 2015 , there were 3,116,185 option shares outstanding and 726,402 shares available for future grants under the 2012 Plan. During the years ended December 31, 2015 and 2014, we granted under the 2012 Plan stock options for the purchase of 922,083 and 1,127,113 shares of common stock, respectively, to employees, non-employee consultants and directors. 2014 Employee Stock Purchase Plan In December 2014, our board of directors adopted the Kindred Biosciences, Inc. 2014 Employee Stock Purchase Plan (the “Purchase Plan”). A total of 200,000 shares of our common stock are authorized for issuance under the Purchase Plan. The Purchase Plan permits eligible employees to purchase common stock at a discount through payroll deductions during defined six months consecutive offering periods beginning on December 1 with the exception of our first offering period which commenced on January 1, 2015 for a five months duration. The price at which the stock is purchased is equal to the lower of 85% of the fair market value of the common stock on the first day of the offering or 85% of the fair market value of our common stock on the purchase date. A participant may purchase a maximum of 2,000 shares of common stock during each offering period, not to exceed $25,000 worth of common stock on the offering date during each calendar year. We use the Black-Scholes option pricing model, in combination with discounted employee price, in determining the value of the Purchase Plan expense to be recognized during each offering period. The weighted-average grant date fair value per share using the Black-Scholes option pricing model was $2.08 during the year ended December 31, 2015. As of December 31, 2015, there were 53,752 shares of common stock issued under the Purchase Plan and 146,248 shares available for future issuance under the Purchase Plan. At December 31, 2015, we had an outstanding liability of $25,000 , which is included in accrued compensation on the balance sheet, for employee contributions to the Purchase Plan for shares pending issuance at the end of the next offering period. Reserved Shares At December 31, 2015, shares of common stock reserved for future issuance inclusive of outstanding option shares are as follows: 2012 Equity Incentive Plan 3,842,587 2014 Employee Stock Purchase Plan 146,248 3,988,835 Stock Option Plan Activity Summary A summary of activity under our stock option plan is as follows: Shares Available For Grant Shares Issuable Under Options Weighted Average Exercise Price Weighted Average Remaining ContractualTerm (In Years) Aggregate Intrinsic Value Balance, December 31, 2012 4,000,000 — Granted (1,410,139) 1,410,139 $ 1.31 Exercised (34,225) $ 0.32 Restricted stock grants (10,200 ) — Balance, December 31, 2013 2,579,661 1,375,914 $ 1.33 Granted (1,127,113 ) 1,127,113 $ 16.23 Exercised (56,112 ) $ 2.17 Forfeited - restricted stock and options 118,750 (117,500 ) $ 19.57 Balance, December 31, 2014 1,571,298 2,329,415 $ 7.60 Granted (922,083 ) 922,083 $ 6.54 Exercised (58,126 ) $ 1.81 Expired 5,104 (5,104 ) $ 19.96 Forfeited - stock options 72,083 (72,083 ) $ 12.48 Balance, December 31, 2015 726,402 3,116,185 $ 7.26 8.2 $ 2,908,000 Options vested and expected to vest, December 31, 2015 3,116,185 $ 7.26 8.2 $ 2,908,000 Options exercisable, December 31, 2015 1,603,594 $ 6.48 7.7 $ 2,338,000 The aggregate intrinsic value of options is calculated as the difference between the exercise price of options and the fair value of our common stock for those options that had exercise prices lower than the fair value of our common stock on December 31, 2015 . The aggregate intrinsic value of stock options exercised during the years ended December 31, 2015 , 2014 and 2013 was $266,000 , $774,000 and $108,000 , respectively. We received proceeds of $105,000 , $121,000 and $11,000 from the exercise of common stock options during the years ended December 31, 2015 , 2014 and 2013, respectively. The weighted-average grant date fair value of options granted during the years ended December 31, 2015 , 2014 and 2013 was $5.03 , $12.09 and $1.50 per share, respectively. Restricted Stock We did not grant any restricted common stock in 2015 and 2014. During the year ended December 31, 2013, we granted 10,200 shares of restricted common stock to consultants. The weighted average fair value of the restricted shares was $6.63 . As of December 31, 2015 , there were no unvested shares of restricted common stock. Stock-Based Compensation We recognize stock-based compensation expense for only the portion of awards that are expected to vest. In developing a forfeiture rate estimate, we have considered our historical experience to estimate pre-vesting forfeitures for service-based awards. The impact of a forfeiture rate adjustment will be recognized in full in the period of adjustment, and if the actual forfeiture rate is materially different from our estimate, we may be required to record adjustments to stock-based compensation expense in future periods. We value our common stock by taking into consideration its most recently available valuation of common stock performed by management and the board of directors, as well as additional factors which may have changed from the date of the most recent contemporaneous valuation through the grant date. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. We historically have been a private company that lacks company-specific historical and implied volatility information. Therefore, we estimate the expected stock volatility based on the historical volatility of publicly traded peer companies and expect to continue to do so until such time as we have adequate historical data regarding the volatility of our own traded stock price. The expected term of our common stock options has been determined utilizing the “simplified” method as we have insufficient historical experience for options grants overall, rendering existing historical experience irrelevant to expectations for current grants. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is based on the fact that we have never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. Total stock-based compensation expense, related to all of our share-based payment awards, is comprised of the following: (In thousands) Years Ended December 31, 2015 2014 2013 Research and development $ 1,857 $ 1,453 $ 827 General and administrative 2,300 2,969 95 $ 4,157 $ 4,422 $ 922 Total stock-based compensation expense included stock options and expense from the Purchase Plan for the year ended December 31, 2015 and stock options and restricted stock for the years ended December 31, 2014 and 2013. We recorded accrued expenses of $303,000 at December 31, 2013, for options which were earned but not granted and approved by the board of directors as of that date. There were no such accruals in 2015 and 2014. We had an aggregate of approximately $8,254,000 of unrecognized stock-based compensation expense for options outstanding and the Purchase Plan as of December 31, 2015 , which is expected to be recognized over a weighted average period of 2.5 years . Valuation assumptions The relevant data used to determine the fair value of stock options earned or granted and the Purchase Plan is as follows: Years Ended December 31, 2015 2014 2013 Stock options: Weighted average risk-free interest rate 1.51% 1.70% 1.33% Weighted average expected term (in years) 6.1 6.4 6.6 Weighted average expected volatility 94.8% 91.3% 85.2% Weighted average expected dividend yield — — — Employee stock purchase plan: Weighted average risk-free interest rate 0.08% — — Weighted average expected term (in years) 0.5 0 0 Weighted average expected volatility 80.7% — — Weighted average expected dividend yield — — —

