Cymabay Therapeutics (CBAY) 10-Q 9 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 31, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Trading Symbol	CBAY
Entity Registrant Name	CYMABAY THERAPEUTICS, INC.
Entity Central Index Key	1,042,074
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		23,447,003

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 12,411	$ 7,706
Marketable securities	16,705	33,774
Accrued interest receivable	19	186
Prepaid expenses	1,029	1,128
Total current assets	30,164	42,794
Property and equipment, net	90	64
Other assets	221	221
Total assets	30,475	43,079
Current liabilities:
Accounts payable	1,272	1,008
Accrued liabilities	2,897	3,336
Warrant liability	1,259	1,220
Facility loan	2,041	509
Accrued interest payable	73	73
Total current liabilities	7,542	6,146
Facility loan, less current portion	7,496	8,799
Other liabilities	16	19
Total liabilities	15,054	14,964
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.0001 par value: 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value: 100,000,000 shares authorized; 23,447,003 and 23,447,003 shares issued and outstanding as of June 30, 2016 and December 31, 2015, respectively	2	2
Additional paid-in capital	425,552	424,422
Accumulated other comprehensive loss	(5)	(21)
Accumulated deficit	(410,128)	(396,288)
Total stockholders' equity	15,421	28,115
Total liabilities and stockholders' equity	$ 30,475	$ 43,079

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	23,447,003	23,447,003
Common stock, shares outstanding	23,447,003	23,447,003

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating expenses:
Research and development	$ 4,131	$ 4,260	$ 8,559	$ 8,447
General and administrative	2,215	2,285	4,676	4,874
Total operating expenses	6,346	6,545	13,235	13,321
Loss from operations	(6,346)	(6,545)	(13,235)	(13,321)
Other income (expense):
Interest income	48	26	101	53
Interest expense	(336)	(165)	(668)	(319)
Other (expense) income, net	(358)	5,327	(38)	9,902
Net loss	(6,992)	(1,357)	(13,840)	(3,685)
Net loss	(6,992)	(1,357)	(13,840)	(3,685)
Other comprehensive (loss) income:
Unrealized (loss) gain on marketable securities, net of tax	(4)	(6)	16	1
Other comprehensive (loss) income	(4)	(6)	16	1
Comprehensive loss	$ (6,996)	$ (1,363)	$ (13,824)	$ (3,684)
Basic net loss per common share	$ (0.30)	$ (0.09)	$ (0.59)	$ (0.24)
Diluted net loss per common share	$ (0.30)	$ (0.09)	$ (0.59)	$ (0.88)
Weighted average common shares outstanding used to calculate basic net loss per common share	23,447,003	15,258,363	23,447,003	15,179,404
Weighted average common shares outstanding used to calculate diluted net loss per common share	23,447,003	15,258,363	23,447,003	15,427,832

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net loss	$ (13,840)	$ (3,685)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	11	11
Stock based compensation expense	1,130	1,312
Amortization of premium on marketable securities	133	228
Non-cash interest associated with debt discount accretion	229	86
Change in fair value of warrant liability	39	(9,902)
Changes in assets and liabilities:
Contract receivables		194
Accrued interest receivable	167	53
Prepaid expenses	99	995
Other assets		(213)
Accounts payable	264	(364)
Accrued liabilities	(439)	(224)
Accrued interest payable		38
Other liabilities	(3)	3
Net cash used in operating activities	(12,210)	(11,468)
Investing activities
Purchases of property and equipment	(37)
Purchases of marketable securities	(17,704)	(13,375)
Proceeds from maturities of marketable securities	34,656	21,028
Net cash provided by investing activities	16,915	7,653
Financing activities
Proceeds from issuance of common stock and warrants, net of issuance costs		4,263
Proceeds from issuance of common stock upon warrant exercises		426
Repayment of loan principal		(758)
Net cash provided by financing activities		3,931
Net increase in cash and cash equivalents	4,705	116
Cash and cash equivalents at beginning of period	7,706	11,586
Cash and cash equivalents at end of period	$ 12,411	$ 11,702

