Kindred Biosciences (KIN) 10-K 1 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Feb. 28, 2017	Jun. 30, 2016
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	Non-accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding (in shares)		22,070,218
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 49.8

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 6,687	$ 19,992
Short-term investments	50,068	53,051
Prepaid expenses and other	1,282	712
Total current assets	58,037	73,755
Property and equipment, net	2,441	1,244
Long-term investments	1,052	4,590
Other assets	46	30
Total assets	61,576	79,619
Current liabilities:
Accounts payable	410	717
Accrued compensation	1,807	1,922
Accrued liabilities	1,650	569
Total current liabilities	3,867	3,208
Long-term liability	29	40
Total liabilities	3,896	3,248
Commitments and contingencies (Note 9)
Stockholders’ equity:
Common stock; $0.0001 par value; 100,000,000 shares authorized; 19,916,290 shares and 19,836,360 shares issued and outstanding at December 31, 2016 and 2015, respectively	2	2
Additional paid-in capital	138,810	135,021
Accumulated other comprehensive loss	(31)	(50)
Accumulated deficit	(81,101)	(58,602)
Total stockholders’ equity	57,680	76,371
Total liabilities and stockholders’ equity	$ 61,576	$ 79,619

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Common stock, par value (USD per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	19,916,290	19,836,360
Common stock, shares outstanding (in shares)	19,916,290	19,836,360

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating expenses:
Research and development	$ 3,509	$ 3,754	$ 3,161	$ 3,437	$ 4,579	$ 5,033	$ 4,991	$ 4,809	$ 13,861	$ 19,412	$ 18,694
General and administrative	2,401	2,022	1,865	2,020	1,881	2,095	1,921	1,953	8,308	7,850	8,539
Restructuring costs	0	0	0	655	0	0	0	0	655	0	0
Total operating expenses	5,910	5,776	5,026	6,112	6,460	7,128	6,912	6,762	22,824	27,262	27,233
Loss from operations	(5,910)	(5,776)	(5,026)	(6,112)	(6,460)	(7,128)	(6,912)	(6,762)	(22,824)	(27,262)	(27,233)
Interest and other income, net	101	93	79	52	40	33	29	30	325	132	94
Net loss	$ (5,809)	$ (5,683)	$ (4,947)	$ (6,060)	$ (6,420)	$ (7,095)	$ (6,883)	$ (6,732)	(22,499)	(27,130)	(27,139)
Change in unrealized gains or losses on available-for-sale securities									19	(23)	(27)
Comprehensive loss									$ (22,480)	$ (27,153)	$ (27,166)
Net loss per share, basic and diluted (USD per share)	$ (0.29)	$ (0.29)	$ (0.25)	$ (0.31)	$ (0.32)	$ (0.36)	$ (0.35)	$ (0.34)	$ (1.13)	$ (1.37)	$ (1.44)
Weighted-average number of common shares outstanding, basic and diluted (in shares)	19,900	19,891	19,865	19,836	19,816	19,792	19,756	19,726	19,873	19,773	18,782

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2013		16,214,000
Beginning balance at Dec. 31, 2013	$ 63,279	$ 2	$ 67,610	$ 0	$ (4,333)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(27,139)				(27,139)
Change in unrealized gains or losses on available-for-sale securities	(27)			(27)
Comprehensive loss	(27,166)
Stock-based compensation	4,725		4,725
Issuance of common stock at secondary public offering, net of offering costs of $4,035 (in shares)		3,450,000
Issuance of common stock at secondary public offering, net of offering costs of $4,035	$ 58,065		58,065
Exercise of common stock options (in shares)	56,112	56,000
Exercise of common stock options	$ 121		121
Vesting of restricted stock (in shares)		4,000
Vesting of restricted stock	0
Ending balance (in shares) at Dec. 31, 2014		19,724,000
Ending balance at Dec. 31, 2014	99,024	$ 2	130,521	(27)	(31,472)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(27,130)				(27,130)
Change in unrealized gains or losses on available-for-sale securities	(23)			(23)
Comprehensive loss	(27,153)
Stock-based compensation	$ 4,157		4,157
Exercise of common stock options (in shares)	58,126	58,000
Exercise of common stock options	$ 105		105
Common stock issued under ESPP (in shares)		53,752
Common stock issued under ESPP	$ 238		238
Ending balance (in shares) at Dec. 31, 2015	19,836,360	19,836,000
Ending balance at Dec. 31, 2015	$ 76,371	$ 2	135,021	(50)	(58,602)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(22,499)				(22,499)
Change in unrealized gains or losses on available-for-sale securities	19			19
Comprehensive loss	(22,480)
Stock-based compensation	$ 3,627		3,627
Exercise of common stock options (in shares)	39,501	40,000
Exercise of common stock options	$ 23		23
Common stock issued under ESPP (in shares)		40,429
Common stock issued under ESPP	$ 139		139
Ending balance (in shares) at Dec. 31, 2016	19,916,290	19,916,000
Ending balance at Dec. 31, 2016	$ 57,680	$ 2	$ 138,810	$ (31)	$ (81,101)

Consolidated Statements of Sto6

Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Apr. 30, 2014	Dec. 31, 2015
Common Stock
Payments of offering costs	$ 4,035	$ 4,035

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows from Operating Activities
Net loss	$ (22,499)	$ (27,130)	$ (27,139)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	3,627	4,157	4,422
Depreciation and amortization expense	155	146	58
Loss on disposal of property and equipment	3	0	0
Amortization of premium on marketable securities	274	228	87
Changes in operating assets and liabilities:
Prepaid expenses and other	(570)	(235)	(329)
Other assets	(16)	(8)	(22)
Accounts payable	(710)	30	(269)
Accrued liabilities and accrued compensation	955	55	1,258
Net cash used in operating activities	(18,781)	(22,757)	(21,934)
Cash Flows from Investing Activities
Purchase of investments	(72,047)	(102,195)	(145,172)
Sale of investments	0	3,000	9,000
Maturities of investments	78,313	129,361	48,000
Purchase of property and equipment	(952)	(729)	(440)
Net cash provided by (used in) investing activities	5,314	29,437	(88,612)
Cash Flows from Financing Activities
Exercise of stock options and purchase of ESPP shares	162	343	121
Net proceeds from follow-on public offering	0	0	58,065
Net cash provided by financing activities	162	343	58,186
Net change in cash and cash equivalents	(13,305)	7,023	(52,360)
Cash and cash equivalents at beginning of year	19,992	12,969	65,329
Cash and cash equivalents at end of year	6,687	19,992	12,969
Supplemental disclosure of non-cash financing activities:
Purchase of property and equipment included in accounts payable and accrued liabilities	670	267	0
Common Stock
Supplemental disclosure of non-cash financing activities:
Issuance of common stock and stock options for accrued consulting expenses	$ 0	$ 0	$ 303