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies License agreement In March 2014, we entered into a license agreement under which we made an up-front payment and were obligated to make annual payments and, subject to certain terms and conditions, milestone payments upon achievement of development milestones and a royalty based on sales of products developed under the agreement. In January 2015, we terminated this agreement. Operating Leases For the period from September 25, 2012 (inception) through March 2014, we leased our office space on a month-to-month basis. In April 2014, we entered into new non-cancelable operating leases for laboratory space and office space through November 2017. In January, August and November 2015, we amended our original operating lease for laboratory space to expand the facility with an additional 2,431 square feet, 131 square feet and 123 square feet, respectively, of manufacturing space through May 2017. In August 2015, we entered into a new non-cancelable operating lease for 3,126 square feet of office space in San Diego, California through September 2019. In February 2016, we further amended our original operating lease for laboratory space to further expand the facility with an additional 3,599 square feet of quality control laboratory space through May 2017. Rent expense for the years ended December 31, 2015 , 2014 and 2013 was $339,000 , $162,000 and $6,000 , respectively. In addition, we have three operating leases for equipment through 2020. As of December 31, 2015, we are obligated to make minimum lease payments under all of our operating leases, including the amendment entered into in February 2016 (see Note 16), as follows (in thousands): Year ending December 31, Lease Payments 2016 $ 548 2017 402 2018 103 2019 79 2020 2 Total $ 1,134 Indemnities and Guarantees We have made certain indemnities and guarantees, under which we may be required to make payments to a guaranteed or indemnified party, in relation to certain transactions. We indemnify our officers and directors to the maximum extent permitted under the laws of the State of Delaware. The duration of these indemnities and guarantees varies and, in certain cases, is indefinite. These indemnities and guarantees do not provide for any limitation of the maximum potential future payments we could be obligated to make. Historically, we have not been obligated to make any payments for these obligations and no liabilities have been recorded for these indemnities and guarantees in the accompanying balance sheets. Legal Matters In the ordinary course of business, we may face various claims brought by third parties and may, from time to time, make claims or take legal actions to assert our rights, including intellectual property disputes, contractual disputes and other commercial disputes. Any of these claims could subject us to litigation. Management believes there are currently no claims that are likely to have a material effect on our financial position and results of operations.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions We entered into a consulting agreement with S.D. Scientific, a company owned 50% by our co-founder and current Chief Operating Officer. Consulting fees earned by S.D. Scientific during the year ended December 31, 2013 were $54,000 . There were no consulting fees earned by S.D. Scientific in 2015 and 2014. Our co-founder and Chief Executive Officer purchased 31,546 shares of Series A-1 Preferred Stock for $100,000 during the year ended December 31, 2013. In connection with our Series A-1 and Series A-1A Preferred Stock financings in 2013, an entity affiliated with one of our board members purchased 31,546 shares and 15,773 shares of Series A-1 and Series A-1A Preferred Stock, respectively, for $100,000 and $50,000 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes There is no provision for income taxes because we have historically incurred operating losses and we maintain a full valuation allowance against our net deferred tax assets. Differences between the provision (benefit) for income taxes and income taxes at the statutory federal income tax rate are as follows: (In thousands, except percentages) For the years ended December 31, 2015 2014 2013 Income tax expense (benefit) at statutory federal rate $ (9,226 ) 34.0 % $ (9,227 ) 34.0 % $ (1,432 ) 34.0 % State income tax, net of federal benefit (1,678 ) 6.2 (1,663 ) 6.1 (245 ) 5.8 Permanent items 58 (0.2 ) 14 (0.1 ) 2 — Research credits (1,379 ) 5.1 (807 ) 3 (188 ) 4.5 Stock compensation — — — — 6 (0.1 ) ASC 740-10 552 (2.0 ) 323 (1.2 ) 75 (1.8 ) Change in valuation allowance 11,924 (43.9 ) 11,388 (41.9 ) 1,782 (42.4 ) Other individually immaterial items (251 ) 0.8 (28 ) 0.1 — — Provision (benefit) for income taxes $ — — % $ — — % $ — — % Deferred tax assets are recognized for temporary differences that will result in deductible amounts in future periods. The components of the deferred tax assets are as follows at December 31, 2015 and 2014: December 31, (In thousands) 2015 2014 Deferred tax assets: Net operating loss carryforwards $ 19,173 $ 10,047 Research & development credits 1,591 597 Accrued expenses 766 463 Amortization and depreciation (38 ) 4 Other 2 1 Stock-based compensation 3,643 2,101 25,137 13,213 Valuation Allowance (25,137 ) (13,213 ) Net current deferred tax assets $ — $ — At December 31, 2015, we had net deferred tax assets of $25,137,000 . Due to uncertainties surrounding our ability to generate future taxable income to realize these assets, a full valuation allowance has been established to offset the net deferred tax asset. Additionally, the future utilization of our net operating loss and research and development tax credits carryforwards is subject to annual limitation under Sections 382 and 383 of the Internal Revenue Code of 1986, and similar state tax provisions due to ownership change limitations that have occurred previously or that could occur in the future. These ownership changes limit the amount of the net operating loss and research and development tax credit carryforward and other deferred tax assets that can be utilized to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Sections 382 and 383, results from transactions increasing ownership of certain stockholders or public groups in the stock of the corporation by more than 50 percent points over a three-year period. We believe we incurred an ownership change during April 2014, however, we have not completed an analysis yet to determine the impact of our ability to use net operating losses and research and development credits as of December 31, 2015. At December 31, 2015, we had federal and California net operating loss carryovers of $48,289,000 and $48,158,000 , respectively. The federal and California net loss carryforwards will begin to expire in 2032. At December 31, 2015, we had federal and state research tax credit carryovers of approximately $1,614,000 and $1,472,000 , respectively. The federal research and development tax credit carryforwards will begin to expire in 2033. The California research and development credit carryforwards are available indefinitely. The impact of an uncertain income tax position on the income tax return must be recognized at the largest amount that is more likely than not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. There were no unrecognized tax benefits recorded by us as of the date of adoption. As a result of the implementation, we did not recognize an increase in the liability for unrecognized tax benefits. A rollforward of changes in our unrecognized tax benefits is shown below. (In thousands) December 31, 2015 2014 Balance at beginning of year $ 473 $ 91 Additions based on tax positions related to the current year 650 382 Additions for tax positions of prior years 111 — Balance at end of year $ 1,234 $ 473 The amount of unrecognized tax benefits that would impact the effective tax rate if recognized and realized is $1,034,000 . Our practice is to recognize interest and/or penalties related to income tax matters as income tax expense. We had no accrual for interest or penalties on our accompanying balance sheets at December 31, 2015 and 2014, and have not recognized interest and/or penalties in our statements of operations and comprehensive loss for the years ended December 31, 2015, 2014 and 2013. We do not anticipate a significant change to our unrecognized tax benefits during the next twelve months . We file tax returns as prescribed by tax laws of the jurisdictions in which we operate. In the normal course of business, we are subject to examination by federal and state jurisdictions, where applicable. There are currently no pending tax examinations. Our federal and state tax returns are still open under statute from 2012 to present.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic and diluted net loss per share was calculated as follows for the years ended December 31, 2015 , 2014 and 2013: (In thousands, except per share amounts) Years Ended December 31, 2015 2014 2013 Basic and diluted net loss per share attributable to common stockholders: Numerator: Net loss attributable to common stockholders $ (27,130 ) $ (27,139 ) $ (4,213 ) Denominator: Weighted-average number of common shares outstanding, basic and diluted 19,773 18,782 3,732 Net loss per common share attributable to common stockholders, basic and diluted $ (1.37 ) $ (1.44 ) $ (1.13 ) There was no difference between our net loss and the net loss attributable to common stockholders for all periods presented. Stock options to purchase 3,116,185 shares, 2,329,415 shares and 1,375,914 shares of common stock as of December 31, 2015 , 2014 and 2013, respectively, were excluded from the computation of diluted net loss per share attributable to common stockholders because their effect was anti-dilutive.

Employee Savings Plan

Employee Savings Plan	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Savings Plan	Employee Savings Plan We have established an employee savings plan pursuant to Section 401(k) of the Internal Revenue Code, effective May 1, 2014. The plan allows participating employees to deposit into tax deferred investment accounts up to 90% of their salary, subject to annual limits. We make contributions to the plan in an amount equal to 50% on the first 6% for a maximum of 3% of the participant’s compensation which is deferred. We contributed approximately $164,000 and $84,000 to the plan during the years ended December 31, 2015 and 2014, respectively.