Organization and Description of

Organization and Description of Business	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and Description of Business CymaBay Therapeutics, Inc. (the “Company” or “CymaBay”) is a biopharmaceutical company focused on developing therapies to treat diseases with high unmet medical need, including serious rare and orphan disorders. The Company’s two key clinical development candidates are MBX-8025 and arhalofenate. MBX-8025 is currently being developed for the treatment of various orphan lipid and liver diseases. Arhalofenate is being developed for the treatment of gout. The Company was incorporated in Delaware in October 1988 as Transtech Corporation. The Company’s headquarters and operations are located in Newark, California and it operates in one segment. Liquidity The Company has incurred net operating losses and negative cash flows from operations since its inception. During the six months ended June 30, 2016, the Company incurred a net loss of $13.8 million and used $12.2 million of cash in operations. At June 30, 2016, the Company had an accumulated deficit of $410.1 million. CymaBay expects to incur increased research and development expenses as it continues to study its product candidates in clinical trials. To date, none of the Company’s product candidates have been approved for marketing and sale, and the Company has not recorded any product sales. As a result, management expects operating losses to continue in future years. The Company’s ability to achieve profitability is dependent primarily on its ability to successfully develop, acquire or in-license additional product candidates, continue clinical trials for product candidates currently in clinical development, obtain regulatory approvals, and support commercialization activities for partnered product candidates. Products developed by the Company will require approval of the U.S. Food and Drug Administration (“FDA”) or a foreign regulatory authority prior to commercial sale. The regulatory approval process is expensive, time-consuming, and uncertain, and any denial or delay of approval could have a material adverse effect on the Company. Even if approved, the Company’s products may not achieve market acceptance and will face competition from both generic and branded pharmaceutical products. As of June 30, 2016, the Company’s cash, cash equivalents and marketable securities totaled $29.1 million. These funds are expected to satisfy the Company’s liquidity requirements through at least the second quarter of 2017. The Company expects to incur substantial expenditures in the future for the development and potential commercialization of its product candidates. Because of this, the Company expects its future liquidity and capital resource needs will be impacted by numerous factors, including but not limited to, the timing of initiation of planned clinical trials, including additional phase 2 trials to study the therapeutic benefits of MBX-8025 on patients with certain orphan diseases, including primary biliary cholangitis (PBC) and homozygous familial hypercholesterolemia (HoFH), as well as a phase 3 clinical trial to study the therapeutic benefits of arhalofenate on patients with gout. The Company will therefore continue to require additional financing to develop its products and fund future operating losses and will seek funds through equity financings, debt, collaborative or other arrangements with corporate sources, or through other sources of financing. It is unclear if or when any such financing transactions will occur, on satisfactory terms or at all. The Company’s failure to raise capital as and when needed could have a negative impact on its financial condition and its ability to pursue its business strategies. If adequate funds are not available, the Company may be required to reduce development activities or to close its business, which could have an adverse impact on its ability to achieve its business objectives.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying interim condensed financial statements are unaudited. These unaudited interim financial statements have been prepared in accordance U.S. GAAP (“GAAP”) and following the requirements of the United States Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. In management’s opinion, the unaudited interim condensed financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position and its results of operations and comprehensive loss and its cash flows for the periods presented. These statements do not include all disclosures required by GAAP and should be read in conjunction with the Company’s financial statements and accompanying notes for the fiscal year ended December 31, 2015, which is contained in the Company’s Annual Report on Form 10-K as filed with the SEC on March 29, 2016. The results for the three and six months ended June 30, 2016, are not necessarily indicative of results to be expected for the year or for any other period. Use of Estimates The condensed financial statements have been prepared in accordance with GAAP, which requires management to make estimates and assumptions that affect the amounts and disclosures reported in the condensed financial statements and accompanying notes. Management bases its estimates on historical experience and on assumptions believed to be reasonable under the circumstances. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Actual results could differ materially from those estimates. The Company believes significant judgment is involved in estimating stock-based compensation, accrued clinical expenses, and equity instrument valuations. Fair Value of Financial Instruments The Company’s financial instruments during the periods reported consist of cash and cash equivalents, marketable securities, accrued interest receivable, prepaid expenses, accounts payable, accrued interest payable, accrued expenses, the facility loan, and warrant liabilities. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment. The carrying amounts of financial instruments such as cash and cash equivalents, accrued interest receivable, prepaid expenses, accounts payable, accrued expenses, and accrued interest payable approximate the related fair values due to the short maturities of these instruments. Based on prevailing borrowing rates available to the Company for loans with similar terms, the Company believes the fair value of the Facility Loan, considering level 2 inputs, approximates its carrying value. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Assets and liabilities that are measured at fair value are reported using a three-level fair value hierarchy that prioritizes the inputs used to measure fair value. This hierarchy maximizes the use of observable inputs and maximizes the use of unobservable inputs and is as follows: Level 1—Inputs which include quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2—Inputs other than quoted prices in active markets that are observable for the asset or liability, either directly or indirectly. Level 3—Inputs that are significant to the fair value measurement and are unobservable (i.e. supported by little market activity), which requires the reporting entity to develop its own valuation techniques and assumptions. As of June 30, 2016 (In thousands) Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 11,384 $ — $ — $ 11,384 Commercial paper — 899 — 899 Short-term investments: Commercial paper — 7,969 — 7,969 Corporate debt and asset backed securities — 8,736 — 8,736 Total assets measured at fair value $ 11,384 $ 17,604 $ — $ 28,988 Warrant liability $ — $ — $ 1,259 $ 1,259 Total liabilities measured at fair value $ — $ — $ 1,259 $ 1,259 As of December 31, 2015 (In thousands) Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 6,942 $ — $ — $ 6,942 Short-term investments: Commercial paper — 5,992 — 5,992 Government debt securities — 1,507 — 1,507 Corporate debt and asset backed securities — 26,275 — 26,275 Total assets measured at fair value $ 6,942 $ 33,774 $ — $ 40,716 Warrant liability $ — $ — $ 1,220 $ 1,220 Total liabilities measured at fair value $ — $ — $ 1,220 $ 1,220 The Company estimates the fair value of its corporate debt, government debt, money market funds, commercial paper, and asset backed securities by taking into consideration valuations obtained from third-party pricing services. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads; benchmark securities; prepayment/default projections based on historical data; and other observable inputs. There were no transfers between Level 1 and Level 2 during the periods presented. The Company holds a Level 3 liability associated with common stock warrants that were issued in connection with the Company’s financings completed in September and October 2013, January 2014, and August 2015. The warrants are classified as liabilities and recorded at fair value using a binomial lattice option-pricing model, the inputs for which include the exercise price of the warrants, market price of the underlying common shares, expected term, volatility, the risk-free rate, and the expected changes in stock price that follow announcements of the Company’s clinical trial results and other strategic initiatives. Changes to any of the inputs to the valuation model used by the Company can have a significant impact to the estimated fair value of the warrants. The following table sets forth an activity summary which includes the changes in the fair value of the Company’s Level 3 financial instruments (in thousands): For the Six Months Ended June 30, 2016 2015 Balance, beginning of period $ 1,220 $ 13,596 Issuance of financial instrument — — Change in fair value 39 (9,902 ) Settlement of financial instrument — (1,513 ) Balance, end of period $ 1,259 $ 2,181 Cash, Cash Equivalents, and Marketable Securities The Company considers all highly liquid investments with a remaining maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist primarily of deposits with commercial banks in checking, interest-bearing, and demand money market accounts. The Company invests excess cash in marketable securities with high credit ratings. These securities consist primarily of corporate debt and asset-backed securities and are classified as “available-for-sale.” Management may liquidate any of these investments in order to meet the Company’s liquidity needs in the next year. Accordingly, any investments with contractual maturities greater than one year from the balance sheet date are classified as short-term in the condensed balance sheets. Realized gains and losses from the sale of marketable securities, if any, are calculated using the specific identification method. Realized gains and losses and declines in value judged to be other-than-temporary are included in interest income or expense in the statements of operations. Unrealized holding gains and losses are reported in accumulated other comprehensive loss, in the balance sheets. To date, the Company has not recorded any impairment charges on its marketable securities related to other-than-temporary declines in market value. In determining whether a decline in market value is other-than-temporary, various factors are considered, including the cause, duration of time and severity of the impairment, any adverse changes in the investees’ financial condition, and the Company’s intent and ability to hold the security for a period of time sufficient to allow for an anticipated recovery in market value. Marketable securities in the condensed balance sheets, all of which are classified as available-for-sale, consisted of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of June 30, 2016: Corporate debt securities $ 12,797 $ — $ (4 ) $ 12,793 Asset-backed securities 3,913 — (1 ) 3,912 $ 16,710 $ — $ (5 ) $ 16,705 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of December 31, 2015: Government debt securities $ 1,509 $ — $ (2 ) $ 1,507 Corporate debt securities 27,663 — $ (17 ) 27,646 Asset-backed securities 4,623 — (2 ) 4,621 $ 33,795 $ — $ (21 ) $ 33,774 At June 30, 2016, and December 31, 2015, the remaining contractual maturities of the Company’s government and corporate debt securities was less than one year and asset backed securities was between two and five years. Realized gains and losses were immaterial for all periods presented. None of these investments has been in a continuous unrealized loss position for more than 12 months as of June 30, 2016, or December 31, 2015. Restricted Cash The Company is required to maintain compensating cash balances with financial institutions that provide the Company with its corporate credit cards. As of June 30, 2016, and December 31, 2015, cash restricted under these arrangements was $170,000. This amount is presented in other assets on the accompanying condensed balance sheets. Concentration of Credit Risk Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to a concentration of credit risk to the extent of the fair value recorded in the balance sheet. The Company invests cash that is not required for immediate operating needs primarily in highly liquid instruments that bear minimal risk. The Company has established guidelines relating to the quality, diversification, and maturities of securities to enable the Company to manage its credit risk. The counterparties to the agreements relating to the Company’s investments consist of financial institutions of high credit standing. Common Stock Warrant Liability Warrants issued to common stock holders and lenders by the Company in conjunction with financings from 2013 through 2015 are classified as liabilities in the accompanying condensed balance sheets, as the terms for redemption of the underlying security are outside the Company’s control. The warrants are recorded at fair value and are re-measured at each financial reporting period until the warrants are exercised or expire and immediately before exercise, with any changes in fair value being recognized as a component of other income (expense), net in the accompanying condensed statements of operations and comprehensive loss. Research and Development Expenses Research and development expenses consist of costs incurred in identifying, developing, and testing product candidates. These expenses consist primarily of costs for research and development personnel (including related stock-based compensation); contract research organizations and other third parties that assist in managing, monitoring, and analyzing clinical trials; investigator and site fees; laboratory services; consultants; contract manufacturing services; non-clinical studies, including materials; and allocated expenses, such as depreciation of assets, and facilities and information technology that support research and development activities. Research and development costs are expensed as incurred, including expenses that may or may not be reimbursed under research and development funding arrangements. The expenses related to clinical trials are based upon estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and clinical research organizations (CROs) that conduct and manage clinical trials on behalf of the Company. Expenses related to clinical trials are accrued based upon the level of activity incurred under each contract as indicated by such factors as progress made against specified milestones or targets in each period, patient enrollment levels, and other trial activities as reported by CROs. Accordingly, the Company’s clinical trial accrual is dependent upon the timely and accurate reporting of expenses by clinical research organizations and other third-party vendors. Payments made to third parties under these clinical trial arrangements in advance of the receipt of the related services are recorded as prepaid assets, depending on the terms of the agreement, until the services are rendered. Stock-Based Compensation Employee and director stock-based compensation is measured at the grant date, based on the fair-value of the awards, and the portion that is ultimately expected to vest is recognized as an expense over the related vesting periods, net of estimated forfeitures. The Company calculates the fair-value of option grants and incentive awards using the Black-Scholes model and recognizes expense using the straight-line attribution method. Equity awards granted to non-employees are valued using the Black-Scholes option pricing model to determine the fair value of such instruments. The fair value of equity awards granted to non-employees are re-measured throughout the related vesting period and amortized to expense over that period. Net Loss Per Common Share Basic net loss per share of common stock is calculated as the weighted average number of shares of common stock outstanding equivalents during the period. Diluted net loss per share of common stock is calculated as the weighted average number of shares of common stock outstanding adjusted to include the assumed exercises of stock options and warrants, if dilutive. The calculation of diluted loss per share also requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the warrants and the presumed exercise of such securities are dilutive to earnings (loss) per share for the period, adjustments to net income or net loss used in the calculation are required to remove the change in fair value of the warrants for the period. Likewise, adjustments to the denominator are required to reflect the related dilutive shares. In all periods presented, the Company’s outstanding stock options and incentive awards were excluded from the calculation of net loss per share because the effect would be antidilutive. The Company’s computation of net loss per share is as follows (in thousands, except share and per share amounts): Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Numerator: Net loss allocated to common stock-basic $ (6,992 ) $ (1,357 ) $ (13,840 ) $ (3,685 ) Adjustments for revaluation of warrants — — — (9,902 ) Net loss allocated to common stock-diluted $ (6,992 ) $ (1,357 ) $ (13,840 ) $ (13,587 ) Denominator: Weighted average number of common stock shares outstanding — basic 23,447,003 15,258,363 23,447,003 15,179,404 Dilutive Securities: Common stock warrants — — — 248,428 Weighted average number of common stock shares outstanding — diluted 23,447,003 15,258,363 23,447,003 15,427,832 Net loss per share—basic: $ (0.30 ) $ (0.09 ) $ (0.59 ) $ (0.24 ) Net loss per share—diluted: $ (0.30 ) $ (0.09 ) $ (0.59 ) $ (0.88 ) The following table shows the total outstanding common stock equivalents considered anti-dilutive and therefore excluded from the computation of diluted net loss per share (in thousands). Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Warrants for common stock 1,667 1,553 1,667 — Common stock options 2,415 1,794 2,415 1,794 Incentive awards 243 245 243 245 4,325 3,592 4,325 2,039 Recent Accounting Pronouncements Accounting Standards Update 2014-15 In August 2014, the FASB issued guidance codified in ASC 205, Presentation of Financial Statements — Going Concern. Accounting Standards Update 2014-15 requires an entity’s management to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern and if those conditions exist, to make the required disclosures. Early adoption will be permitted. The standard is effective for annual periods ending after December 15, 2016, and for annual and interim periods thereafter. The Company does not expect that the adoption of this standard will have a significant impact on its condensed financial statements. Accounting Standards Update 2015-03 In April 2015, the FASB issued ASU No. 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, which requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the corresponding debt liability rather than as an asset. The Company adopted this ASU with retrospective application in the first quarter of 2016. As the Company does not have any debt issuance costs recorded as assets, the adoption of this standard did not have any impact on its condensed financial statements. Accounting Standards Update 2016-02 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The ASU requires management to recognize lease assets and lease liabilities by lessees for most leases. The ASU is effective for the annual periods beginning after December 15, 2018 and interim periods therein on a modified retrospective basis. The Company is currently evaluating the impact this guidance will have on its condensed financial statements. Accounting Standards Update 2016-09 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 financial statements. The ASU will be effective for the Company for the annual periods beginning after December 15, 2016 and interim periods within those annual periods on a modified retrospective basis. The Company is currently evaluating the impact this guidance will have on its condensed financial statements. Accounting Standards Update 2016-13 In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326), which introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. It also modifies the impairment model for available–for-sale debt securities and provides for a simplified accounting model for purchased financial assets with deterioration since their origination. The ASU is effective for the annual periods beginning after December 15, 2019 including interim periods within those annual periods. The Company is currently evaluating the impact this guidance will have on its condensed financial statements.