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2016
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. On April 25, 2016, we filed a Certificate of Incorporation with the State of Delaware for a wholly owned subsidiary, KindredBio Equine, Inc. ("Subsidiary"). The Subsidiary has one class of capital stock which is designated common stock, $0.0001 par value per share. The authorized number of shares of common stock for the Subsidiary is 1,000 . 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 $81,101,000 as of December 31, 2016. 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. In December 2016, we entered into an At Market Issuance Sales Agreement with FBR Capital Markets & Co., or FBR, whereby we may issue and sell shares of our common stock having an aggregate offering price up to $30.0 million , from time to time. Through February 28, 2017, we sold 1,895,428 shares through FBR under the sales agreement and received approximately $11,465,000 in net proceeds after deducting commissions and other related expenses. We believe our cash, cash equivalents, short-term and long-term investments of $57,807,000 at December 31, 2016 along with the proceeds from our ATM sales are sufficient to fund our operations through the end of 2018. 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, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of the Company and its wholly owned Subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of consolidated 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 consolidated financial statements, and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated 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 consolidated 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 consolidated 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 Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash, cash equivalents and investments. From time to time, we maintain cash and cash equivalent balances in excess of amounts insured by the Federal Deposit Insurance Corporation (“FDIC”) and the Securities Investor Protection Corporation ("SIPC"). Primarily all of our cash, cash equivalents and investments at December 31, 2016 were in excess of amounts insured by the FDIC and SIPC. 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, corporate notes and commercial papers are recorded at their estimated fair value. Since these available-for-sale 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 no t 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 8) 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 consolidated statements 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 consolidated 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 consolidated 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 consolidated 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 consolidated 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 12). Recently Issued Accounting Pronouncements In May 2014, FASB issued Accounting Standards Update (ASU) No. 2014-09, "Revenue from Contracts with Customers". This new standard will replace most of the existing revenue recognition guidance in U.S. GAAP when it becomes effective and permits the use of either the retrospective or cumulative effect transition method. The new standard, as amended, becomes effective in the first quarter of fiscal year 2018, but allows the adoption of the standard one year earlier if we so choose. To-date we do not have any revenue, but we continue to assess the effect of this new standard. In August 2014, the FASB issued ASU No. 2014-15, "Presentation of Financial Statements—Going Concern Disclosure of Uncertainties About an Entity's Ability to Continue as a Going Concern", which requires management to evaluate whether there are conditions or events that raise substantial doubt about an entity's ability to continue as a going concern and to provide disclosures when certain criteria are met. The guidance is effective for annual periods ending after December 15, 2016 and interim reporting periods starting in the first quarter of 2017. We adopted this standard as of December 31, 2016. 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 consolidated 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 noncurrent deferred tax asset or liability in each jurisdiction and allocate valuation allowances. The update is effective for public business entities issuing consolidated consolidated financial statements for the annual periods beginning after December 15, 2016, and interim periods within those annual periods. We have evaluated the new guidance and determined the impact of this standard have no effects on our consolidated 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 consolidated 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 consolidated 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 consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, “Improvements to Employee Share-Based Payment Accounting”, which amends ASC Topic 718, “Compensation - Stock Compensation”. The ASU includes provisions intended to simplify various aspects related to how share-based payments are accounted for and presented in the consolidated financial statements. ASU 2016-09 is effective for public business entities for annual reporting periods beginning after December 15, 2016, and interim periods within that reporting period. Early adoption will be permitted in any interim or annual period, with any adjustments reflected as of the beginning of the fiscal year of adoption. Our early adoption of this standard in 2016 did not have a material impact on our consolidated financial statements. We do not believe there are any other recently issued standards not yet effective that will have a material impact on our consolidated financial statements when the standards become effective.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
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, 2016 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, 2016 Description Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Cash equivalents: Money market funds $ 3,157 $ 3,157 $ — $ — Commercial paper 850 — 850 — Short-term investments: U.S. treasury bills 5,997 5,997 — — Commercial paper 4,228 — 4,228 — U.S. government agency notes 13,550 — 13,550 — U.S. treasury bonds and notes 11,015 11,015 — — Corporate notes 15,278 — 15,278 — Long-term investments: Corporate notes 1,052 — 1,052 — $ 55,127 $ 20,169 $ 34,958 $ — 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 $ — During the year ended December 31, 2016 , U.S. treasuries were transferred from Level 2 to Level 1. With the exception of U.S. treasuries, there were no other transfers of assets between Level 1, Level 2 or Level 3 of the fair value hierarchy during the years ended December 31, 2016 and 2015 . At December 31, 2016 and 2015 , we did not have any financial liabilities which were measured at fair value on a recurring basis.

Investments

Investments	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
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, 2016 and 2015 (in thousands): December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term investments: U.S. treasury bills $ 5,996 $ 1 $ — $ 5,997 Commercial paper 4,228 — — 4,228 U.S. government agency notes 13,552 1 (3 ) 13,550 U.S. treasury bonds and notes 11,015 1 (1 ) 11,015 Corporate notes 15,305 — (27 ) 15,278 50,096 3 (31 ) 50,068 Long-term investments: Corporate notes 1,055 — (3 ) 1,052 Total available-for-sale investments $ 51,151 $ 3 $ (34 ) $ 51,120 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 The following table summarizes the contractual maturities of our available-for-sale securities at December 31, 2016 (in thousands): Amortized Cost Fair Value Mature in less than one year $ 50,096 $ 50,068 Mature in one year or more $ 1,055 $ 1,052

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2016
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) 2016 2015 Computer and lab equipment $ 565 $ 437 Furniture & fixtures 41 38 Leasehold improvements 82 78 Construction-in-process 2,073 895 Total 2,761 1,448 Less accumulated depreciation and amortization (320 ) (204) Property and equipment, net $ 2,441 $ 1,244 Depreciation and amortization expense was $155,000 , $146,000 and $58,000 for the years ended December 31, 2016 , 2015 and 2014 , respectively.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities consisted of the following as of December 31, 2016 and 2015 : (In thousands) December 31, 2016 December 31, 2015 Accrued consulting $ 106 $ 83 Accrued research and development costs 1,390 345 Accrued other 124 128 Deferred rent 59 53 1,679 609 Less current portion (1,650 ) (569 ) Long-term liability (deferred rent) $ 29 $ 40

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Preferred Stock Our Certificate of Incorporation, as amended, authorizes us to issue 10,000,000 shares of $0.0001 par value preferred stock. At December 31, 2016 , all shares of preferred stock are undesignated and unissued. 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 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 . In 2016, we issued 39,501 shares of common stock upon exercise of stock options at prices ranging from $0.32 to $1.37 per share for total proceeds of $23,000 . In addition, we issued 40,429 shares of common stock to employees in connection with our employee stock purchase program for total proceeds of $139,000 . As of December 31, 2016 , we had 19,916,290 shares of common stock outstanding. Stock Offerings In January 2015, we filed a shelf registration statement on Form S-3 to offer and sell, from time to time, equity and debt securities in one or more offerings up to a total dollar amount of $150.0 million . On December 19, 2016, we entered into an At Market Issuance Sales Agreement with FBR Capital Markets & Co., or FBR, pursuant to which we may issue and sell shares of our common stock having an aggregate offering price up to $30.0 million , from time to time, through FBR as our sales agent. In conjunction with the sales agreement, FBR will receive compensation based on an aggregate of 3% of the gross proceeds on the sale price per share of our common stock. Any sales made pursuant to the sales agreement are deemed an “at-the-market” offering and would be made pursuant to the shelf registration statement on Form S-3. For the year ended December 31, 2016, we did not sell any shares through FBR under the sales agreement (see Note 15).