Selected Quarterly Financial In

Selected Quarterly Financial Information (unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Information (unaudited)	Selected Quarterly Financial Information (unaudited) The following table presents selected unaudited quarterly financial data for each of the quarters in the years ended December 31, 2015 and 2014. (In thousands, except per share amounts) 2015 2014 Quarter ended Dec. 31 Sep. 30 Jun. 30 Mar. 31 Dec. 31 Sep. 30 Jun. 30 Mar. 31 Operating costs and expenses Research and development $ 4,579 $ 5,033 $ 4,991 $ 4,809 $ 4,802 $ 3,755 $ 5,639 $ 4,498 General and administrative 1,881 2,095 1,921 1,953 2,014 2,342 2,504 1,679 Total operating cost and expenses 6,460 7,128 6,912 6,762 6,816 6,097 8,143 6,177 Loss from operations (6,460 ) (7,128 ) (6,912 ) (6,762 ) (6,816 ) (6,097 ) (8,143 ) (6,177 ) Interest and other income, net 40 33 29 30 27 25 33 9 Net loss $ (6,420 ) $ (7,095 ) $ (6,883 ) $ (6,732 ) $ (6,789 ) $ (6,072 ) $ (8,110 ) $ (6,168 ) Net loss per share, basic and diluted (1) $ (0.32 ) $ (0.36 ) $ (0.35 ) $ (0.34 ) $ (0.34 ) $ (0.31 ) $ (0.42 ) $ (0.38 ) Weighted average shares used in computing net loss per share, basic and diluted 19,816 19,792 19,756 19,726 19,719 19,713 19,426 16,222 (1) Net loss per share for each quarter are calculated as a discrete period; the sum of four quarters may not equal the calculated full year amount.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events We have evaluated subsequent events through the filing date of this annual report on Form 10-K, and determined that no subsequent events have occurred that would require recognition in the financial statements or disclosure in the notes thereto other than as listed below. On January 11, 2016, we announced a corporate restructuring whereby 18 employees were laid-off in order to streamline our focus on our development programs and to ensure our remaining funds at December 31, 2015 are sufficient to fund our planned operations through 2018. The total restructuring charge incurred was $655,000 . On February 3, 2016, we further amended our existing operating lease for laboratory space at the Mitten Road facility. The amendment to the original lease provides for an expansion of an additional 3,599 square feet of laboratory space for a total of 8,429 square feet. The term of the lease is February 3, 2016 through May 31, 2017 and total rent payments from this amendment is expected to be $189,000 .

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”).
Use of Estimates	Use of Estimates The preparation of financial statements and related disclosures in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the valuation of common stock and stock-based awards, the realization of deferred tax assets, the recoverability of long-lived assets and the accrual of research and development expenses. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from those estimates.
Cash, Cash Equivalents and Short-term Investments	Cash, Cash Equivalents and Investments We consider all highly liquid investments purchased with an original maturity of three months or less at the date of acquisition to be cash equivalents. Debt securities with original maturities greater than three months and remaining maturities less than one year are classified as short-term investments. We classify all investments as available-for-sale. Available-for-sale securities are carried at estimated fair value, with accumulated unrealized gains and losses reported as a component of accumulated other comprehensive income (loss) in the accompanying balance sheets. Realized gains or losses on the sale of investments are determined on a specific identification method, and such gains and losses are reflected as a component of interest and other income, net in the accompanying statements of operations and comprehensive loss. Marketable securities investments are evaluated periodically for impairment. We take into account general market conditions, changes in the economic environment as well as specific investment attributes, such as credit downgrade or illiquidity for each investment, the expected cash flows from the securities, our intent to sell the securities and whether or not we will be required to sell the securities before the recovery of their amortized cost, to estimate the fair value of our investments and to determine whether impairment is other than temporary. If it is determined that a decline in fair value of any investment is other than temporary, then the unrealized loss related to credit risk would be included in interest and other income, net.
Concentration of Credit Risk and of Significant Suppliers	Concentration of Credit Risk and of Significant Suppliers Our financial instrument that potentially subjects us to concentrations of credit risk is cash and cash equivalents. From time to time, we maintain cash balances in excess of amounts insured by the Federal Deposit Insurance Corporation (“FDIC”). Primarily all of our cash and cash equivalents at December 31, 2015 were in excess of amounts insured by the FDIC. We do not believe that we are subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. We are dependent on third-party manufacturers to supply products for research and development activities in our programs. In particular, we rely on a small number of manufacturers to supply us with our requirements for the active pharmaceutical ingredients, or API, and formulated drugs related to some of these programs. These programs would be adversely affected by a significant interruption in the supply of API.
Fair Value Measurements	Fair Value Measurements We use the provisions of Accounting Standards Codification ("ASC") 820, “Fair Value Measurements and Disclosure" , to determine the fair values of our financial and nonfinancial assets and liabilities where applicable. ASC 820 defines fair value, establishes a framework for measuring fair value in U.S. GAAP and expands disclosure about fair value measurements. The objective of fair value measurement is to determine the price that would be received to sell the asset or paid to transfer the liability (an exit price) in an orderly transaction between market participants at the measurement date. ASC 820 emphasizes that fair value is a market-based measurement, not an entity-specific measurement, and that market participant assumptions include assumptions about risk and effect of a restriction on the sale or use of an asset. To increase consistency and comparability in fair value measurement and related disclosures, ASC 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels: (1) Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date; (2) Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly through corroboration with observable market data; and (3) Level 3 inputs are unobservable inputs for the asset or liability that reflect the reporting entity’s own assumptions about risk and the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. Government agency securities are recorded at their estimated fair value. Since these government securities generally have market prices from multiple sources and it can be difficult to select the best individual price directly from the quoted prices in the active markets, we use Level 2 inputs for the valuation of these securities. Using the Level 2 inputs, a “consensus price” or a weighted average price for each of these securities can be derived from a distribution-curve-based algorithm which includes market prices obtained from a variety of industrial standard data providers (e.g. Bloomberg), security master files from large financial institutions, and other third-party sources. The carrying amount of financial instruments, including cash, accounts payable and accrued liabilities approximate fair value due to the short maturities of these financial instruments. Financial assets, which consist of money market funds and available-for-sale securities, are measured at fair value on a recurring basis (see Note 3).
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation and amortization. We calculate depreciation using the straight-line method over the estimated useful lives of the assets, which range from two to five years. Expenditures for repairs and maintenance of assets are charged to expense as incurred. We amortize leasehold improvements using the straight-line method over the estimated useful lives of the respective assets or the lease term, whichever is shorter. Upon retirement or sale, the cost and related accumulated depreciation and amortization of assets disposed of are removed from the accounts and any resulting gain or loss is included in other income/expense.
Licenses	Licenses The costs incurred for the rights to use licensed technologies in the research and development process, including licensing fees and milestone payments, are charged to research and development expense as incurred in situations where we have not identified an alternative future use for the acquired rights, and are capitalized in situations where we have identified an alternative future use. No costs associated with the use of licensed technologies have been capitalized to date.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets We review long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that we consider in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends, and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long-lived asset for recoverability, we compare forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long-lived asset to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset over its fair value, determined based on discounted cash flows. To date, we have not recorded any impairment losses on long-lived assets.
Revenue Recognition	Revenue Recognition We are in the research and development stage and have not generated any revenues since inception.
Research and Development Costs	Research and Development Costs All costs of research and development are expensed in the period incurred. Research and development costs primarily consist of salaries and related expenses for personnel, stock-based compensation expense, fees paid to consultants, outside service providers, professional services, travel costs and materials used in clinical trials and research and development.
Patent Costs	Patent Costs All patent-related costs incurred in connection with filing patent applications are recorded in research and development expenses when incurred, as recoverability of such expenditures is uncertain.
Stock-Based Compensation	Stock-Based Compensation Our stock-based compensation plan (see Note 9) provides for the grant of stock options, restricted common stock and stock appreciation rights. The estimated fair values of stock option grants are determined as of the date of grant using the Black-Scholes option pricing model. This method incorporates the fair value of our common stock at the date of each grant and various assumptions such as the risk-free interest rate, expected volatility based on the historic volatility of publicly-traded peer companies, expected dividend yield, and expected term of the options. The estimated fair values of restricted stock awards are determined based on the fair value of our common stock on the date of grant. The estimated fair values of stock-based awards, including the effect of estimated forfeitures, are expensed over the requisite service period, which is generally the awards’ vesting period. We classify stock-based compensation expense in the statement of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified. Our accounting policy for equity instruments issued to consultants and vendors in exchange for goods and services follows Financial Accounting Standards Board ("FASB") guidance. All transactions in which goods or services are the consideration received for the issuance of equity instruments are accounted for based on the fair value of the consideration received or the fair value of the equity instrument issued, whichever is more reliably measurable. The measurement date of the fair value of the equity instrument issued is the earlier of the date on which the counterparty’s performance is complete or the date at which a commitment for performance is reached. For transactions in which the fair value of the equity instrument issued to non-employees is the more reliable measurement and a measurement date has not been reached, the fair value is re-measured at each reporting date using the Black-Scholes option pricing model. Compensation expense for these share-based awards is recognized over the term of the consulting agreement or until the award is approved and settled.
Income Taxes	Income Taxes We account for income taxes using 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 recognized in the financial statements or in our tax returns. Deferred taxes are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. We assess the likelihood that our deferred tax assets will be recovered from future taxable income and, to the extent we believe, based upon the weight of available evidence, that it is more likely than not that all or a portion of deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. We account for uncertainty in income taxes recognized in the financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.
Comprehensive Loss	Comprehensive Loss Our comprehensive loss includes the change in unrealized gains or losses on available-for-sale securities. The cumulative amount of gains or losses is reflected as a separate component of stockholders' equity in the accompanying balance sheets as accumulated other comprehensive loss.
Segment Data	Segment Data We manage our operations as a single segment for the purposes of assessing performance and making operating decisions. We are a veterinary biotechnology company focusing on developing therapies for pets. Our chief operating decision maker is our Chief Executive Officer. All assets are held in the United States.
Basic and Diluted Net Loss Per Common Share	Basic and Diluted Net Loss Per Common Share Basic net loss per common share is computed by dividing net loss attributable to common stockholders for the period by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders for the period by the weighted average number of common shares, including potential dilutive shares of common stock assuming the dilutive effect of potentially dilutive securities. For periods in which we have reported a net loss, diluted net loss per common share is the same as basic net loss per common share, since the impact of the potentially dilutive securities would be anti-dilutive to the calculation of net loss per common share (see Note 13).
Recently Issued Accounting Pronouncements	Recently Issued 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" , which provides guidance regarding management’s responsibility to assess whether substantial doubt exists regarding the ability to continue as a going concern and to provide related footnote disclosures. In connection with preparing financial statements for each annual and interim reporting period, management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the company’s ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). Our adoption of this standard did not have any material impact on our financial statements. In November 2015, the FASB issued ASU No. 2015-17, "Balance Sheet Classification of Deferred Taxes" , requiring all deferred tax assets and liabilities, and any related valuation allowance, to be classified as non-current on the balance sheet. The classification change for all deferred taxes as non-current simplifies entities’ processes as it eliminates the need to separately identify the net current and net non-current deferred tax asset or liability in each jurisdiction and allocate valuation allowances. The update is effective for public business entities issuing financial statements for the annual periods beginning after December 15, 2016, and interim periods within those annual periods. We are currently evaluating the new guidance and have not determined the impact this standard may have on our financial statements. In January 2016, the FASB issued ASU No. 2016-01, "Financial Instruments—Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities" , which amends the guidance in U.S. GAAP on the classification and measurement of financial instruments and also amends certain disclosure requirements associated with the fair value of financial instruments. The new guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We are currently evaluating the new guidance and have not determined the impact this standard may have on our financial statements. In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" , requiring organizations that lease assets—referred to as “lessees”—to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those leases. Under the new guidance, a lessee will be required to recognize assets and liabilities for leases with lease terms of more than 12 months. The ASU on leases will take effect for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. We are currently evaluating the new guidance and have not determined the impact this standard may have on our financial statements. We do not believe there are any other recently issued standards not yet effective that will have a material impact on our financial statements when the standards become effective.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of financial assets measured at fair value on a recurring basis	The following table presents information about our financial assets that are measured at fair value on a recurring basis as of December 31, 2015 and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value: (In thousands) Fair Value Measurements as of December 31, 2015 Description Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Cash equivalents: Money market funds $ 8,169 $ 8,169 $ — $ — U.S. government agency notes 4,385 — 4,385 — Short-term investments: U.S. treasury bills 41,282 — 41,282 — U.S. government agency notes 11,769 — 11,769 — Long-term investments: U.S. treasury bills 4,590 — 4,590 — $ 70,195 $ 8,169 $ 62,026 $ — The following table presents information about our financial assets that are measured at fair value on a recurring basis as of December 31, 2014 and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value: (In thousands) Fair Value Measurements as of December 31, 2014 Description Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Cash equivalents: Money market funds $ 834 $ 834 $ — $ — Short-term investments: U.S. treasury bills 5,998 — 5,998 — U.S. government agency notes 82,060 — 82,060 — $ 88,892 $ 834 $ 88,058 $ —