Certain Balance Sheet Items

Certain Balance Sheet Items	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Certain Balance Sheet Items	3. Certain Balance Sheet Items Accrued liabilities consist of the following (in thousands): June 30, December 31, 2016 2015 (unaudited) Accrued compensation $ 1,055 $ 1,010 Accrued pre-clinical and clinical trial expenses 1,510 2,015 Accrued professional fees 266 283 Other accruals 66 28 Total accrued liabilities $ 2,897 $ 3,336

Common Stock Warrants

Common Stock Warrants	6 Months Ended
	Jun. 30, 2016
Text Block [Abstract]
Common Stock Warrants	4. Common Stock Warrants During the three and six months ended June 30, 2015, the Company issued an aggregate of 9,703 and 132,295 shares of common stock, respectively, to stockholders upon the exercise of warrants exercisable for shares of the Company’s common stock. The 132,295 shares of common stock were issued pursuant to both cash and net exercise provisions as provided in the warrants. Specifically, 74,136 shares of the Company’s common stock were issued in exchange for $0.4 million in cash and 58,159 shares of the Company’s common stock were issued in exchange for shares of its common stock in accordance with net exercise provisions. For each warrant exercised, the Company determined the warrant’s exercise date fair value and reclassified the fair value of such settled warrants from the warrant liability to additional paid-in capital, a component of stockholder’s equity. The aggregate amount of these fair value reclassifications totaled $0.2 million and $1.5 million during the three and six months ended June 30, 2015, respectively. No warrants were issued or exercised for the three and six months ended June 30, 2016.

Collaboration and License Agree

Collaboration and License Agreements	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	5. Collaboration and License Agreements Janssen Pharmaceutical NV and Janssen Pharmaceuticals, Inc. In June 2006, the Company entered into an exclusive worldwide, royalty-bearing license to MBX-8025 and certain other PPAR d d d d d d d d In June 2010, the Company entered into two development and license agreements with Janssen Pharmaceuticals, Inc. (Janssen), a subsidiary of Johnson and Johnson, to further develop and discover undisclosed metabolic disease target agonists for the treatment of T2DM and other disorders and received a one-time nonrefundable technology access fee related to the agreements. The Company received a termination notice from Janssen, effectively ending these development and licensing agreements in early April 2015. In December 2015, the Company exercised an option pursuant to the terms of one of the original agreements to continue work to research, develop and commercialize compounds with activity against an undisclosed metabolic disease target. Janssen granted the Company an exclusive, worldwide license (with rights to sublicense) under the Janssen know-how and patents to research, develop, make, have made, use, offer for sale and sell such compounds. The Company has full control and responsibility over the research, development and registration of any products developed and/or discovered from the metabolic disease target and is required to use diligent efforts to conduct all such activities. Dia Tex, Inc. In June 1998, the Company entered into a license agreement with DiaTex, Inc. (DiaTex) relating to products containing halofenate, its enantiomers, derivatives, and analogs (the licensed products). The license agreement provides that DiaTex and the Company are joint owners of all of the patents and patent applications covering the licensed products and methods of producing or using such compounds, as well as certain other know-how (the covered IP). As part of the license agreement, the Company received an exclusive worldwide license, including as to DiaTex, to use the covered IP to develop and commercialize the licensed products. The Company also retained the right to sub-license the covered IP. The license agreement contains a $2,000 per month license fee as well as a requirement to make additional payments for development achievements and royalty payments on any sales of licensed products. DiaTex is entitled to up to $0.8 million for the future development of arhalofenate, as well as royalty payments on any sales of products containing arhalofenate. No development payments were made in the three and six months ended June 30, 2016 and 2015 and no royalties have been paid to date.