Stock-Based Awards and Benefit

Stock-Based Awards and Benefit Plan	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Awards and Benefit Plan	Stock-Based Awards and Benefit Plan On November 4, 2012, our board of directors adopted the Kindred Biosciences, Inc. 2012 Equity Incentive Plan or 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. The 2012 Plan terminated in May 2016. There were 3,495,979 stock option shares which had been granted prior to the plan’s expiration remaining outstanding as of December 31, 2016. In May 2016, we adopted the 2016 Equity Incentive Plan or the “2016 Plan”, and reserved 3,000,000 shares of our common stock for issuance under the 2016 Plan. The 2016 Plan is the successor to our 2012 Plan and all awards made under the 2012 Plan shall remain subject to the terms of that plan. Options granted under the 2016 Plan may be either incentive stock options or nonstatutory stock options. The 2016 Plan also provides for the grant of stock appreciation rights, restricted stock awards, restricted stock unit awards, performance stock awards, performance cash awards and other stock awards. The exercise price of a stock option may not be less than 100% of the closing price of our common stock on the date of the grant. If, at any time we grant an option, and the optionee directly or by attribution owns stock possessing more than 10% of the total combined voting power of all classes of our stock, the option price shall be at least 110% of the fair value and shall not be exercisable more than five years after the date of grant. Options generally vest over a period of one or four years from the date of grant. Options granted under the 2016 Plan expire no later than 10 years from the date of grant. As of December 31, 2016, there were 72,350 option shares outstanding and 2,927,650 shares available for future grants under the 2016 Plan. 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 $1.42 during the year ended December 31, 2016 . As of December 31, 2016 , there were 94,181 shares of common stock issued under the Purchase Plan and 105,819 shares available for future issuance under the Purchase Plan. At December 31, 2016 , we had an outstanding liability of $17,000 , which is included in accrued compensation on the consolidated 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, 2016 , shares of common stock reserved for future issuance inclusive of outstanding option shares are as follows: 2016 Equity Incentive Plan 3,000,000 2014 Employee Stock Purchase Plan 105,819 3,105,819 Stock Option Plan Activity Summary A summary of activity under our stock option plans 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, 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 2012 Plan terminated (a) (307,107 ) 2016 Plan authorized (b) 3,000,000 Granted (847,683 ) 847,683 $ 3.48 Exercised (39,501 ) $ 0.57 Expired 43,818 (43,818 ) $ 14.52 Forfeited - stock options 312,220 (312,220 ) $ 7.06 Balance, December 31, 2016 2,927,650 3,568,329 $ 6.36 7.5 $ 4,353,000 Options vested and expected to vest, December 31, 2016 3,568,329 $ 6.36 7.5 $ 4,353,000 Options exercisable, December 31, 2016 2,298,322 $ 6.50 7.0 $ 3,684,000 (a) The 2012 Equity Incentive Plan terminated in May 2016. All shares available for grant under this Plan expired. (b) The 2016 Equity Incentive Plan was adopted and approved by stockholders in May 2016. 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, 2016 and 2015. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2016 , 2015 and 2014 was $117,000 , $266,000 and $774,000 , respectively. We received proceeds of $23,000 , $105,000 and $121,000 from the exercise of common stock options during the years ended December 31, 2016 , 2015 and 2014, respectively. The weighted-average grant date fair value of options granted during the years ended December 31, 2016 , 2015 and 2014 was $2.45 , $5.03 and $12.09 per share, respectively. Restricted Stock We did not grant any restricted common stock in 2016, 2015 and 2014. As of December 31, 2016 , 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. The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes option-pricing model. Due to insufficient company-specific historical and implied volatility information, we estimate the expected stock price 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 common 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, 2016 2015 2014 Research and development $ 1,463 $ 1,857 $ 1,453 General and administrative 2,164 2,300 2,969 $ 3,627 $ 4,157 $ 4,422 Total stock-based compensation expense included stock options and expense from the Purchase Plan for the years ended December 31, 2016 and 2015, and stock options and restricted stock for the year ended December 31, 2014. We had an aggregate of approximately $5,179,455 of unrecognized stock-based compensation expense for options outstanding and the Purchase Plan as of December 31, 2016 , which is expected to be recognized over a weighted average period of 1.9 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, 2016 2015 2014 Stock options: Weighted average risk-free interest rate 1.61% 1.51% 1.70% Weighted average expected term (in years) 6.3 6.1 6.4 Weighted average expected volatility 83.4% 94.8% 91.3% Weighted average expected dividend yield — — — Employee stock purchase plan: Weighted average risk-free interest rate 0.50% 0.08% — Weighted average expected term (in years) 0.5 0.5 0 Weighted average expected volatility 84.4% 80.7% — Weighted average expected dividend yield — — —

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
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 2,145 square feet of laboratory space through May 2017 and 6,900 square feet of 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 and October 2016, we further amended our original operating lease for laboratory space to further expand the facility with an additional 3,599 square feet and 2,326 square feet, respectively, of laboratory space through May 2017. Commencing on June 1, 2017, the non-cancellable operating lease for the entire existing laboratory space of a total 10,755 square feet is extended for another 5 years through May 2022. In February 2017, we further amended the operating lease for laboratory space with an additional 721 square feet through May 2022. In addition, we have three equipment leases expiring through 2020. Rent expense for the years ended December 31, 2016 , 2015 and 2014 was $522,000 , $339,000 and $162,000 , respectively. In addition, we have three operating leases for equipment through 2020. As of December 31, 2016, we are obligated to make minimum lease payments under all of our operating leases, including the amendment entered into in February 2017 (see Note 15), as follows (in thousands): Year ending December 31, Lease Payments 2017 $ 670 2018 523 2019 513 2020 448 2021 459 Thereafter 194 Total $ 2,807 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 consolidated 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 consolidated financial position and results of operations.

Restructuring Plan

Restructuring Plan	12 Months Ended
	Dec. 31, 2016
Restructuring and Related Activities [Abstract]
Restructuring Plan	Restructuring Plan On January 8, 2016, our Board of Directors committed to a restructuring plan intended to better align our workforce to our revised operating needs and program development plans. On January 11, 2016, we implemented the restructuring plan that focused on streamlining our development programs and to ensure our remaining funds are sufficient to fund our planned operations through 2018. To match these priorities, we reduced our workforce by 18 positions, or approximately 31% of our workforce, resulting in a total workforce of 39 positions. As a result of the restructuring plan which has been completed, we recorded a restructuring charge of approximately $655,000 related to severance payments which was entirely paid in the quarter ended March 31, 2016. There were no further restructuring charges since then.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
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, 2016 2015 2014 Income tax expense (benefit) at statutory federal rate $ (7,651 ) 34.0 % $ (9,226 ) 34.0 % $ (9,227 ) 34.0 % State income tax, net of federal benefit (1,389 ) 6.2 (1,678 ) 6.2 (1,663 ) 6.1 Permanent items 38 (0.2 ) 58 (0.2 ) 14 (0.1 ) Research credits (970 ) 4.3 (1,379 ) 5.1 (807 ) 3 Stock-based compensation (29 ) 0.1 — — — — ASC 740-10 388 (1.7 ) 552 (2 ) 323 (1.2 ) Change in valuation allowance 9,602 (42.6 ) 11,924 (43.9 ) 11,388 (41.9 ) Other 11 (0.1 ) (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, 2016 and 2015 : December 31, (In thousands) 2016 2015 Deferred tax assets: Net operating loss carryforwards $ 27,093 $ 19,173 Research & development credits 2,173 1,591 Accrued expenses 720 766 Amortization and depreciation 2,738 (38 ) Stock-based compensation 2,296 3,643 Other 14 2 35,034 25,137 Valuation Allowance (35,034 ) (25,137 ) Net current deferred tax assets $ — $ — At December 31, 2016 , we had net deferred tax assets of $35,034,000 . 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 ownership changes since 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, 2016. At December 31, 2016 , we had federal and California net operating loss carryovers of $67,305,000 and $67,202,000 , respectively. The federal and California net loss carryforwards will begin to expire in 2032. At December 31, 2016 , we had federal and state research tax credit carryovers of approximately $2,215,000 and $2,031,000 , 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, 2016 2015 Balance at beginning of year $ 1,234 $ 473 Additions based on tax positions related to the current year 464 650 Additions for tax positions of prior years — 111 Balance at end of year $ 1,698 $ 1,234 The amount of unrecognized tax benefits that would impact the effective tax rate if recognized and realized is $1,422,000 . 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 consolidated balance sheets at December 31, 2016 and 2015 , and have not recognized interest and/or penalties in our consolidated statements of operations and comprehensive loss for the years ended December 31, 2016 , 2015 and 2014 . 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. In March 2016, the FASB issued ASU No. 2016-09, "Improvements to Employee Share-Based Payment Accounting". Current GAAP requires an entity to recognize excess tax benefit or deficiency as additional paid-in capital. To simplify the presentation of stock compensation, the amendments in this Update require that the excess tax benefit or deficiency is recognized as expense. For public business entities, the amendments in this Update are effective for financial statements issued for annual periods beginning after December 15, 2016 and interim periods within those annual periods. The FASB permits earlier application by all entities as of the beginning of any interim or annual reporting period and further provides that this Update may be applied on a modified retrospective basis to all periods presented. We chose to adopt the update prospectively beginning in the year ended December 31, 2016. Prior periods have not been retrospectively adjusted, and given our full valuation position there is no quantitative impact to our consolidated financial statements.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2016
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, 2016 , 2015 and 2014: (In thousands, except per share amounts) Years Ended December 31, 2016 2015 2014 Basic and diluted net loss per share attributable to common stockholders: Numerator: Net loss attributable to common stockholders $ (22,499 ) $ (27,130 ) $ (27,139 ) Denominator: Weighted-average number of common shares outstanding, basic and diluted 19,873 19,773 18,782 Net loss per common share attributable to common stockholders, basic and diluted $ (1.13 ) $ (1.37 ) $ (1.44 ) There was no difference between our net loss and the net loss attributable to common stockholders for all periods presented. Stock options to purchase 3,568,329 shares, 3,116,185 shares and 2,329,415 shares of common stock as of December 31, 2016 , 2015 and 2014 , 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, 2016
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 $101,000 and $164,000 to the plan during the years ended December 31, 2016 and 2015 , respectively.