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Schedule of fair value of available-for-sale short term investments	The following tables summarize our investments in available-for-sale securities by significant investment category reported as short-term or long-term investments as of December 31, 2015 and 2014 (in thousands): December 31, 2015 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term investments: U.S. treasury bills $ 41,293 $ 14 $ (25 ) $ 41,282 U.S. government agency notes 11,776 — (7 ) 11,769 U.S. treasury bonds and notes 25 9 (34 ) — 53,094 23 (66 ) 53,051 Long-term investments: U.S. treasury bills 4,597 — (7 ) 4,590 Total available-for-sale investments $ 57,691 $ 23 $ (73 ) $ 57,641 December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term investments: U.S. treasury bills $ 5,994 $ 4 $ — $ 5,998 U.S. treasury bonds and notes 82,091 — (31 ) 82,060 Total available-for-sale investments $ 88,085 $ 4 $ (31 ) $ 88,058 The following table summarizes the contractual maturities of our available-for-sale securities at December 31, 2015 (in thousands): Amortized Cost Fair Value Mature in less than one year $ 53,094 $ 53,051 Mature in one year or more $ 4,597 $ 4,590

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment, Net [Abstract]
Schedule of property and equipment	Property and equipment consisted of the following: As of December 31, (in thousands) 2015 2014 Computer and lab equipment $ 437 $ 359 Furniture & fixtures 38 24 Leasehold improvements 78 69 Construction-in-process 895 — Total 1,448 452 Less accumulated depreciation and amortization (204 ) (58) Property and equipment, net $ 1,244 $ 394

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Payables and Accruals [Abstract]
Schedule of accrued liabilities	Accrued liabilities consisted of the following as of December 31, 2015 and 2014 : (In thousands) December 31, 2015 December 31, 2014 Accrued consulting $ 83 $ — Accrued research and development costs 345 715 Accrued other 128 247 Deferred rent 53 57 609 1,019 Less current portion (569 ) (975 ) Long-term liability (deferred rent) $ 40 $ 44

Stock-Based Awards (Tables)