Facility Loans

Facility Loans	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
Facility Loans	6. Facility Loans 2013 Term Loan Facility On September 30, 2013, the Company entered into a facility loan agreement with Silicon Valley Bank and Oxford Finance LLC (referred to herein as the lenders) for a total loan amount of $10.0 million of which the first tranche of $5.0 million was drawn as part of the Company’s September 2013 financing, referred to herein as the 2013 Term Loan Facility. The loan had a fixed interest rate of 8.75% payable as interest only for twelve months and a thirty-six month loan amortization period thereafter, with a final interest payment of $0.3 million at the end of the loan period. The second tranche of $5.0 million became available to the Company upon its February 24, 2015, announcement of the achievement of positive Phase 2b data for the Company’s product candidate arhalofenate and remained available to the Company until June 30, 2015. On June 30, 2015, the second tranche portion of the loan facility expired unused by the Company. At the time the first $5.0 million tranche of the facility loan was drawn down, the Company issued warrants exercisable for a total of 121,739 shares of the Company’s common stock to the lenders at an exercise price of $5.00 per share. Upon issuance, the fair value of a warrant liability was recorded and is being revalued at each balance sheet date until the warrants are exercised or expire. 2015 Term Loan Facility On August 7, 2015, the Company entered into a Loan and Security Agreement pursuant to which it refinanced its existing 2013 Term Loan Facility with Oxford Finance LLC and Silicon Valley Bank, for an aggregate amount of up to $15.0 million, referred to herein as the 2015 Term Loan Facility. The first $10.0 million tranche of this new loan facility was made available to the Company immediately upon the closing and was used in part to retire all $4.1 million of the Company’s existing debt outstanding under the 2013 Term Loan Facility, and to settle accrued interest and closing costs with the lenders. The remaining $5.0 million, referred to as the second tranche, was made available to the Company until March 31, 2016, for draw down upon the announcement of a qualified out-license or co-development arrangement for arhalofenate, the Company’s gout therapy drug candidate, which includes an upfront payment of not less than $35.0 million (the second draw milestone). Because the present value of the future cash flows under the modified loan terms did not exceed the present value of the future cash flows under the previous loan terms by more than 10%, the Company treated this refinancing as a modification. The remaining debt discount costs will be amortized over the remaining term of the Loan and Security Agreement using the effective interest rate method. As of March 31, 2016, the $5.0 million second tranche expired unused as the second draw milestone was not achieved. The first loan tranche bears interest at 8.77%, a rate which was determined on the advance date as being the greater of (i) 8.75% and (ii) the sum of 8.47% and the 90 day U.S. LIBOR rate reported in the Wall Street Journal three business days prior to the funding date of the first tranche. Under the first tranche, the Company is required to make 12 monthly interest only payments after the funding date followed by a repayment schedule equal to 36 equal monthly payments of interest and principal. Upon maturity, the remaining balance of the first tranche and a final payment equal to 6.50% of the original principal amount advanced of the applicable tranche are payable. At the closing, the Company also agreed to pay a facility fee of 1.00% of the 2015 Term Loan Facility commitment. In addition, the Company issued warrants exercisable for a total of 114,436 shares of its common stock to the lenders at an exercise price of $2.84 per share, and with a term of ten years. Upon issuance, the fair value of a warrant liability of $0.3 million was recorded in the accompanying balance sheet and is being revalued at each balance sheet date until the warrants are exercised or expire. The 2015 Term Loan Facility contains customary representations and warranties and customary affirmative and negative covenants applicable to the Company, and also includes defined customary events of default. As of June 30, 2016, the Company was in compliance with the term loan covenants and there were no identified events of default.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies The Company leases 8,894 square feet of office space in Newark, California pursuant to a lease which commenced January 16, 2014 and expires on December 31, 2018. Rent expense was $0.1 million for each of the three months ended June 30, 2016 and 2015, and $0.2 million for each of the six months ended June 30, 2016 and 2015. Future minimum lease payments are as follows (in thousands): Lease Payments Year ending December 31: 2016 (from July to December) $ 108 2017 222 2018 228 Total future minimum payments $ 558 Indemnification In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnification, including indemnification associated with product liability or infringement of intellectual property rights. The Company’s exposure under these agreements is unknown because it involves future claims that may be made against the Company that may be, but have not yet been, made. To date, the Company has not paid any claims or been required to defend any action related to these indemnification obligations, and no amounts have been accrued in the accompanying consolidated balance sheets related to these indemnification obligations. The Company has agreed to indemnify its executive officers and directors for losses and costs incurred in connection with certain events or occurrences, including advancing money to cover certain costs, subject to certain limitations. The maximum potential amount of future payments the Company could be required to make under this indemnification is unlimited; however, the Company maintains insurance policies that may limit its exposure and may enable it to recover a portion of any future amounts paid. Assuming the applicability of coverage, the willingness of the insurer to assume coverage, and subject to certain retention, loss limits, and other policy provisions, the Company believes the fair value of these indemnification obligations is not material. Accordingly, the Company has not recognized any liabilities relating to these obligations as of June 30, 2016, and December 31, 2015. No assurances can be given that the covering insurers will not attempt to dispute the validity, applicability, or amount of coverage without expensive litigation against these insurers, in which case the Company may incur substantial liabilities as a result of these indemnification obligations.

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity The Company is authorized to issue 10,000,000 shares of preferred stock with a par value of $0.0001 per share as of June 30, 2016. The Company is authorized to issue 100,000,000 shares of common stock with a par value of $0.0001 per share as of June 30, 2016. As of June 30, 2016 and December 31, 2015, the Company had reserved shares of authorized but unissued common stock as follows: June 30, December 31, 2016 2015 (unaudited) Common stock warrants 1,667,398 1,667,398 Equity incentive plans 3,456,771 2,284,421 Total reserved shares of common stock 5,124,169 3,951,819

Stock Plans and Stock-Based Com

Stock Plans and Stock-Based Compensation	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Plans and Stock-Based Compensation	9. Stock Plans and Stock-Based Compensation Stock Plans On January 1, 2016, the share reserve of the Company’s 2013 Equity Incentive Plan (“2013 Plan”), automatically increased by 1,172,350 shares. As of June 30, 2016, there were 798,104 shares available for issuance under the 2013 Plan. Stock-Based Compensation Expense Stock-based compensation expense recorded, net of estimated forfeitures, was as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 (unaudited) (unaudited) Research and development $ 223 $ 202 $ 445 $ 415 General and administrative 347 378 685 897 Total $ 570 $ 580 $ 1,130 $ 1,312

Related-Party Transactions

Related-Party Transactions	6 Months Ended
	Jun. 30, 2016
Related Party Transactions [Abstract]
Related-Party Transactions	10. Related-Party Transactions The Company paid a former member of its Board of Directors, who is also a member of its Scientific and Clinical Advisory Boards, a total of $60,000 in the year ended December 31, 2015 and $30,000 for the six months ended June 30, 2016, in monthly cash retainers. The Company also granted 9,000 options to purchase shares of common stock to this individual in his capacity as a member of its Scientific Advisory Board for the six months ended June 30, 2016.

Subsequent Event

Subsequent Event	6 Months Ended
	Jun. 30, 2016
Subsequent Events [Abstract]
Subsequent Event	11. Subsequent Event In July 2016, we granted 350,000 stock options to employees, of which 327,000 included vesting conditions associated with achievement of certain clinical development and capital raising milestones through 2016.