Selected Quarterly Financial In

Selected Quarterly Financial Information (unaudited)	12 Months Ended
	Dec. 31, 2016
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, 2016 and 2015 . (In thousands, except per share amounts) 2016 2015 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 $ 3,509 $ 3,754 $ 3,161 $ 3,437 $ 4,579 $ 5,033 $ 4,991 $ 4,809 General and administrative 2,401 2,022 1,865 2,020 1,881 2,095 1,921 1,953 Restructuring costs — — — 655 — — — — Total operating cost and expenses 5,910 5,776 5,026 6,112 6,460 7,128 6,912 6,762 Loss from operations (5,910 ) (5,776 ) (5,026 ) (6,112 ) (6,460 ) (7,128 ) (6,912 ) (6,762 ) Interest and other income, net 101 93 79 52 40 33 29 30 Net loss $ (5,809 ) $ (5,683 ) $ (4,947 ) $ (6,060 ) $ (6,420 ) $ (7,095 ) $ (6,883 ) $ (6,732 ) Net loss per share, basic and diluted (1) $ (0.29 ) $ (0.29 ) $ (0.25 ) $ (0.31 ) $ (0.32 ) $ (0.36 ) $ (0.35 ) $ (0.34 ) Weighted average shares used in computing net loss per share, basic and diluted 19,900 19,891 19,865 19,836 19,816 19,792 19,756 19,726 (1) Net loss per share for each quarter is 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, 2016
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 December 19, 2016, we entered into an At Market Issuance Sales Agreement with FBR Capital Markets & Co., or FBR, pursuant to which we may issue and sell shares of our common stock having an aggregate offering price up to $30.0 million , from time to time, through FBR as our sales agent. In conjunction with the sales agreement, FBR would receive compensation based on an aggregate of 3% of the gross proceeds on the sale price per share of our common stock. Through February 28, 2017, we sold 1,895,428 shares through FBR under the sales agreement and received approximately $11,465,000 in net proceeds after deducting commissions and other related expenses. On February 14, 2017, 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 721 square feet of laboratory space for a total of 11,476 square feet. The term of the lease is April 1, 2017 through May 31, 2022 and total rent payments from this amendment are expected to be $142,000 .

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Liquidity	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 $81,101,000 as of December 31, 2016. 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. In December 2016, we entered into an At Market Issuance Sales Agreement with FBR Capital Markets & Co., or FBR, whereby we may issue and sell shares of our common stock having an aggregate offering price up to $30.0 million , from time to time. Through February 28, 2017, we sold 1,895,428 shares through FBR under the sales agreement and received approximately $11,465,000 in net proceeds after deducting commissions and other related expenses. We believe our cash, cash equivalents, short-term and long-term investments of $57,807,000 at December 31, 2016 along with the proceeds from our ATM sales are sufficient to fund our operations through the end of 2018. 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.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of the Company and its wholly owned Subsidiary. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of consolidated 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 consolidated financial statements, and the reported amounts of revenues and expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated 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	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 consolidated 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 consolidated 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 Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash, cash equivalents and investments. From time to time, we maintain cash and cash equivalent balances in excess of amounts insured by the Federal Deposit Insurance Corporation (“FDIC”) and the Securities Investor Protection Corporation ("SIPC"). Primarily all of our cash, cash equivalents and investments at December 31, 2016 were in excess of amounts insured by the FDIC and SIPC. 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, corporate notes and commercial papers are recorded at their estimated fair value. Since these available-for-sale 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). 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.
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 no t 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 8) 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 consolidated statements 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 consolidated 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 consolidated 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 consolidated 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 consolidated 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 12).
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In May 2014, FASB issued Accounting Standards Update (ASU) No. 2014-09, "Revenue from Contracts with Customers". This new standard will replace most of the existing revenue recognition guidance in U.S. GAAP when it becomes effective and permits the use of either the retrospective or cumulative effect transition method. The new standard, as amended, becomes effective in the first quarter of fiscal year 2018, but allows the adoption of the standard one year earlier if we so choose. To-date we do not have any revenue, but we continue to assess the effect of this new standard. In August 2014, the FASB issued ASU No. 2014-15, "Presentation of Financial Statements—Going Concern Disclosure of Uncertainties About an Entity's Ability to Continue as a Going Concern", which requires management to evaluate whether there are conditions or events that raise substantial doubt about an entity's ability to continue as a going concern and to provide disclosures when certain criteria are met. The guidance is effective for annual periods ending after December 15, 2016 and interim reporting periods starting in the first quarter of 2017. We adopted this standard as of December 31, 2016. 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 consolidated 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 noncurrent deferred tax asset or liability in each jurisdiction and allocate valuation allowances. The update is effective for public business entities issuing consolidated consolidated financial statements for the annual periods beginning after December 15, 2016, and interim periods within those annual periods. We have evaluated the new guidance and determined the impact of this standard have no effects on our consolidated 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 consolidated 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 consolidated 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 consolidated financial statements. In March 2016, the FASB issued ASU No. 2016-09, “Improvements to Employee Share-Based Payment Accounting”, which amends ASC Topic 718, “Compensation - Stock Compensation”. The ASU includes provisions intended to simplify various aspects related to how share-based payments are accounted for and presented in the consolidated financial statements. ASU 2016-09 is effective for public business entities for annual reporting periods beginning after December 15, 2016, and interim periods within that reporting period. Early adoption will be permitted in any interim or annual period, with any adjustments reflected as of the beginning of the fiscal year of adoption. Our early adoption of this standard in 2016 did not have a material impact on our consolidated financial statements. We do not believe there are any other recently issued standards not yet effective that will have a material impact on our consolidated financial statements when the standards become effective.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 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, 2016 Description Total Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Unobservable Inputs (Level 3) Cash equivalents: Money market funds $ 3,157 $ 3,157 $ — $ — Commercial paper 850 — 850 — Short-term investments: U.S. treasury bills 5,997 5,997 — — Commercial paper 4,228 — 4,228 — U.S. government agency notes 13,550 — 13,550 — U.S. treasury bonds and notes 11,015 11,015 — — Corporate notes 15,278 — 15,278 — Long-term investments: Corporate notes 1,052 — 1,052 — $ 55,127 $ 20,169 $ 34,958 $ — 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 $ —