Stock-Based Awards (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of shares of common stock reserved for future issuance	At December 31, 2015, shares of common stock reserved for future issuance inclusive of outstanding option shares are as follows: 2012 Equity Incentive Plan 3,842,587 2014 Employee Stock Purchase Plan 146,248 3,988,835
Summary of activity under stock option plans	A summary of activity under our stock option plan is as follows: Shares Available For Grant Shares Issuable Under Options Weighted Average Exercise Price Weighted Average Remaining ContractualTerm (In Years) Aggregate Intrinsic Value Balance, December 31, 2012 4,000,000 — Granted (1,410,139) 1,410,139 $ 1.31 Exercised (34,225) $ 0.32 Restricted stock grants (10,200 ) — Balance, December 31, 2013 2,579,661 1,375,914 $ 1.33 Granted (1,127,113 ) 1,127,113 $ 16.23 Exercised (56,112 ) $ 2.17 Forfeited - restricted stock and options 118,750 (117,500 ) $ 19.57 Balance, December 31, 2014 1,571,298 2,329,415 $ 7.60 Granted (922,083 ) 922,083 $ 6.54 Exercised (58,126 ) $ 1.81 Expired 5,104 (5,104 ) $ 19.96 Forfeited - stock options 72,083 (72,083 ) $ 12.48 Balance, December 31, 2015 726,402 3,116,185 $ 7.26 8.2 $ 2,908,000 Options vested and expected to vest, December 31, 2015 3,116,185 $ 7.26 8.2 $ 2,908,000 Options exercisable, December 31, 2015 1,603,594 $ 6.48 7.7 $ 2,338,000
Schedule of stock-based compensation expense	Total stock-based compensation expense, related to all of our share-based payment awards, is comprised of the following: (In thousands) Years Ended December 31, 2015 2014 2013 Research and development $ 1,857 $ 1,453 $ 827 General and administrative 2,300 2,969 95 $ 4,157 $ 4,422 $ 922
Schedule of valuation assumptions	The relevant data used to determine the fair value of stock options earned or granted and the Purchase Plan is as follows: Years Ended December 31, 2015 2014 2013 Stock options: Weighted average risk-free interest rate 1.51% 1.70% 1.33% Weighted average expected term (in years) 6.1 6.4 6.6 Weighted average expected volatility 94.8% 91.3% 85.2% Weighted average expected dividend yield — — — Employee stock purchase plan: Weighted average risk-free interest rate 0.08% — — Weighted average expected term (in years) 0.5 0 0 Weighted average expected volatility 80.7% — — Weighted average expected dividend yield — — —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	As of December 31, 2015, we are obligated to make minimum lease payments under all of our operating leases, including the amendment entered into in February 2016 (see Note 16), as follows (in thousands): Year ending December 31, Lease Payments 2016 $ 548 2017 402 2018 103 2019 79 2020 2 Total $ 1,134

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Differences between provision (benefit) for income taxes and income taxes at the statutory federal income tax rate	Differences between the provision (benefit) for income taxes and income taxes at the statutory federal income tax rate are as follows: (In thousands, except percentages) For the years ended December 31, 2015 2014 2013 Income tax expense (benefit) at statutory federal rate $ (9,226 ) 34.0 % $ (9,227 ) 34.0 % $ (1,432 ) 34.0 % State income tax, net of federal benefit (1,678 ) 6.2 (1,663 ) 6.1 (245 ) 5.8 Permanent items 58 (0.2 ) 14 (0.1 ) 2 — Research credits (1,379 ) 5.1 (807 ) 3 (188 ) 4.5 Stock compensation — — — — 6 (0.1 ) ASC 740-10 552 (2.0 ) 323 (1.2 ) 75 (1.8 ) Change in valuation allowance 11,924 (43.9 ) 11,388 (41.9 ) 1,782 (42.4 ) Other individually immaterial items (251 ) 0.8 (28 ) 0.1 — — Provision (benefit) for income taxes $ — — % $ — — % $ — — %
Components of deferred tax assets	The components of the deferred tax assets are as follows at December 31, 2015 and 2014: December 31, (In thousands) 2015 2014 Deferred tax assets: Net operating loss carryforwards $ 19,173 $ 10,047 Research & development credits 1,591 597 Accrued expenses 766 463 Amortization and depreciation (38 ) 4 Other 2 1 Stock-based compensation 3,643 2,101 25,137 13,213 Valuation Allowance (25,137 ) (13,213 ) Net current deferred tax assets $ — $ —
Rollforward of changes in unrecognized tax benefits	A rollforward of changes in our unrecognized tax benefits is shown below. (In thousands) December 31, 2015 2014 Balance at beginning of year $ 473 $ 91 Additions based on tax positions related to the current year 650 382 Additions for tax positions of prior years 111 — Balance at end of year $ 1,234 $ 473

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Calculation of basic and diluted net loss per share	Basic and diluted net loss per share was calculated as follows for the years ended December 31, 2015 , 2014 and 2013: (In thousands, except per share amounts) Years Ended December 31, 2015 2014 2013 Basic and diluted net loss per share attributable to common stockholders: Numerator: Net loss attributable to common stockholders $ (27,130 ) $ (27,139 ) $ (4,213 ) Denominator: Weighted-average number of common shares outstanding, basic and diluted 19,773 18,782 3,732 Net loss per common share attributable to common stockholders, basic and diluted $ (1.37 ) $ (1.44 ) $ (1.13 )

Selected Quarterly Financial 33

Selected Quarterly Financial Information (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Unaudited quarterly financial data	The following table presents selected unaudited quarterly financial data for each of the quarters in the years ended December 31, 2015 and 2014. (In thousands, except per share amounts) 2015 2014 Quarter ended Dec. 31 Sep. 30 Jun. 30 Mar. 31 Dec. 31 Sep. 30 Jun. 30 Mar. 31 Operating costs and expenses Research and development $ 4,579 $ 5,033 $ 4,991 $ 4,809 $ 4,802 $ 3,755 $ 5,639 $ 4,498 General and administrative 1,881 2,095 1,921 1,953 2,014 2,342 2,504 1,679 Total operating cost and expenses 6,460 7,128 6,912 6,762 6,816 6,097 8,143 6,177 Loss from operations (6,460 ) (7,128 ) (6,912 ) (6,762 ) (6,816 ) (6,097 ) (8,143 ) (6,177 ) Interest and other income, net 40 33 29 30 27 25 33 9 Net loss $ (6,420 ) $ (7,095 ) $ (6,883 ) $ (6,732 ) $ (6,789 ) $ (6,072 ) $ (8,110 ) $ (6,168 ) Net loss per share, basic and diluted (1) $ (0.32 ) $ (0.36 ) $ (0.35 ) $ (0.34 ) $ (0.34 ) $ (0.31 ) $ (0.42 ) $ (0.38 ) Weighted average shares used in computing net loss per share, basic and diluted 19,816 19,792 19,756 19,726 19,719 19,713 19,426 16,222 (1) Net loss per share for each quarter are calculated as a discrete period; the sum of four quarters may not equal the calculated full year amount.

Organization and Description 34

Organization and Description of Business (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Accumulated deficit	$ 58,602	$ 31,472
Other Long-term Investments [Member]
Debt Instrument [Line Items]
Cash, cash equivalents and short-term investments	$ 77,633

Summary of Significant Accoun35

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2015
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	2 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	5 years

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements
Available-for-sale Securities	$ 57,641	$ 88,058
Short-term investments	53,051	88,058
U.S. treasury bills
Fair Value Measurements
Available-for-sale Securities		5,998
Financial assets measured at fair value on a recurring basis
Fair Value Measurements
Cash equivalents		834
Total assets	70,195	88,892
Financial assets measured at fair value on a recurring basis | Money Market Funds [Member]
Fair Value Measurements
Cash equivalents	8,169
Financial assets measured at fair value on a recurring basis | U.S. treasury bills
Fair Value Measurements
Available-for-sale Securities		5,998
Short-term investments	41,282
Financial assets measured at fair value on a recurring basis | U.S. government agency notes
Fair Value Measurements
Cash equivalents	4,385
Available-for-sale Securities		82,060
Short-term investments	11,769
Financial assets measured at fair value on a recurring basis | US Treasury Bill Securities [Member]
Fair Value Measurements
Short-term investments	4,590
Financial assets measured at fair value on a recurring basis | Quoted Prices in Active Markets (Level 1)
Fair Value Measurements
Cash equivalents		834
Total assets	8,169	834
Financial assets measured at fair value on a recurring basis | Quoted Prices in Active Markets (Level 1) | Money Market Funds [Member]
Fair Value Measurements
Cash equivalents	8,169
Financial assets measured at fair value on a recurring basis | Quoted Prices in Active Markets (Level 1) | U.S. treasury bills
Fair Value Measurements
Available-for-sale Securities		0
Short-term investments	0
Financial assets measured at fair value on a recurring basis | Quoted Prices in Active Markets (Level 1) | U.S. government agency notes
Fair Value Measurements
Cash equivalents	0
Available-for-sale Securities		0
Short-term investments	0
Financial assets measured at fair value on a recurring basis | Quoted Prices in Active Markets (Level 1) | US Treasury Bill Securities [Member]
Fair Value Measurements
Short-term investments	0
Financial assets measured at fair value on a recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value Measurements
Cash equivalents		0
Total assets	62,026	88,058
Financial assets measured at fair value on a recurring basis | Significant Other Observable Inputs (Level 2) | Money Market Funds [Member]
Fair Value Measurements
Cash equivalents	0
Financial assets measured at fair value on a recurring basis | Significant Other Observable Inputs (Level 2) | U.S. treasury bills
Fair Value Measurements
Available-for-sale Securities		5,998
Short-term investments	41,282
Financial assets measured at fair value on a recurring basis | Significant Other Observable Inputs (Level 2) | U.S. government agency notes
Fair Value Measurements
Cash equivalents	4,385
Available-for-sale Securities		82,060
Short-term investments	11,769
Financial assets measured at fair value on a recurring basis | Significant Other Observable Inputs (Level 2) | US Treasury Bill Securities [Member]
Fair Value Measurements
Short-term investments	4,590
Financial assets measured at fair value on a recurring basis | Unobservable Inputs (Level 3)
Fair Value Measurements
Cash equivalents		0
Total assets	0	0
Financial assets measured at fair value on a recurring basis | Unobservable Inputs (Level 3) | Money Market Funds [Member]
Fair Value Measurements
Cash equivalents	0
Financial assets measured at fair value on a recurring basis | Unobservable Inputs (Level 3) | U.S. treasury bills
Fair Value Measurements
Available-for-sale Securities		0
Short-term investments	0
Financial assets measured at fair value on a recurring basis | Unobservable Inputs (Level 3) | U.S. government agency notes
Fair Value Measurements
Cash equivalents	0
Available-for-sale Securities		$ 0
Short-term investments	0
Financial assets measured at fair value on a recurring basis | Unobservable Inputs (Level 3) | US Treasury Bill Securities [Member]
Fair Value Measurements
Short-term investments	$ 0