Organization and Description 17

Organization and Description of Business (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Liquidity	Liquidity The Company has incurred net operating losses and negative cash flows from operations since its inception. During the six months ended June 30, 2016, the Company incurred a net loss of $13.8 million and used $12.2 million of cash in operations. At June 30, 2016, the Company had an accumulated deficit of $410.1 million. CymaBay expects to incur increased research and development expenses as it continues to study its product candidates in clinical trials. To date, none of the Company’s product candidates have been approved for marketing and sale, and the Company has not recorded any product sales. As a result, management expects operating losses to continue in future years. The Company’s ability to achieve profitability is dependent primarily on its ability to successfully develop, acquire or in-license additional product candidates, continue clinical trials for product candidates currently in clinical development, obtain regulatory approvals, and support commercialization activities for partnered product candidates. Products developed by the Company will require approval of the U.S. Food and Drug Administration (“FDA”) or a foreign regulatory authority prior to commercial sale. The regulatory approval process is expensive, time-consuming, and uncertain, and any denial or delay of approval could have a material adverse effect on the Company. Even if approved, the Company’s products may not achieve market acceptance and will face competition from both generic and branded pharmaceutical products. As of June 30, 2016, the Company’s cash, cash equivalents and marketable securities totaled $29.1 million. These funds are expected to satisfy the Company’s liquidity requirements through at least the second quarter of 2017. The Company expects to incur substantial expenditures in the future for the development and potential commercialization of its product candidates. Because of this, the Company expects its future liquidity and capital resource needs will be impacted by numerous factors, including but not limited to, the timing of initiation of planned clinical trials, including additional phase 2 trials to study the therapeutic benefits of MBX-8025 on patients with certain orphan diseases, including primary biliary cholangitis (PBC) and homozygous familial hypercholesterolemia (HoFH), as well as a phase 3 clinical trial to study the therapeutic benefits of arhalofenate on patients with gout. The Company will therefore continue to require additional financing to develop its products and fund future operating losses and will seek funds through equity financings, debt, collaborative or other arrangements with corporate sources, or through other sources of financing. It is unclear if or when any such financing transactions will occur, on satisfactory terms or at all. The Company’s failure to raise capital as and when needed could have a negative impact on its financial condition and its ability to pursue its business strategies. If adequate funds are not available, the Company may be required to reduce development activities or to close its business, which could have an adverse impact on its ability to achieve its business objectives.
Basis of Presentation	Basis of Presentation The accompanying interim condensed financial statements are unaudited. These unaudited interim financial statements have been prepared in accordance U.S. GAAP (“GAAP”) and following the requirements of the United States Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP can be condensed or omitted. In management’s opinion, the unaudited interim condensed financial statements have been prepared on the same basis as the audited financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position and its results of operations and comprehensive loss and its cash flows for the periods presented. These statements do not include all disclosures required by GAAP and should be read in conjunction with the Company’s financial statements and accompanying notes for the fiscal year ended December 31, 2015, which is contained in the Company’s Annual Report on Form 10-K as filed with the SEC on March 29, 2016. The results for the three and six months ended June 30, 2016, are not necessarily indicative of results to be expected for the year or for any other period.
Use of Estimates	Use of Estimates The condensed financial statements have been prepared in accordance with GAAP, which requires management to make estimates and assumptions that affect the amounts and disclosures reported in the condensed financial statements and accompanying notes. Management bases its estimates on historical experience and on assumptions believed to be reasonable under the circumstances. The estimation process often may yield a range of potentially reasonable estimates of the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Actual results could differ materially from those estimates. The Company believes significant judgment is involved in estimating stock-based compensation, accrued clinical expenses, and equity instrument valuations.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments during the periods reported consist of cash and cash equivalents, marketable securities, accrued interest receivable, prepaid expenses, accounts payable, accrued interest payable, accrued expenses, the facility loan, and warrant liabilities. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment. The carrying amounts of financial instruments such as cash and cash equivalents, accrued interest receivable, prepaid expenses, accounts payable, accrued expenses, and accrued interest payable approximate the related fair values due to the short maturities of these instruments. Based on prevailing borrowing rates available to the Company for loans with similar terms, the Company believes the fair value of the Facility Loan, considering level 2 inputs, approximates its carrying value. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Assets and liabilities that are measured at fair value are reported using a three-level fair value hierarchy that prioritizes the inputs used to measure fair value. This hierarchy maximizes the use of observable inputs and maximizes the use of unobservable inputs and is as follows: Level 1—Inputs which include quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2—Inputs other than quoted prices in active markets that are observable for the asset or liability, either directly or indirectly. Level 3—Inputs that are significant to the fair value measurement and are unobservable (i.e. supported by little market activity), which requires the reporting entity to develop its own valuation techniques and assumptions. As of June 30, 2016 (In thousands) Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 11,384 $ — $ — $ 11,384 Commercial paper — 899 — 899 Short-term investments: Commercial paper — 7,969 — 7,969 Corporate debt and asset backed securities — 8,736 — 8,736 Total assets measured at fair value $ 11,384 $ 17,604 $ — $ 28,988 Warrant liability $ — $ — $ 1,259 $ 1,259 Total liabilities measured at fair value $ — $ — $ 1,259 $ 1,259 As of December 31, 2015 (In thousands) Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 6,942 $ — $ — $ 6,942 Short-term investments: Commercial paper — 5,992 — 5,992 Government debt securities — 1,507 — 1,507 Corporate debt and asset backed securities — 26,275 — 26,275 Total assets measured at fair value $ 6,942 $ 33,774 $ — $ 40,716 Warrant liability $ — $ — $ 1,220 $ 1,220 Total liabilities measured at fair value $ — $ — $ 1,220 $ 1,220 The Company estimates the fair value of its corporate debt, government debt, money market funds, commercial paper, and asset backed securities by taking into consideration valuations obtained from third-party pricing services. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, issuer credit spreads; benchmark securities; prepayment/default projections based on historical data; and other observable inputs. There were no transfers between Level 1 and Level 2 during the periods presented. The Company holds a Level 3 liability associated with common stock warrants that were issued in connection with the Company’s financings completed in September and October 2013, January 2014, and August 2015. The warrants are classified as liabilities and recorded at fair value using a binomial lattice option-pricing model, the inputs for which include the exercise price of the warrants, market price of the underlying common shares, expected term, volatility, the risk-free rate, and the expected changes in stock price that follow announcements of the Company’s clinical trial results and other strategic initiatives. Changes to any of the inputs to the valuation model used by the Company can have a significant impact to the estimated fair value of the warrants. The following table sets forth an activity summary which includes the changes in the fair value of the Company’s Level 3 financial instruments (in thousands): For the Six Months Ended June 30, 2016 2015 Balance, beginning of period $ 1,220 $ 13,596 Issuance of financial instrument — — Change in fair value 39 (9,902 ) Settlement of financial instrument — (1,513 ) Balance, end of period $ 1,259 $ 2,181
Cash, Cash Equivalents, and Marketable Securities	Cash, Cash Equivalents, and Marketable Securities The Company considers all highly liquid investments with a remaining maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist primarily of deposits with commercial banks in checking, interest-bearing, and demand money market accounts. The Company invests excess cash in marketable securities with high credit ratings. These securities consist primarily of corporate debt and asset-backed securities and are classified as “available-for-sale.” Management may liquidate any of these investments in order to meet the Company’s liquidity needs in the next year. Accordingly, any investments with contractual maturities greater than one year from the balance sheet date are classified as short-term in the condensed balance sheets. Realized gains and losses from the sale of marketable securities, if any, are calculated using the specific identification method. Realized gains and losses and declines in value judged to be other-than-temporary are included in interest income or expense in the statements of operations. Unrealized holding gains and losses are reported in accumulated other comprehensive loss, in the balance sheets. To date, the Company has not recorded any impairment charges on its marketable securities related to other-than-temporary declines in market value. In determining whether a decline in market value is other-than-temporary, various factors are considered, including the cause, duration of time and severity of the impairment, any adverse changes in the investees’ financial condition, and the Company’s intent and ability to hold the security for a period of time sufficient to allow for an anticipated recovery in market value. Marketable securities in the condensed balance sheets, all of which are classified as available-for-sale, consisted of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of June 30, 2016: Corporate debt securities $ 12,797 $ — $ (4 ) $ 12,793 Asset-backed securities 3,913 — (1 ) 3,912 $ 16,710 $ — $ (5 ) $ 16,705 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of December 31, 2015: Government debt securities $ 1,509 $ — $ (2 ) $ 1,507 Corporate debt securities 27,663 — $ (17 ) 27,646 Asset-backed securities 4,623 — (2 ) 4,621 $ 33,795 $ — $ (21 ) $ 33,774 At June 30, 2016, and December 31, 2015, the remaining contractual maturities of the Company’s government and corporate debt securities was less than one year and asset backed securities was between two and five years. Realized gains and losses were immaterial for all periods presented. None of these investments has been in a continuous unrealized loss position for more than 12 months as of June 30, 2016, or December 31, 2015.
Restricted Cash	Restricted Cash The Company is required to maintain compensating cash balances with financial institutions that provide the Company with its corporate credit cards. As of June 30, 2016, and December 31, 2015, cash restricted under these arrangements was $170,000. This amount is presented in other assets on the accompanying condensed balance sheets.