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 and 2015 (in thousands): December 31, 2016 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Short-term investments: U.S. treasury bills $ 5,996 $ 1 $ — $ 5,997 Commercial paper 4,228 — — 4,228 U.S. government agency notes 13,552 1 (3 ) 13,550 U.S. treasury bonds and notes 11,015 1 (1 ) 11,015 Corporate notes 15,305 — (27 ) 15,278 50,096 3 (31 ) 50,068 Long-term investments: Corporate notes 1,055 — (3 ) 1,052 Total available-for-sale investments $ 51,151 $ 3 $ (34 ) $ 51,120 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 The following table summarizes the contractual maturities of our available-for-sale securities at December 31, 2016 (in thousands): Amortized Cost Fair Value Mature in less than one year $ 50,096 $ 50,068 Mature in one year or more $ 1,055 $ 1,052

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment, Net [Abstract]
Schedule of property and equipment	Property and equipment consisted of the following: As of December 31, (in thousands) 2016 2015 Computer and lab equipment $ 565 $ 437 Furniture & fixtures 41 38 Leasehold improvements 82 78 Construction-in-process 2,073 895 Total 2,761 1,448 Less accumulated depreciation and amortization (320 ) (204) Property and equipment, net $ 2,441 $ 1,244

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Payables and Accruals [Abstract]
Schedule of accrued liabilities	Accrued liabilities consisted of the following as of December 31, 2016 and 2015 : (In thousands) December 31, 2016 December 31, 2015 Accrued consulting $ 106 $ 83 Accrued research and development costs 1,390 345 Accrued other 124 128 Deferred rent 59 53 1,679 609 Less current portion (1,650 ) (569 ) Long-term liability (deferred rent) $ 29 $ 40

Stock-Based Awards and Benefi28

Stock-Based Awards and Benefit Plan (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of shares of common stock reserved for future issuance	At December 31, 2016 , shares of common stock reserved for future issuance inclusive of outstanding option shares are as follows: 2016 Equity Incentive Plan 3,000,000 2014 Employee Stock Purchase Plan 105,819 3,105,819
Summary of activity under stock option plans	A summary of activity under our stock option plans 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, 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 2012 Plan terminated (a) (307,107 ) 2016 Plan authorized (b) 3,000,000 Granted (847,683 ) 847,683 $ 3.48 Exercised (39,501 ) $ 0.57 Expired 43,818 (43,818 ) $ 14.52 Forfeited - stock options 312,220 (312,220 ) $ 7.06 Balance, December 31, 2016 2,927,650 3,568,329 $ 6.36 7.5 $ 4,353,000 Options vested and expected to vest, December 31, 2016 3,568,329 $ 6.36 7.5 $ 4,353,000 Options exercisable, December 31, 2016 2,298,322 $ 6.50 7.0 $ 3,684,000 (a) The 2012 Equity Incentive Plan terminated in May 2016. All shares available for grant under this Plan expired. (b) The 2016 Equity Incentive Plan was adopted and approved by stockholders in May 2016.
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, 2016 2015 2014 Research and development $ 1,463 $ 1,857 $ 1,453 General and administrative 2,164 2,300 2,969 $ 3,627 $ 4,157 $ 4,422
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, 2016 2015 2014 Stock options: Weighted average risk-free interest rate 1.61% 1.51% 1.70% Weighted average expected term (in years) 6.3 6.1 6.4 Weighted average expected volatility 83.4% 94.8% 91.3% Weighted average expected dividend yield — — — Employee stock purchase plan: Weighted average risk-free interest rate 0.50% 0.08% — Weighted average expected term (in years) 0.5 0.5 0 Weighted average expected volatility 84.4% 80.7% — Weighted average expected dividend yield — — —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments	As of December 31, 2016, we are obligated to make minimum lease payments under all of our operating leases, including the amendment entered into in February 2017 (see Note 15), as follows (in thousands): Year ending December 31, Lease Payments 2017 $ 670 2018 523 2019 513 2020 448 2021 459 Thereafter 194 Total $ 2,807

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 2015 2014 Income tax expense (benefit) at statutory federal rate $ (7,651 ) 34.0 % $ (9,226 ) 34.0 % $ (9,227 ) 34.0 % State income tax, net of federal benefit (1,389 ) 6.2 (1,678 ) 6.2 (1,663 ) 6.1 Permanent items 38 (0.2 ) 58 (0.2 ) 14 (0.1 ) Research credits (970 ) 4.3 (1,379 ) 5.1 (807 ) 3 Stock-based compensation (29 ) 0.1 — — — — ASC 740-10 388 (1.7 ) 552 (2 ) 323 (1.2 ) Change in valuation allowance 9,602 (42.6 ) 11,924 (43.9 ) 11,388 (41.9 ) Other 11 (0.1 ) (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, 2016 and 2015 : December 31, (In thousands) 2016 2015 Deferred tax assets: Net operating loss carryforwards $ 27,093 $ 19,173 Research & development credits 2,173 1,591 Accrued expenses 720 766 Amortization and depreciation 2,738 (38 ) Stock-based compensation 2,296 3,643 Other 14 2 35,034 25,137 Valuation Allowance (35,034 ) (25,137 ) 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, 2016 2015 Balance at beginning of year $ 1,234 $ 473 Additions based on tax positions related to the current year 464 650 Additions for tax positions of prior years — 111 Balance at end of year $ 1,698 $ 1,234

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 , 2015 and 2014: (In thousands, except per share amounts) Years Ended December 31, 2016 2015 2014 Basic and diluted net loss per share attributable to common stockholders: Numerator: Net loss attributable to common stockholders $ (22,499 ) $ (27,130 ) $ (27,139 ) Denominator: Weighted-average number of common shares outstanding, basic and diluted 19,873 19,773 18,782 Net loss per common share attributable to common stockholders, basic and diluted $ (1.13 ) $ (1.37 ) $ (1.44 )

Selected Quarterly Financial 32

Selected Quarterly Financial Information (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 and 2015 . (In thousands, except per share amounts) 2016 2015 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 $ 3,509 $ 3,754 $ 3,161 $ 3,437 $ 4,579 $ 5,033 $ 4,991 $ 4,809 General and administrative 2,401 2,022 1,865 2,020 1,881 2,095 1,921 1,953 Restructuring costs — — — 655 — — — — Total operating cost and expenses 5,910 5,776 5,026 6,112 6,460 7,128 6,912 6,762 Loss from operations (5,910 ) (5,776 ) (5,026 ) (6,112 ) (6,460 ) (7,128 ) (6,912 ) (6,762 ) Interest and other income, net 101 93 79 52 40 33 29 30 Net loss $ (5,809 ) $ (5,683 ) $ (4,947 ) $ (6,060 ) $ (6,420 ) $ (7,095 ) $ (6,883 ) $ (6,732 ) Net loss per share, basic and diluted (1) $ (0.29 ) $ (0.29 ) $ (0.25 ) $ (0.31 ) $ (0.32 ) $ (0.36 ) $ (0.35 ) $ (0.34 ) Weighted average shares used in computing net loss per share, basic and diluted 19,900 19,891 19,865 19,836 19,816 19,792 19,756 19,726 (1) Net loss per share for each quarter is calculated as a discrete period; the sum of four quarters may not equal the calculated full year amount.