Investments (Details)

Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 57,691	$ 88,085
Gross Unrealized Gains	23	4
Gross Unrealized Losses	(73)	(31)
Fair value of available-for-sale securities	57,641	88,058
Mature in less than one year, Amortized cost	53,094
Mature in less than one year, Fair value	53,051
Mature in one year or more, Amortized cost	4,597
Mature in one year or more, Fair value	4,590
U.S. treasury bills
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		5,994
Gross Unrealized Gains		4
Gross Unrealized Losses		0
Fair value of available-for-sale securities		5,998
US Treasury Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		82,091
Gross Unrealized Gains		0
Gross Unrealized Losses		(31)
Fair value of available-for-sale securities		$ 82,060
Available-for-Sale Securities, Maturity Period One [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	53,094
Gross Unrealized Gains	23
Gross Unrealized Losses	(66)
Fair value of available-for-sale securities	53,051
Available-for-Sale Securities, Maturity Period One [Member] | U.S. treasury bills
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	41,293
Gross Unrealized Gains	14
Gross Unrealized Losses	(25)
Fair value of available-for-sale securities	41,282
Available-for-Sale Securities, Maturity Period One [Member] | U.S. government agency notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,776
Gross Unrealized Gains	0
Gross Unrealized Losses	(7)
Fair value of available-for-sale securities	11,769
Available-for-Sale Securities, Maturity Period One [Member] | US Treasury Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	25
Gross Unrealized Gains	9
Gross Unrealized Losses	(34)
Fair value of available-for-sale securities	0
Available-for-Sale Securities, Maturity Period Two [Member] | U.S. treasury bills
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,597
Gross Unrealized Gains	0
Gross Unrealized Losses	(7)
Fair value of available-for-sale securities	$ 4,590

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,448	$ 452
Less accumulated depreciation and amortization	(204)	(58)
Property and equipment, net	1,244	394
Depreciation and amortization expense	146	58	$ 3
Computer and lab equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	437	359
Furniture & fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	38	24
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	78	69
Construction-in-process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 895	$ 0

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued consulting	$ 83	$ 0
Accrued research and development costs	345	715
Accrued other	128	247
Deferred rent	53	57
Accrued liabilities	609	1,019
Less current portion	(569)	(975)
Long-term liability (deferred rent)	$ 40	$ 44

Convertible Preferred Stock (De

Convertible Preferred Stock (Details) $ / shares in Units, $ in Thousands	Dec. 31, 2013$ / sharesshares	Apr. 30, 2014USD ($)shares	Dec. 31, 2013USD ($)$ / sharesshares	Nov. 30, 2013shares	Aug. 31, 2013USD ($)$ / sharesshares	Jun. 30, 2013USD ($)$ / sharesshares	Sep. 30, 2013USD ($)shares	Dec. 31, 2015USD ($)$ / shares	Dec. 31, 2014USD ($)shares	Dec. 31, 2013USD ($)$ / sharesshares	Dec. 16, 2013$ / sharesshares
Class of Stock [Line Items]
Preferred stock, shares authorized	10,000,000		10,000,000							10,000,000
Preferred stock, par value | $ / shares	$ 0.0001		$ 0.0001							$ 0.0001
Issuance of common stock and stock options for accrued consulting expenses | $										$ 12
Series A-1 Preferred Stock
Class of Stock [Line Items]
Proceeds from issuance of convertible preferred stock | $								$ 0	$ 0	5,865
Series A-1 Preferred Stock | Co-Founder and CEO
Class of Stock [Line Items]
Number of shares issued during period									31,546
Series A-1A Preferred Stock
Class of Stock [Line Items]
Proceeds from issuance of convertible preferred stock | $								$ 0	$ 0	$ 5,232
Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized											15,000,000
Preferred stock, par value | $ / shares											$ 0.0001
Preferred Stock | Series AA Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued											1,015,000
Conversion of Series AA, A-1 and A-1A preferred stock to common stock in connection with initial public offering, shares										(1,015,000)
Number of shares issued during period				15,000						15,000
Payments of offering costs | $										$ 13
Benchmark of ownership that allows a unitholder to purchase new shares under the IPO	10,000
Liquidation preference per share | $ / shares								$ 1
Conversion price per share | $ / shares								1
Conversion ratio	1
Preferred Stock | Series A-1 Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized						2,000,000
Preferred stock, shares issued											1,860,204
Conversion of Series AA, A-1 and A-1A preferred stock to common stock in connection with initial public offering, shares										(1,860,000)
Number of shares issued during period					5,000	1,850,204				1,850,000
Share price | $ / shares						$ 3.17
Proceeds from issuance of convertible preferred stock | $						$ 5,865
Payments of offering costs | $						$ 22			22
Issuance of stock for services, in shares						5,000				10,000
Benchmark of ownership that allows a unitholder to purchase new shares under the IPO	10,000
Issuance of common stock and stock options for accrued consulting expenses | $					$ 16	$ 16				$ 32
Percentage of purchase price						10.00%
Liquidation preference per share | $ / shares								3.17
Conversion price per share | $ / shares								$ 3.17
Conversion ratio								1
Preferred Stock | Series A-1A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized					2,000,000
Preferred stock, shares issued											1,675,002
Conversion of Series AA, A-1 and A-1A preferred stock to common stock in connection with initial public offering, shares										(1,675,000)
Number of shares issued during period					24,606		1,650,396			1,650,000
Share price | $ / shares					$ 3.17
Proceeds from issuance of convertible preferred stock | $							$ 5,232
Payments of offering costs | $							$ 88		$ 88
Issuance of stock for services, in shares										25,000
Benchmark of ownership that allows a unitholder to purchase new shares under the IPO	10,000
Issuance of common stock and stock options for accrued consulting expenses | $					$ 78					$ 78
Percentage of purchase price					10.00%
Liquidation preference per share | $ / shares								$ 3.17
Conversion price per share | $ / shares								$ 3.17
Conversion ratio								1
Common Stock
Class of Stock [Line Items]
Conversion of Series AA, A-1 and A-1A preferred stock to common stock in connection with initial public offering, shares										4,550,000
Number of shares issued during period		3,450,000	8,625,000						3,450,000	8,625,000
Payments of offering costs | $		$ 4,035	$ 5,504					$ 4,035	$ 5,504
Issuance of stock for services, in shares										5,000
Common Stock | Conversion of Preferred Stock
Class of Stock [Line Items]
Conversion of Series AA, A-1 and A-1A preferred stock to common stock in connection with initial public offering, shares	4,550,195
Conversion of shares, fractional shares adjustment	11