Concentration of Credit Risk	Concentration of Credit Risk Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to a concentration of credit risk to the extent of the fair value recorded in the balance sheet. The Company invests cash that is not required for immediate operating needs primarily in highly liquid instruments that bear minimal risk. The Company has established guidelines relating to the quality, diversification, and maturities of securities to enable the Company to manage its credit risk. The counterparties to the agreements relating to the Company’s investments consist of financial institutions of high credit standing.
Common Stock Warrant Liability	Common Stock Warrant Liability Warrants issued to common stock holders and lenders by the Company in conjunction with financings from 2013 through 2015 are classified as liabilities in the accompanying condensed balance sheets, as the terms for redemption of the underlying security are outside the Company’s control. The warrants are recorded at fair value and are re-measured at each financial reporting period until the warrants are exercised or expire and immediately before exercise, with any changes in fair value being recognized as a component of other income (expense), net in the accompanying condensed statements of operations and comprehensive loss.
Research and Development Expenses	Research and Development Expenses Research and development expenses consist of costs incurred in identifying, developing, and testing product candidates. These expenses consist primarily of costs for research and development personnel (including related stock-based compensation); contract research organizations and other third parties that assist in managing, monitoring, and analyzing clinical trials; investigator and site fees; laboratory services; consultants; contract manufacturing services; non-clinical studies, including materials; and allocated expenses, such as depreciation of assets, and facilities and information technology that support research and development activities. Research and development costs are expensed as incurred, including expenses that may or may not be reimbursed under research and development funding arrangements. The expenses related to clinical trials are based upon estimates of the services received and efforts expended pursuant to contracts with multiple research institutions and clinical research organizations (CROs) that conduct and manage clinical trials on behalf of the Company. Expenses related to clinical trials are accrued based upon the level of activity incurred under each contract as indicated by such factors as progress made against specified milestones or targets in each period, patient enrollment levels, and other trial activities as reported by CROs. Accordingly, the Company’s clinical trial accrual is dependent upon the timely and accurate reporting of expenses by clinical research organizations and other third-party vendors. Payments made to third parties under these clinical trial arrangements in advance of the receipt of the related services are recorded as prepaid assets, depending on the terms of the agreement, until the services are rendered.
Stock-Based Compensation	Stock-Based Compensation Employee and director stock-based compensation is measured at the grant date, based on the fair-value of the awards, and the portion that is ultimately expected to vest is recognized as an expense over the related vesting periods, net of estimated forfeitures. The Company calculates the fair-value of option grants and incentive awards using the Black-Scholes model and recognizes expense using the straight-line attribution method. Equity awards granted to non-employees are valued using the Black-Scholes option pricing model to determine the fair value of such instruments. The fair value of equity awards granted to non-employees are re-measured throughout the related vesting period and amortized to expense over that period.
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per share of common stock is calculated as the weighted average number of shares of common stock outstanding equivalents during the period. Diluted net loss per share of common stock is calculated as the weighted average number of shares of common stock outstanding adjusted to include the assumed exercises of stock options and warrants, if dilutive. The calculation of diluted loss per share also requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the warrants and the presumed exercise of such securities are dilutive to earnings (loss) per share for the period, adjustments to net income or net loss used in the calculation are required to remove the change in fair value of the warrants for the period. Likewise, adjustments to the denominator are required to reflect the related dilutive shares. In all periods presented, the Company’s outstanding stock options and incentive awards were excluded from the calculation of net loss per share because the effect would be antidilutive. The Company’s computation of net loss per share is as follows (in thousands, except share and per share amounts): Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Numerator: Net loss allocated to common stock-basic $ (6,992 ) $ (1,357 ) $ (13,840 ) $ (3,685 ) Adjustments for revaluation of warrants — — — (9,902 ) Net loss allocated to common stock-diluted $ (6,992 ) $ (1,357 ) $ (13,840 ) $ (13,587 ) Denominator: Weighted average number of common stock shares outstanding — basic 23,447,003 15,258,363 23,447,003 15,179,404 Dilutive Securities: Common stock warrants — — — 248,428 Weighted average number of common stock shares outstanding — diluted 23,447,003 15,258,363 23,447,003 15,427,832 Net loss per share—basic: $ (0.30 ) $ (0.09 ) $ (0.59 ) $ (0.24 ) Net loss per share—diluted: $ (0.30 ) $ (0.09 ) $ (0.59 ) $ (0.88 ) The following table shows the total outstanding common stock equivalents considered anti-dilutive and therefore excluded from the computation of diluted net loss per share (in thousands). Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Warrants for common stock 1,667 1,553 1,667 — Common stock options 2,415 1,794 2,415 1,794 Incentive awards 243 245 243 245 4,325 3,592 4,325 2,039
Recent Accounting Pronouncements	Recent Accounting Pronouncements Accounting Standards Update 2014-15 In August 2014, the FASB issued guidance codified in ASC 205, Presentation of Financial Statements — Going Concern. Accounting Standards Update 2014-15 requires an entity’s management to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern and if those conditions exist, to make the required disclosures. Early adoption will be permitted. The standard is effective for annual periods ending after December 15, 2016, and for annual and interim periods thereafter. The Company does not expect that the adoption of this standard will have a significant impact on its condensed financial statements. Accounting Standards Update 2015-03 In April 2015, the FASB issued ASU No. 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, which requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the corresponding debt liability rather than as an asset. The Company adopted this ASU with retrospective application in the first quarter of 2016. As the Company does not have any debt issuance costs recorded as assets, the adoption of this standard did not have any impact on its condensed financial statements. Accounting Standards Update 2016-02 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The ASU requires management to recognize lease assets and lease liabilities by lessees for most leases. The ASU is effective for the annual periods beginning after December 15, 2018 and interim periods therein on a modified retrospective basis. The Company is currently evaluating the impact this guidance will have on its condensed financial statements. Accounting Standards Update 2016-09 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 financial statements. The ASU will be effective for the Company for the annual periods beginning after December 15, 2016 and interim periods within those annual periods on a modified retrospective basis. The Company is currently evaluating the impact this guidance will have on its condensed financial statements. Accounting Standards Update 2016-13 In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments – Credit Losses (Topic 326), which introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. It also modifies the impairment model for available–for-sale debt securities and provides for a simplified accounting model for purchased financial assets with deterioration since their origination. The ASU is effective for the annual periods beginning after December 15, 2019 including interim periods within those annual periods. The Company is currently evaluating the impact this guidance will have on its condensed financial statements.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis	As of June 30, 2016 (In thousands) Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 11,384 $ — $ — $ 11,384 Commercial paper — 899 — 899 Short-term investments: Commercial paper — 7,969 — 7,969 Corporate debt and asset backed securities — 8,736 — 8,736 Total assets measured at fair value $ 11,384 $ 17,604 $ — $ 28,988 Warrant liability $ — $ — $ 1,259 $ 1,259 Total liabilities measured at fair value $ — $ — $ 1,259 $ 1,259 As of December 31, 2015 (In thousands) Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 6,942 $ — $ — $ 6,942 Short-term investments: Commercial paper — 5,992 — 5,992 Government debt securities — 1,507 — 1,507 Corporate debt and asset backed securities — 26,275 — 26,275 Total assets measured at fair value $ 6,942 $ 33,774 $ — $ 40,716 Warrant liability $ — $ — $ 1,220 $ 1,220 Total liabilities measured at fair value $ — $ — $ 1,220 $ 1,220
Schedule of Changes in Fair Value of Financial Instruments	The following table sets forth an activity summary which includes the changes in the fair value of the Company’s Level 3 financial instruments (in thousands): For the Six Months Ended June 30, 2016 2015 Balance, beginning of period $ 1,220 $ 13,596 Issuance of financial instrument — — Change in fair value 39 (9,902 ) Settlement of financial instrument — (1,513 ) Balance, end of period $ 1,259 $ 2,181
Schedule of Marketable Securities Classified as Available-for-Sale	Marketable securities in the condensed balance sheets, all of which are classified as available-for-sale, consisted of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of June 30, 2016: Corporate debt securities $ 12,797 $ — $ (4 ) $ 12,793 Asset-backed securities 3,913 — (1 ) 3,912 $ 16,710 $ — $ (5 ) $ 16,705 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of December 31, 2015: Government debt securities $ 1,509 $ — $ (2 ) $ 1,507 Corporate debt securities 27,663 — $ (17 ) 27,646 Asset-backed securities 4,623 — (2 ) 4,621 $ 33,795 $ — $ (21 ) $ 33,774
Computation of Net Loss per Share	The Company’s computation of net loss per share is as follows (in thousands, except share and per share amounts): Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Numerator: Net loss allocated to common stock-basic $ (6,992 ) $ (1,357 ) $ (13,840 ) $ (3,685 ) Adjustments for revaluation of warrants — — — (9,902 ) Net loss allocated to common stock-diluted $ (6,992 ) $ (1,357 ) $ (13,840 ) $ (13,587 ) Denominator: Weighted average number of common stock shares outstanding — basic 23,447,003 15,258,363 23,447,003 15,179,404 Dilutive Securities: Common stock warrants — — — 248,428 Weighted average number of common stock shares outstanding — diluted 23,447,003 15,258,363 23,447,003 15,427,832 Net loss per share—basic: $ (0.30 ) $ (0.09 ) $ (0.59 ) $ (0.24 ) Net loss per share—diluted: $ (0.30 ) $ (0.09 ) $ (0.59 ) $ (0.88 )
Anti-Dilutive Common Stock Equivalents Excluded from the Computation of Diluted Net Loss per Share	The following table shows the total outstanding common stock equivalents considered anti-dilutive and therefore excluded from the computation of diluted net loss per share (in thousands). Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 Warrants for common stock 1,667 1,553 1,667 — Common stock options 2,415 1,794 2,415 1,794 Incentive awards 243 245 243 245 4,325 3,592 4,325 2,039