Organization and Description 33

Organization and Description of Business (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 19, 2016	Feb. 28, 2017	Feb. 28, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Common stock, par value (USD per share)				$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)				100,000,000	100,000,000
Accumulated deficit				$ 81,101	$ 58,602
Maximum aggregate offering price of common stock sold under agreement	$ 30,000
Other Long-term Investments
Debt Instrument [Line Items]
Cash, cash equivalents, short-term and long-term investments				$ 57,807
KindredBio Equine, Inc
Debt Instrument [Line Items]
Common stock, par value (USD per share)				$ 0.0001
Common stock, shares authorized (in shares)				1,000
Subsequent Event
Debt Instrument [Line Items]
Net proceeds after deducting commissions and other related expenses		$ 11,465
Subsequent Event | FBR Capital Markets & Co.
Debt Instrument [Line Items]
Number of shares issued in transaction (in shares)			1,895,428

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2016USD ($)
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets to be disposed of	$ 0
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) - Financial assets measured at fair value on a recurring basis - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Fair Value Measurements
Total assets	$ 55,127,000	$ 70,195,000
Financial liabilities measured at fair value	0	0
Money market funds
Fair Value Measurements
Cash equivalents:	3,157,000	8,169,000
Commercial paper
Fair Value Measurements
Cash equivalents:	850,000
Short-term investments:	4,228,000
US Treasury Bill Securities [Member]
Fair Value Measurements
Short-term investments:	5,997,000
Long-term investments:		4,590,000
U.S. government agency notes
Fair Value Measurements
Cash equivalents:		4,385,000
Short-term investments:	13,550,000	11,769,000
U.S. treasury bills
Fair Value Measurements
Short-term investments:	11,015,000	41,282,000
Corporate notes
Fair Value Measurements
Short-term investments:	15,278,000
Long-term investments:	1,052,000
Quoted Prices in Active Markets (Level 1)
Fair Value Measurements
Total assets	20,169,000	8,169,000
Quoted Prices in Active Markets (Level 1) | Money market funds
Fair Value Measurements
Cash equivalents:	3,157,000	8,169,000
Quoted Prices in Active Markets (Level 1) | Commercial paper
Fair Value Measurements
Cash equivalents:	0
Short-term investments:	0
Quoted Prices in Active Markets (Level 1) | US Treasury Bill Securities [Member]
Fair Value Measurements
Short-term investments:	5,997,000
Long-term investments:		0
Quoted Prices in Active Markets (Level 1) | U.S. government agency notes
Fair Value Measurements
Cash equivalents:		0
Short-term investments:	0	0
Quoted Prices in Active Markets (Level 1) | U.S. treasury bills
Fair Value Measurements
Short-term investments:	11,015,000	0
Quoted Prices in Active Markets (Level 1) | Corporate notes
Fair Value Measurements
Short-term investments:	0
Long-term investments:	0
Significant Other Observable Inputs (Level 2)
Fair Value Measurements
Total assets	34,958,000	62,026,000
Significant Other Observable Inputs (Level 2) | Money market funds
Fair Value Measurements
Cash equivalents:	0	0
Significant Other Observable Inputs (Level 2) | Commercial paper
Fair Value Measurements
Cash equivalents:	850,000
Short-term investments:	4,228,000
Significant Other Observable Inputs (Level 2) | US Treasury Bill Securities [Member]
Fair Value Measurements
Short-term investments:	0
Long-term investments:		4,590,000
Significant Other Observable Inputs (Level 2) | U.S. government agency notes
Fair Value Measurements
Cash equivalents:		4,385,000
Short-term investments:	13,550,000	11,769,000
Significant Other Observable Inputs (Level 2) | U.S. treasury bills
Fair Value Measurements
Short-term investments:	0	41,282,000
Significant Other Observable Inputs (Level 2) | Corporate notes
Fair Value Measurements
Short-term investments:	15,278,000
Long-term investments:	1,052,000
Unobservable Inputs (Level 3)
Fair Value Measurements
Total assets	0	0
Unobservable Inputs (Level 3) | Money market funds
Fair Value Measurements
Cash equivalents:	0	0
Unobservable Inputs (Level 3) | Commercial paper
Fair Value Measurements
Cash equivalents:	0
Short-term investments:	0
Unobservable Inputs (Level 3) | US Treasury Bill Securities [Member]
Fair Value Measurements
Short-term investments:	0
Long-term investments:		0
Unobservable Inputs (Level 3) | U.S. government agency notes
Fair Value Measurements
Cash equivalents:		0
Short-term investments:	0	0
Unobservable Inputs (Level 3) | U.S. treasury bills
Fair Value Measurements
Short-term investments:	0	$ 0
Unobservable Inputs (Level 3) | Corporate notes
Fair Value Measurements
Short-term investments:	0
Long-term investments:	$ 0

Investments (Details)

Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 51,151	$ 57,691
Gross Unrealized Gains	3	23
Gross Unrealized Losses	(34)	(73)
Fair Value	51,120	57,641
Mature in less than one year, amortized cost	50,096
Mature in less than one year, fair value	50,068
Mature in one year or more, amortized cost	1,055
Mature in one year or more, fair value	1,052
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		41,282
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		11,769
U.S. treasury bonds and notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		25
Gross Unrealized Gains		9
Gross Unrealized Losses		(34)
Fair Value		0
Short-term investments:
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	50,096	53,094
Gross Unrealized Gains	3	23
Gross Unrealized Losses	(31)	(66)
Fair Value	50,068	53,051
Short-term investments: | U.S. treasury bills
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,996
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Fair Value	5,997
Short-term investments: | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,228
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	4,228
Short-term investments: | U.S. government agency notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	13,552
Gross Unrealized Gains	1
Gross Unrealized Losses	(3)
Fair Value	13,550
Short-term investments: | U.S. treasury bonds and notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	11,015
Gross Unrealized Gains	1
Gross Unrealized Losses	(1)
Fair Value	11,015
Short-term investments: | Corporate notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,305
Gross Unrealized Gains	0
Gross Unrealized Losses	(27)
Fair Value	15,278
Long-term investments: | 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		$ 4,590
Long-term investments: | Corporate notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,055
Gross Unrealized Gains	0
Gross Unrealized Losses	(3)
Fair Value	$ 1,052

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,761	$ 1,448
Less accumulated depreciation and amortization	(320)	(204)
Property and equipment, net	2,441	1,244
Depreciation and amortization expense	155	146	$ 58
Computer and lab equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	565	437
Furniture & fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	41	38
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	82	78
Construction-in-process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,073	$ 895

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued consulting	$ 106	$ 83
Accrued research and development costs	1,390	345
Accrued other	124	128
Deferred rent	59	53
Accrued liabilities	1,679	609
Less current portion	(1,650)	(569)
Long-term liability (deferred rent)	$ 29	$ 40

Stockholders' Equity (Details)