Common Stock (Details)

Common Stock (Details) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Apr. 30, 2014USD ($)$ / sharesshares	Dec. 31, 2013USD ($)$ / sharesshares	Aug. 31, 2013USD ($)$ / sharesshares	Dec. 31, 2015USD ($)vote$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	Dec. 31, 2013USD ($)$ / sharesshares
Class of Stock [Line Items]
Number of common shares authorized | shares				100,000,000	100,000,000
Par value of common shares | $ / shares				$ 0.0001	$ 0.0001
Stock-based compensation expense				$ 4,157	$ 4,422	$ 922
Net proceeds from initial public offering	$ 58,065			0	58,065	0
Net proceeds from initial public offering				$ 0	$ 0	$ 54,871
Exercise of common stock options, in shares | shares				58,126	56,112	34,225
Exercise of stock options and purchase of ESPP shares				$ 105	$ 121	$ 11
Common stock, shares outstanding | shares				19,836,360
Common Stock
Class of Stock [Line Items]
Number of voting rights | vote				1
Restricted stock issued | shares					4,000
Share price | $ / shares	$ 18	$ 7				$ 7
Number of shares issued during period | shares	3,450,000	8,625,000			3,450,000	8,625,000
Net proceeds from initial public offering		$ 54,871
Payments of underwriting commissions and offering expenses	$ 4,035	$ 5,504		$ 4,035	$ 5,504
Exercise of common stock options, in shares | shares				58,000	56,000	34,000
Common stock issued under ESPP, shares | shares				53,752
Proceeds from ESPP				$ 238
Common Stock | Consultants | Restricted Common Stock
Class of Stock [Line Items]
Restricted stock issued | shares			5,200		3,750
Share price | $ / shares			$ 2.27
Stock-based compensation expense			$ 12		$ 61
Common Stock | Employee | Employee Stock Option
Class of Stock [Line Items]
Share price | $ / shares		$ 0.32				$ 0.32
Net proceeds from initial public offering						$ 11
Exercise of common stock options, in shares | shares				58,126	56,112	34,225
Exercise of stock options and purchase of ESPP shares				$ 105	$ 121
Common Stock | Employee | Employee Stock Option | Minimum
Class of Stock [Line Items]
Stock option exercised, price | $ / shares				$ 0.32	$ 0.32
Common Stock | Employee | Employee Stock Option | Maximum
Class of Stock [Line Items]
Stock option exercised, price | $ / shares				$ 3.83	$ 15.41

Stock-Based Awards - Narrative

Stock-Based Awards - Narrative (Details) - USD ($)	Jan. 01, 2015	Nov. 11, 2013	Nov. 10, 2013	Sep. 12, 2013	Aug. 29, 2013	May. 09, 2013	Feb. 04, 2013	Nov. 04, 2012	Dec. 31, 2014	Sep. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance											3,988,835
Number of shares of common stock issued upon exercise of stock options, in shares											922,083	1,127,113	1,410,139
Weighted-average exercise price per share, in dollars per share											$ 6.54	$ 16.23	$ 1.31
Fair value of common stock per share											$ 5.03	$ 12.09	$ 1.50
Number of shares issuable under options, in shares									2,329,415		3,116,185	2,329,415	1,375,914	0
Number of shares available for grant, in shares									1,571,298		726,402	1,571,298	2,579,661	4,000,000
Common stock reserved for future issuance											146,248
Aggregate intrinsic value of stock options exercised											$ 266,000	$ 774,000	$ 108,000
Proceeds from exercise of common stock options											105,000	121,000	11,000
Accrued expenses for options earned but not granted and approved									$ 0		0	$ 0	$ 303,000
Unrecognized stock-based compensation expense											$ 8,254,000
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period of stock option plan											10 years
Percent of fair value per share of common stock											100.00%
Benchmark ownership percentage of all classes of stock											10.00%
Percent of fair value per share of common stock, if person owns 10% of all classes											110.00%
Weighted average period for recognition											2 years 6 months
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted													10,200
Restricted stock awards granted, weighted average fair value													$ 6.63
Minimum | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of options											1 year
Maximum | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of options											4 years
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period of stock option plan								10 years
Shares reserved for future issuance								4,000,000			3,842,587
Number of shares of common stock issued upon exercise of stock options, in shares				29,000	412,580	154,793	576,525			285,092
Weighted-average exercise price per share, in dollars per share		$ 1.37	$ 0.90	$ 0.90	$ 0.90	$ 0.32	$ 0.35
Fair value of common stock per share				2.27	2.27	$ 0.32	$ 0.32
2012 Equity Incentive Plan | Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares of common stock issued upon exercise of stock options, in shares											922,083	1,127,113
2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance											146,248
2014 Employee Stock Purchase Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance									200,000			200,000
Consecutive offering period for purchase plan									6 months
Initial offering period for purchase plan	5 months
Purchase price of common stock, percent of fair market value											85.00%
Maximum number of shares per employee									2,000
Maximum value of shares per employee									$ 25,000
Weighted average grant date fair value											$ 2.08
Accrued compensation											$ 25,000
Previously Reported | 2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of common stock per share				$ 1.37	$ 1.37
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued under ESPP, shares											53,752

Stock-Based Awards - Reserved S

Stock-Based Awards - Reserved Shares (Details) - shares	Dec. 31, 2015	Nov. 04, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for future issuance	3,988,835
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for future issuance	3,842,587	4,000,000
2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for future issuance	146,248

Stock-Based Awards - Stock Opti

Stock-Based Awards - Stock Option Plan Activity Summary (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Shares
Number of shares available for grant, beginning balance, in shares	1,571,298	2,579,661	4,000,000
Number of shares issuable under options, beginning balance, in shares	2,329,415	1,375,914	0
Granted, in shares	(922,083)	(1,127,113)	(1,410,139)
Exercised, in shares	(58,126)	(56,112)	(34,225)
Expired, in shares	(5,104)
Restricted stock grants, in shares			(10,200)
Forfeited restricted stock, in shares	72,083	118,750
Forfeited options, in shares	(72,083)	(117,500)
Number of shares available for grant, ending balance, in shares	726,402	1,571,298	2,579,661
Number of shares issuable under options, ending balance, in shares	3,116,185	2,329,415	1,375,914
Weighted Average Exercise Price
Granted, in dollars per share	$ 6.54	$ 16.23	$ 1.31
Exercised, in dollars per share	1.81	2.17	0.32
Expired, in dollars per share	19.96
Forfeited - restricted stock and options, in dollars per share		19.57
Forfeited - stock options, in dollars per share	12.48
Outstanding, in dollars per share	$ 7.26	$ 7.60	$ 1.33
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted Average Remaining Contractual Term (In Years)	8 years 2 months 12 days
Aggregate Intrinsic Value	$ 2,908
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Options vested and expected to vest, shares issuable under options, in shares	3,116,185
Options vested and expected to vest, weighted average exercise price, in dollars per share	$ 7.26
Options vested and expected to vest, weighted average remaining contractual term (in years)	8 years 2 months 12 days
Options vested and expected to vest, aggregate intrinsic value	$ 2,908
Options exercisable, shares issuable under options, in shares	1,603,594
Options exercisable, weighted average exercise price, in dollars per share	$ 6.48
Options exercisable, weighted average remaining contractual term (in years)	7 years 8 months 12 days
Options exercisable, aggregate intrinsic value	$ 2,338

Stock-Based Awards - Stock-Base

Stock-Based Awards - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,157	$ 4,422	$ 922
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,857	1,453	827
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,300	$ 2,969	$ 95