Certain Balance Sheet Items (Ta

Certain Balance Sheet Items (Tables)	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued Liabilities	Accrued liabilities consist of the following (in thousands): June 30, December 31, 2016 2015 (unaudited) Accrued compensation $ 1,055 $ 1,010 Accrued pre-clinical and clinical trial expenses 1,510 2,015 Accrued professional fees 266 283 Other accruals 66 28 Total accrued liabilities $ 2,897 $ 3,336

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	Future minimum lease payments are as follows (in thousands): Lease Payments Year ending December 31: 2016 (from July to December) $ 108 2017 222 2018 228 Total future minimum payments $ 558

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
Reserved Shares of Authorized but Unissued Common Stock	As of June 30, 2016 and December 31, 2015, the Company had reserved shares of authorized but unissued common stock as follows: June 30, December 31, 2016 2015 (unaudited) Common stock warrants 1,667,398 1,667,398 Equity incentive plans 3,456,771 2,284,421 Total reserved shares of common stock 5,124,169 3,951,819

Stock Plans and Stock-Based C22

Stock Plans and Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock-Based Compensation Expense, Net of Estimated Forfeitures	Stock-based compensation expense recorded, net of estimated forfeitures, was as follows (in thousands): Three Months Ended Six Months Ended June 30, June 30, 2016 2015 2016 2015 (unaudited) (unaudited) Research and development $ 223 $ 202 $ 445 $ 415 General and administrative 347 378 685 897 Total $ 570 $ 580 $ 1,130 $ 1,312

Organization and Description 23

Organization and Description of Business - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net loss	$ (6,992)	$ (1,357)	$ (13,840)	$ (3,685)
Cash flows from operating activities			(12,210)	$ (11,468)
Accumulated deficit	(410,128)		(410,128)		$ (396,288)
Cash and cash equivalents and marketable securities	$ 29,100		$ 29,100

Summary of Significant Accoun24

Summary of Significant Accounting Policies - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 28,988	$ 40,716
Total liabilities measured at fair value	1,259	1,220
Warrant Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	1,259	1,220
Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	11,384	6,942
Cash Equivalents [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	899
Short-term Investments [Member] | Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		1,507
Short-term Investments [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	7,969	5,992
Short-term Investments [Member] | Corporate Debt and Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	8,736	26,275
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	11,384	6,942
Level 1 [Member] | Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	11,384	6,942
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	17,604	33,774
Level 2 [Member] | Cash Equivalents [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	899
Level 2 [Member] | Short-term Investments [Member] | Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		1,507
Level 2 [Member] | Short-term Investments [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	7,969	5,992
Level 2 [Member] | Short-term Investments [Member] | Corporate Debt and Asset Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	8,736	26,275
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	1,259	1,220
Level 3 [Member] | Warrant Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	$ 1,259	$ 1,220

Summary of Significant Accoun25

Summary of Significant Accounting Policies - Schedule of Changes in Fair Value of Financial Instruments (Detail) - Level 3 [Member] - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Instruments Classified in Shareholders' Equity Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 1,220	$ 13,596
Issuance of financial instrument	0	0
Change in fair value	39	(9,902)
Settlement of financial instrument		(1,513)
Ending Balance	$ 1,259	$ 2,181

Summary of Significant Accoun26

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Product Information [Line Items]
Cash and cash equivalents, maturity description	90 days or less
Short-term contractual maturities	1 year
Restricted cash	$ 170,000	$ 170,000
Government Debt Securities [Member] | Maximum [Member]
Product Information [Line Items]
Marketable securities contractual maturities	1 year
Corporate Debt Securities [Member] | Maximum [Member]
Product Information [Line Items]
Marketable securities contractual maturities	1 year
Debt Securities [Member]
Product Information [Line Items]
Marketable investments continuous unrealized loss position	$ 0	$ 0
Asset-backed Securities [Member] | Minimum [Member]
Product Information [Line Items]
Marketable securities contractual maturities	2 years
Asset-backed Securities [Member] | Maximum [Member]
Product Information [Line Items]
Marketable securities contractual maturities	5 years