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands	Dec. 19, 2016USD ($)	Jan. 31, 2015USD ($)	Apr. 30, 2014USD ($)$ / sharesshares	Dec. 31, 2016USD ($)vote$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				10,000,000
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.0001
Preferred stock, shares outstanding (in shares)				0
Number of common shares authorized (in shares)				100,000,000	100,000,000
Common stock, par value (USD per share) | $ / shares				$ 0.0001	$ 0.0001
Stock-based compensation expense | $				$ 3,627	$ 4,157	$ 4,422
Exercise of common stock options (in shares)				39,501	58,126	56,112
Net proceeds from initial public offering | $			$ 58,065	$ 0	$ 0	$ 58,065
Exercise of stock options and purchase of ESPP shares | $				$ 23	$ 105	$ 121
Common stock, shares outstanding (in shares)				19,916,290
Maximum dollar amount of equity and debt securities offered | $		$ 150,000
Maximum aggregate offering price of common stock sold under agreement | $	$ 30,000
Common Stock
Class of Stock [Line Items]
Number of voting rights | vote				1
Restricted stock issued (in shares)						4,000
Share price (USD per share) | $ / shares			$ 18
Exercise of common stock options (in shares)				40,000	58,000	56,000
Number of shares issued during period (in shares)			3,450,000			3,450,000
Payments of underwriting commissions and offering expenses | $			$ 4,035		$ 4,035
Common stock issued under ESPP (in shares)				40,429	53,752
Proceeds from ESPP | $				$ 139	$ 238
Common Stock | Consultants | Restricted Common Stock
Class of Stock [Line Items]
Restricted stock issued (in shares)						3,750
Stock-based compensation expense | $						$ 61
Common Stock | Employee | Stock options:
Class of Stock [Line Items]
Exercise of common stock options (in shares)				39,501	58,126	56,112
Exercise of stock options and purchase of ESPP shares | $				$ 23	$ 105	$ 121
Common Stock | Employee | Stock options: | Minimum
Class of Stock [Line Items]
Stock exercise price (USD per share) | $ / shares				$ 0.32	$ 0.32	$ 0.32
Common Stock | Employee | Stock options: | Maximum
Class of Stock [Line Items]
Stock exercise price (USD per share) | $ / shares				$ 1.37	$ 3.83	$ 15.41
FBR Capital Markets & Co.
Class of Stock [Line Items]
Commission percentage of gross proceeds	3.00%

Stock-Based Awards and Benefi40

Stock-Based Awards and Benefit Plan - Narrative (Details) - USD ($)	Jan. 01, 2015	May 31, 2016	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 04, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)				3,105,819
Number of options outstanding (in shares)			2,329,415	3,568,329	3,116,185	2,329,415	1,375,914
Number of shares available for grant (in shares)			1,571,298	2,927,650	726,402	1,571,298	2,579,661
Common stock reserved for future issuance (in shares)				105,819
Aggregate intrinsic value of stock options exercised				$ 117,000	$ 266,000	$ 774,000
Exercise of stock options and purchase of ESPP shares				$ 23,000	$ 105,000	$ 121,000
Grants in period, weighted average grant date fair value (USD per share)				$ 2.45	$ 5.03	$ 12.09
Unrecognized stock-based compensation expense				$ 5,179,455
Stock options:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognition period (in years)				1 year 11 months 1 day
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted (in shares)				0	0	0
Number of unvested shares of restricted common stock (in shares)				0
2012 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)								4,000,000
2012 Equity Incentive Plan | Stock options:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (in shares)				3,495,979
2016 Equity Incentive Plan | Stock options:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period (in years)		10 years
Shares reserved for future issuance (in shares)		3,000,000
Number of options outstanding (in shares)				72,350
Percent of purchase price of common stock		100.00%
Ownership percentage by noncontrolling Owners		10.00%
Purchase price of common stock if ownership percentage surpasses threshold, percent		110.00%
Number of shares available for grant (in shares)				2,927,650
2016 Equity Incentive Plan | Minimum | Stock options:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)		1 year
2016 Equity Incentive Plan | Maximum | Stock options:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)		4 years
2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)				105,819
2014 Employee Stock Purchase Plan | Employee stock purchase plan:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)			200,000			200,000
Percent of purchase price of common stock				85.00%
Offering period (in months)			6 months
Initial offering period (in months)	5 months
Maximum number of shares per employee (in shares)			2,000
Maximum value of shares per employee			$ 25,000
Weighted average grant date fair value (USD per share)				$ 1.42
Accrued employee benefits				$ 17,000
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued under ESPP (in shares)				40,429	53,752
Common Stock | 2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock issued under ESPP (in shares)				94,181

Stock-Based Awards and Benefi41

Stock-Based Awards and Benefit Plan - Reserved Shares (Details)	Dec. 31, 2016shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	3,105,819
2014 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	105,819

Stock-Based Awards and Benefi42

Stock-Based Awards and Benefit Plan - Stock Option Plan Activity Summary (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Shares
Number of shares available for grant, beginning balance (in shares)	726,402	1,571,298	2,579,661
Number of shares issuable under options, beginning balance (in shares)	3,116,185	2,329,415	1,375,914
Granted (in shares)	(847,683)	(922,083)	(1,127,113)
Exercised (in shares)	(39,501)	(58,126)	(56,112)
Forfeited restricted stock (in shares)	312,220	72,083	118,750
Forfeited options (in shares)	(312,220)	(72,083)	(117,500)
Expired (in shares)	(43,818)	(5,104)
Number of shares available for grant, ending balance (in shares)	2,927,650	726,402	1,571,298
Number of shares issuable under options, ending balance (in shares)	3,568,329	3,116,185	2,329,415
Weighted Average Exercise Price
Granted (USD per share)	$ 3.48	$ 6.54	$ 16.23
Exercised (USD per share)	0.57	1.81	2.17
Forfeited - restricted stock and options (USD per share)			19.57
Expired (USD per share)	14.52	19.96
Forfeited - stock options (USD per share)	7.06	12.48
Outstanding (USD per share)	$ 6.36	$ 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)	7 years 6 months	8 years 2 months 12 days
Aggregate Intrinsic Value	$ 4,353	$ 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)	3,568,329
Options vested and expected to vest, weighted average exercise price (USD per share)	$ 6.36
Options vested and expected to vest, weighted average remaining contractual term (in years)	7 years 6 months
Options vested and expected to vest, aggregate intrinsic value	$ 4,353
Options exercisable, shares issuable under options (in shares)	2,298,322
Options exercisable, weighted average exercise price (USD per share)	$ 6.50
Options exercisable, weighted average remaining contractual term (in years)	7 years
Options exercisable, aggregate intrinsic value	$ 3,684
2012 Equity Incentive Plan
Shares
2012 Plan terminated (in shares)	(307,107)
2016 Equity Incentive Plan
Shares
2016 Plan authorized (in shares)	3,000,000

Stock-Based Awards and Benefi43

Stock-Based Awards and Benefit Plan - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	May 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	3,105,819
Stock-based compensation expense	$ 3,627	$ 4,157	$ 4,422
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,463	1,857	1,453
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,164	$ 2,300	$ 2,969
Stock Options | 2016 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)				3,000,000

Stock-Based Awards and Benefi44

Stock-Based Awards and Benefit Plan - Valuation Assumptions (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock options:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average risk-free interest rate	1.61%	1.51%	1.70%
Weighted average expected term (in years)	6 years 3 months 18 days	6 years 1 month 6 days	6 years 4 months 24 days
Weighted average expected volatility	83.40%	94.80%	91.30%
Weighted average expected dividend yield	0.00%	0.00%	0.00%
Employee stock purchase plan:
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average risk-free interest rate	0.50%	0.08%	0.00%
Weighted average expected term (in years)	6 months	6 months	0 years
Weighted average expected volatility	84.40%	80.70%	0.00%
Weighted average expected dividend yield	0.00%	0.00%	0.00%