Stock-Based Awards - Valuation

Stock-Based Awards - Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average risk-free interest rate	1.51%	1.70%	1.33%
Weighted average expected term (in years)	6 years 1 month 6 days	6 years 4 months 24 days	6 years 7 months 6 days
Weighted average expected volatility	94.80%	91.30%	85.20%
Weighted average expected dividend yield	0.00%	0.00%	0.00%
Employee Stock Option | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average risk-free interest rate			0.62%
Employee Stock Option | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average risk-free interest rate			0.72%
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average risk-free interest rate	0.08%	0.00%	0.00%
Weighted average expected term (in years)	6 months	0 years	0 years
Weighted average expected volatility	80.70%	0.00%	0.00%
Weighted average expected dividend yield	0.00%	0.00%	0.00%

Commitments and Contingencies47

Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)equipment_lease	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Nov. 30, 2015ft²	Aug. 31, 2015ft²	Jan. 31, 2015ft²	Jan. 14, 2015ft²
Property Subject to or Available for Operating Lease [Line Items]
Rent expense	$ 339	$ 162	$ 6
Capital leased assets, number of units | equipment_lease	3
Lease Payments
2,016	$ 548
2,017	402
2,018	103
2,019	79
2,020	2
Total	$ 1,134
Property Subject to Operating Lease | Laboratory space
Property Subject to or Available for Operating Lease [Line Items]
Additional area of real estate property | ft²				123	131	2,431	3,599
Area of real estate property | ft²					3,126

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Value of stock issued		$ 58,065	$ 54,872
Co-Founder and CEO | Series A-1 Preferred Stock
Related Party Transaction [Line Items]
Number of shares issued during period		31,546
Value of stock issued		$ 100
Co-Founder and CEO | S.D. Scientific
Related Party Transaction [Line Items]
Ownership percentage	50.00%
Affiliated Entity | Series A-1 Preferred Stock
Related Party Transaction [Line Items]
Number of shares issued during period			31,546
Value of stock issued			$ 100
Affiliated Entity | Series A-1A Preferred Stock
Related Party Transaction [Line Items]
Number of shares issued during period			15,773
Value of stock issued			$ 50
Affiliated Entity | S.D. Scientific | Consulting Fees
Related Party Transaction [Line Items]
Expenses paid on behalf of Company	$ 0	$ 0	$ 54

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	$ 25,137	$ 13,213
Unrecognized tax benefits that would impact the effective tax rate	1,034
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	48,289
Federal | Research tax credit carryover
Operating Loss Carryforwards [Line Items]
Tax credit carryovers	1,614
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers	48,158
State | Research tax credit carryover
Operating Loss Carryforwards [Line Items]
Tax credit carryovers	$ 1,472

Income Taxes - Reconciliation S

Income Taxes - Reconciliation Statutory Federal Income Tax to Effective Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income tax expense (benefit) at statutory federal rate	$ (9,226)	$ (9,227)	$ (1,432)
State income tax, net of federal benefit	(1,678)	(1,663)	(245)
Permanent items	58	14	2
Research credits	(1,379)	(807)	(188)
Stock compensation	0	0	6
ASC 740-10	552	323	75
Change in valuation allowance	11,924	11,388	1,782
Other individually immaterial items	(251)	(28)	0
Provision (benefit) for income taxes	$ 0	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income tax expense (benefit) at statutory federal rate	34.00%	34.00%	34.00%
State income tax, net of federal benefit	6.20%	6.10%	5.80%
Permanent items	(0.20%)	(0.10%)	0.00%
Research credits	5.10%	3.00%	4.50%
Stock compensation	0.00%	0.00%	(0.10%)
ASC 740-10	(2.00%)	(1.20%)	(1.80%)
Change in valuation allowance	(43.90%)	(41.90%)	(42.40%)
Other individually immaterial items	0.80%	0.10%	0.00%
Provision (benefit) for income taxes	0.00%	0.00%	0.00%

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss carryforwards	$ 19,173	$ 10,047
Research & development credits	1,591	597
Accrued expenses	766	463
Amortization and depreciation	(38)	4
Other	2	1
Stock-based compensation	3,643	2,101
Deferred tax assets, gross	25,137	13,213
Valuation Allowance	(25,137)	(13,213)
Net current deferred tax assets	$ 0	$ 0

Income Taxes - Rollforward of C

Income Taxes - Rollforward of Changes in Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 473	$ 91
Additions based on tax positions related to the current year	650	382
Additions for tax positions of prior years	111	0
Balance at end of year	$ 1,234	$ 473

Net Loss Per Share (Details)

Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net loss attributable to common stockholders	$ (6,420)	$ (7,095)	$ (6,883)	$ (6,732)	$ (6,789)	$ (6,072)	$ (8,110)	$ (6,168)	$ (27,130)	$ (27,139)	$ (4,213)
Denominator:
Weighted-average number of common shares outstanding, basic and diluted	19,816,000	19,792,000	19,756,000	19,726,000	19,719,000	19,713,000	19,426,000	16,222,000	19,773,000	18,782,000	3,732,000
Net loss per common share attributable to common stockholders, basic and diluted	$ (0.32)	$ (0.36)	$ (0.35)	$ (0.34)	$ (0.34)	$ (0.31)	$ (0.42)	$ (0.38)	$ (1.37)	$ (1.44)	$ (1.13)
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS computation									3,116,185	2,329,415	1,375,914

Employee Savings Plan (Details)

Employee Savings Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Employee savings plan
Defined Contribution Plan Disclosure [Line Items]
Maximum contributions per employee, percent of salary	90.00%
Employer matching contribution, percent of match	50.00%
Employer matching contribution, percent of participant's compensation	6.00%
Contributions during the year	$ 164	$ 84
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match	3.00%

Selected Quarterly Financial 55

Selected Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating costs and expenses
Research and development	$ 4,579	$ 5,033	$ 4,991	$ 4,809	$ 4,802	$ 3,755	$ 5,639	$ 4,498	$ 19,412	$ 18,694	$ 3,140
General and administrative	1,881	2,095	1,921	1,953	2,014	2,342	2,504	1,679	7,850	8,539	1,079
Total operating cost and expenses	6,460	7,128	6,912	6,762	6,816	6,097	8,143	6,177	27,262	27,233	4,219
Loss from operations	(6,460)	(7,128)	(6,912)	(6,762)	(6,816)	(6,097)	(8,143)	(6,177)	(27,262)	(27,233)	(4,219)
Interest and other income, net	40	33	29	30	27	25	33	9	132	94	6
Net loss	$ (6,420)	$ (7,095)	$ (6,883)	$ (6,732)	$ (6,789)	$ (6,072)	$ (8,110)	$ (6,168)	$ (27,130)	$ (27,139)	$ (4,213)
Net loss per share, basic and diluted	$ (0.32)	$ (0.36)	$ (0.35)	$ (0.34)	$ (0.34)	$ (0.31)	$ (0.42)	$ (0.38)	$ (1.37)	$ (1.44)	$ (1.13)
Weighted-average number of common shares outstanding, basic and diluted	19,816	19,792	19,756	19,726	19,719	19,713	19,426	16,222	19,773	18,782	3,732

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands	Jan. 11, 2016USD ($)position	Feb. 03, 2016USD ($)ft²	Dec. 31, 2015USD ($)	Nov. 30, 2015ft²	Aug. 31, 2015ft²	Jan. 31, 2015ft²	Jan. 14, 2015ft²
Subsequent Event [Line Items]
Total expected rent payments | $			$ 1,134
Operating Lease | Laboratory space
Subsequent Event [Line Items]
Additional area of real estate property				123	131	2,431	3,599
Area of real estate property					3,126
Subsequent Event
Subsequent Event [Line Items]
Number of positions eliminated | position	18
Restructuring costs | $	$ 655
Subsequent Event | Operating Lease | Laboratory space
Subsequent Event [Line Items]
Additional area of real estate property		3,599
Area of real estate property		8,429
Total expected rent payments | $		$ 189