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Schedule of Marketable Securities Classified as Available-for-Sale (Detail) - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 16,710	$ 33,795
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(5)	(21)
Estimated Fair Value	16,705	33,774
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,797	27,663
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(4)	(17)
Estimated Fair Value	12,793	27,646
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,913	4,623
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(2)
Estimated Fair Value	$ 3,912	4,621
Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		1,509
Gross Unrealized Gains		0
Gross Unrealized Losses		(2)
Estimated Fair Value		$ 1,507

Summary of Significant Accoun28

Summary of Significant Accounting Policies - Computation of Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Numerator:
Net loss allocated to common stock-basic	$ (6,992)	$ (1,357)	$ (13,840)	$ (3,685)
Adjustments for revaluation of warrants				(9,902)
Net loss allocated to common stock-diluted	$ (6,992)	$ (1,357)	$ (13,840)	$ (13,587)
Denominator:
Weighted average number of common stock shares outstanding - basic	23,447,003	15,258,363	23,447,003	15,179,404
Dilutive Securities Common stock warrants				248,428
Weighted average number of common stock shares outstanding - diluted	23,447,003	15,258,363	23,447,003	15,427,832
Net loss per share-basic:	$ (0.30)	$ (0.09)	$ (0.59)	$ (0.24)
Net loss per share-diluted:	$ (0.30)	$ (0.09)	$ (0.59)	$ (0.88)

Summary of Significant Accoun29

Summary of Significant Accounting Policies - Anti-Dilutive Common Stock Equivalents Excluded from the Computation of Diluted Net Loss per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents excluded from the computation of diluted loss per share	4,325	3,592	4,325	2,039
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents excluded from the computation of diluted loss per share	1,667	1,553	1,667
Common Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents excluded from the computation of diluted loss per share	2,415	1,794	2,415	1,794
Incentive Awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive common stock equivalents excluded from the computation of diluted loss per share	243	245	243	245

Certain Balance Sheet Items - A

Certain Balance Sheet Items - Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Accrued compensation	$ 1,055	$ 1,010
Accrued pre-clinical and clinical trial expenses	1,510	2,015
Accrued professional fees	266	283
Other accruals	66	28
Total accrued liabilities	$ 2,897	$ 3,336

Common Stock Warrants - Additio

Common Stock Warrants - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Equity [Abstract]
Issuance of common stock upon exercise of warrants	0	9,703	0	132,295
Issuance of common stock upon exercise of warrants on cash basis		74,136
Proceeds from issuance of common stock upon warrant exercises		$ 400		$ 426
Issuance of common stock in accordance with net exercise provisions		58,159
Fair value reclassification of warrant liability to additional paid-in capital		$ 200		$ 1,500

Collaboration and License Agr32

Collaboration and License Agreements - Additional Information (Detail)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 1998USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)Agreement	Jun. 30, 2015USD ($)
DiaTex, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License agreement date				Jun. 30, 1998
Monthly license fees	$ 2,000
Potential future development payments	$ 800,000
Development payment		$ 0	$ 0	$ 0	$ 0
Royalty payment		$ 0	$ 0	$ 0	$ 0
Janssen Pharmaceutical NV [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales				8.00%
Janssen Pharmaceuticals, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License agreement date				Jun. 30, 2010
Number of development and license agreements | Agreement				2

Facility Loans - Additional Inf

Facility Loans - Additional Information (Detail) - USD ($)	Aug. 07, 2015	Sep. 30, 2013	Jun. 30, 2016	Mar. 31, 2016
Debt Instrument [Line Items]
Issued warrants to purchase common stock			114,436
Exercise price of common stock			$ 2.84
Warrant term			10 years
Warrants [Member]
Debt Instrument [Line Items]
Fair value of warrant liabilities		$ 300,000
Warrants, Exercise Price of $5.00 Per Share [Member]
Debt Instrument [Line Items]
Issued warrants to purchase common stock		121,739
Exercise price of common stock		$ 5
Second Tranche [Member]
Debt Instrument [Line Items]
Facility loan, unused amount expired				$ 5,000,000
2013 Term Loan Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 10,000,000
Facility loan, interest amortization period		36 months
Facility loan, final interest payment		$ 300,000
Retiring of existing debt	$ 4,100,000
2013 Term Loan Facility [Member] | First Tranche [Member]
Debt Instrument [Line Items]
Facility loan, drawn		$ 5,000,000
Facility loan, fixed interest rate		8.75%
2013 Term Loan Facility [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Facility loan available for draw down		$ 5,000,000
2015 Term Loan Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 15,000,000
Debt instrument payment terms			Under the first tranche, the Company is required to make 12 monthly interest only payments after the funding date followed by a repayment schedule equal to 36 equal monthly payments of interest and principal.
Percentage of principal amount as final payment	6.50%
Facility fee	1.00%
2015 Term Loan Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Upfront Payment	$ 35,000,000
Present value of the future cash flows	10.00%
2015 Term Loan Facility [Member] | First Tranche [Member]
Debt Instrument [Line Items]
Facility loan, drawn	$ 10,000,000
Facility loan, fixed interest rate	8.77%
2015 Term Loan Facility [Member] | First Tranche [Member] | Minimum [Member]
Debt Instrument [Line Items]
Facility loan, fixed interest rate	8.75%
2015 Term Loan Facility [Member] | First Tranche [Member] | Wall Street Journal Prime Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Facility loan, fixed interest rate	8.47%
2015 Term Loan Facility [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Facility loan available for draw down	$ 5,000,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Nov. 08, 2013ft²	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Loss Contingencies [Line Items]
Rent expenses		$ 100,000	$ 100,000	$ 200,000	$ 200,000
Accrued in the consolidated balance sheets related to indemnification obligations		0		0
Indemnification liabilities		$ 0		$ 0		$ 0
Lease Facility [Member]
Loss Contingencies [Line Items]
Area of office space | ft²	8,894
Lease start date	Jan. 16, 2014
Lease expiration date	Dec. 31, 2018

Commitments and Contingencies35

Commitments and Contingencies - Future Minimum Lease Payments (Detail) $ in Thousands	Jun. 30, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
2016 (from July to December)	$ 108
2,017	222
2,018	228
Total future minimum payments	$ 558

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
Equity [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.0001	$ 0.0001

Stockholders' Equity - Reserved

Stockholders' Equity - Reserved Shares of Authorized but Unissued Common Stock (Detail) - shares	Jun. 30, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Total reserved shares of common stock	5,124,169	3,951,819
Common Stock Warrants [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	1,667,398	1,667,398
Equity Incentive Plans [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	3,456,771	2,284,421

Stock Plans and Stock-Based C38

Stock Plans and Stock-Based Compensation - Additional Information (Detail) - 2013 Equity Incentive Plan [Member] - shares	Jan. 01, 2016	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant		798,104
Increased in shares available for issuance	1,172,350

Stock Plans and Stock-Based C39

Stock Plans and Stock-Based Compensation - Summary of Stock-Based Compensation Expense, Net of Estimated Forfeitures (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 570	$ 580	$ 1,130	$ 1,312
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	223	202	445	415
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 347	$ 378	$ 685	$ 897

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - Former Member of Board of Directors [Member] - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Advisory fee paid to related party	$ 30,000	$ 60,000
Number of options granted to purchase shares of common stock	9,000

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - Subsequent Event [Member] - Employees [Member] - Stock Options [Member]	1 Months Ended
	Jul. 31, 2016shares
Subsequent Event [Line Items]
Number of option granted to employees	350,000
Number of stock options granted to employees that included vesting conditions	327,000