Commitments and Contingencies45

Commitments and Contingencies (Details) $ in Thousands	1 Months Ended	6 Months Ended	12 Months Ended
	Oct. 31, 2016ft²	Jun. 30, 2016equipment_lease	Dec. 31, 2016USD ($)equipment_lease	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Feb. 28, 2017ft²	Feb. 14, 2017USD ($)ft²	Feb. 29, 2016ft²	Nov. 30, 2015ft²	Aug. 31, 2015ft²	Jan. 31, 2015ft²	Apr. 30, 2014ft²
Property Subject to or Available for Operating Lease [Line Items]
Number of equipment leases | equipment_lease		3
Rent expense			$ 522	$ 339	$ 162
Number of operating leases for equipment | equipment_lease			3
Lease Payments
2,017			$ 670
2,018			523
2,019			513
2,020			448
2,021			459
Thereafter			194
Total			$ 2,807
Property Subject to Operating Lease | Laboratory space
Property Subject to or Available for Operating Lease [Line Items]
Area of real estate property (in sqft) | ft²												2,145
Additional area of real estate property (in sqft) | ft²	2,326							3,599	123	131	2,431
Total area of real estate property | ft²	10,755
Extension term (in years)	5 years
Property Subject to Operating Lease | Office Space [Member]
Property Subject to or Available for Operating Lease [Line Items]
Area of real estate property (in sqft) | ft²										3,126		6,900
Subsequent Event | Property Subject to Operating Lease | Laboratory space
Property Subject to or Available for Operating Lease [Line Items]
Area of real estate property (in sqft) | ft²							11,476
Additional area of real estate property (in sqft) | ft²						721	721
Lease Payments
Total							$ 142

Restructuring Plan (Details)

Restructuring Plan (Details) $ in Thousands	Jan. 11, 2016position	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Restructuring and Related Activities [Abstract]
Number of positions eliminated	18
Percentage of workforce reduced	31.00%
Entity number of employees	39
Restructuring costs | $		$ 0	$ 0	$ 0	$ 655	$ 0	$ 0	$ 0	$ 0	$ 655	$ 0	$ 0

Income Taxes - Reconciliation S

Income Taxes - Reconciliation Statutory Federal Income Tax to Effective Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income tax expense (benefit) at statutory federal rate	$ (7,651)	$ (9,226)	$ (9,227)
State income tax, net of federal benefit	(1,389)	(1,678)	(1,663)
Permanent items	38	58	14
Research credits	(970)	(1,379)	(807)
Stock-based compensation	(29)	0	0
ASC 740-10	388	552	323
Change in valuation allowance	9,602	11,924	11,388
Other	11	(251)	(28)
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%	6.20%	6.10%
Permanent items	(0.20%)	(0.20%)	(0.10%)
Research credits	4.30%	5.10%	3.00%
Stock-based compensation	0.10%	0.00%	0.00%
ASC 740-10	(1.70%)	(2.00%)	(1.20%)
Change in valuation allowance	(42.60%)	(43.90%)	(41.90%)
Other	(0.10%)	0.80%	0.10%
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, 2016	Dec. 31, 2015
Deferred tax assets:
Net operating loss carryforwards	$ 27,093	$ 19,173
Research & development credits	2,173	1,591
Accrued expenses	720	766
Amortization and depreciation	2,738	(38)
Stock-based compensation	2,296	3,643
Other	14	2
Deferred tax assets, gross	35,034	25,137
Valuation Allowance	(35,034)	(25,137)
Net current deferred tax assets	$ 0	$ 0

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	$ 35,034,000	$ 25,137,000
Unrecognized tax benefits that would impact the effective tax rate	1,422,000
Income tax examination, penalties and interest accrued	0	0
Income tax examination, penalties and interest expense	$ 0	0	$ 0
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers		67,305,000
Federal | Research tax credit carryover
Operating Loss Carryforwards [Line Items]
Tax credit carryovers		2,215,000
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryovers		67,202,000
State | Research tax credit carryover
Operating Loss Carryforwards [Line Items]
Tax credit carryovers		$ 2,031,000

Income Taxes - Rollforward of C

Income Taxes - Rollforward of Changes in Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 1,234	$ 473
Additions based on tax positions related to the current year	464	650
Additions for tax positions of prior years	0	111
Balance at end of year	$ 1,698	$ 1,234

Net Loss Per Share (Details)

Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator:
Net loss attributable to common stockholders	$ (5,809)	$ (5,683)	$ (4,947)	$ (6,060)	$ (6,420)	$ (7,095)	$ (6,883)	$ (6,732)	$ (22,499)	$ (27,130)	$ (27,139)
Denominator:
Weighted-average number of common shares outstanding, basic and diluted (in shares)	19,900,000	19,891,000	19,865,000	19,836,000	19,816,000	19,792,000	19,756,000	19,726,000	19,873,000	19,773,000	18,782,000
Net loss per common share attributable to common stockholders, basic and diluted (USD per share)	$ (0.29)	$ (0.29)	$ (0.25)	$ (0.31)	$ (0.32)	$ (0.36)	$ (0.35)	$ (0.34)	$ (1.13)	$ (1.37)	$ (1.44)
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from EPS computation (in shares)									3,568,329	3,116,185	2,329,415

Employee Savings Plan (Details)

Employee Savings Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
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	$ 101	$ 164
Maximum
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match	3.00%

Selected Quarterly Financial 53

Selected Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating costs and expenses
Research and development	$ 3,509	$ 3,754	$ 3,161	$ 3,437	$ 4,579	$ 5,033	$ 4,991	$ 4,809	$ 13,861	$ 19,412	$ 18,694
General and administrative	2,401	2,022	1,865	2,020	1,881	2,095	1,921	1,953	8,308	7,850	8,539
Restructuring costs	0	0	0	655	0	0	0	0	655	0	0
Total operating expenses	5,910	5,776	5,026	6,112	6,460	7,128	6,912	6,762	22,824	27,262	27,233
Loss from operations	(5,910)	(5,776)	(5,026)	(6,112)	(6,460)	(7,128)	(6,912)	(6,762)	(22,824)	(27,262)	(27,233)
Interest and other income, net	101	93	79	52	40	33	29	30	325	132	94
Net loss	$ (5,809)	$ (5,683)	$ (4,947)	$ (6,060)	$ (6,420)	$ (7,095)	$ (6,883)	$ (6,732)	$ (22,499)	$ (27,130)	$ (27,139)
Net loss per share, basic and diluted (USD per share)	$ (0.29)	$ (0.29)	$ (0.25)	$ (0.31)	$ (0.32)	$ (0.36)	$ (0.35)	$ (0.34)	$ (1.13)	$ (1.37)	$ (1.44)
Weighted-average number of common shares outstanding, basic and diluted (in shares)	19,900	19,891	19,865	19,836	19,816	19,792	19,756	19,726	19,873	19,773	18,782

Subsequent Events (Details)

Subsequent Events (Details) $ in Thousands	Dec. 19, 2016USD ($)	Feb. 28, 2017USD ($)ft²	Feb. 28, 2017ft²shares	Feb. 14, 2017USD ($)ft²	Dec. 31, 2016USD ($)	Oct. 31, 2016ft²	Feb. 29, 2016ft²	Nov. 30, 2015ft²	Aug. 31, 2015ft²	Jan. 31, 2015ft²	Apr. 30, 2014ft²
Subsequent Event [Line Items]
Maximum aggregate offering price of common stock sold under agreement | $	$ 30,000
Total expected rent payments | $					$ 2,807
Operating Lease | Laboratory space
Subsequent Event [Line Items]
Additional area of real estate property (in sqft) | ft²						2,326	3,599	123	131	2,431
Area of real estate property (in sqft) | ft²											2,145
Subsequent Event
Subsequent Event [Line Items]
Net proceeds after deducting commissions and other related expenses | $		$ 11,465
Subsequent Event | Operating Lease | Laboratory space
Subsequent Event [Line Items]
Additional area of real estate property (in sqft) | ft²		721	721	721
Area of real estate property (in sqft) | ft²				11,476
Total expected rent payments | $				$ 142
FBR Capital Markets & Co.
Subsequent Event [Line Items]
Commission percentage of gross proceeds	3.00%
FBR Capital Markets & Co. | Subsequent Event
Subsequent Event [Line Items]
Number of shares issued in transaction (in shares) | shares			1,895,428