Cymabay Therapeutics (CBAY) 10-Q 11 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	CYMA
Entity Registrant Name	CymaBay Therapeutics, Inc.
Entity Central Index Key	1042074
Current Fiscal Year End Date	-19
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		15,259,003

Condensed_Balance_Sheets

Condensed Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$10,841	$11,586
Marketable securities	21,950	23,209
Contract receivables		211
Accrued interest receivable	199	136
Prepaid expenses	1,363	1,991
Other current assets	139	96
Total current assets	34,492	37,229
Property and equipment, net	80	86
Other assets	158	159
Total assets	34,730	37,474
Current liabilities:
Accounts payable	1,527	2,085
Accrued liabilities	2,998	3,388
Warrant liability	7,704	13,596
Facility loan	1,403	1,355
Accrued interest payable	32	35
Total current liabilities	13,664	20,459
Facility loan, less current portion	2,784	3,152
Other liabilities	14	13
Total liabilities	16,462	23,624
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; 15,249,300 and 14,696,108 shares issued and outstanding as of March 31, 2015 and December 31, 2014, respectively	1	1
Additional paid-in capital	401,361	394,622
Accumulated other comprehensive loss	-7	-14
Accumulated deficit	-383,087	-380,759
Total stockholders' equity	18,268	13,850
Total liabilities and stockholders' equity	$34,730	$37,474

Condensed_Balance_Sheets_Paren

Condensed Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Preferred stock, par value	$0.00	$0.00
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	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	15,249,300	14,696,108
Common stock, shares outstanding	15,249,300	14,696,108

Condensed_Statements_of_Operat

Condensed Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating expenses:
Research and development	$4,187	$2,615
General and administrative	2,589	2,500
Total operating expenses	6,776	5,115
Loss from operations	-6,776	-5,115
Other income (expense):
Interest income	27	12
Interest expense	-154	-184
Other income (expense), net	4,575	-4,775
Net loss	-2,328	-10,062
Net loss	-2,328	-10,062
Other comprehensive income:
Unrealized gain on marketable securities	7	1
Other comprehensive income	7	1
Comprehensive loss	($2,321)	($10,061)
Basic net loss per common share	($0.15)	($1.02)
Diluted net loss per common share	($0.44)	($1.02)
Weighted average common shares outstanding used to calculate basic net loss per common share	15,099,567	9,873,687
Weighted average common shares outstanding used to calculate diluted net loss per common share	15,743,167	9,873,687

Condensed_Statements_of_Cash_F

Condensed Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating activities
Net loss	($2,328)	($10,062)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	6	3
Non-employee stock-based compensation expense	28	2
Employee and director stock-based compensation expense	705	714
Amortization of premium on marketable securities	167	71
Non-cash interest associated with debt discount accretion	36	49
Change in fair value of warrant liability	-4,575	4,784
Changes in assets and liabilities:
Contract receivables	211	-58
Accrued interest receivable	-63	-22
Prepaid expenses	628	-1,512
Other assets	-42	-211
Accounts payable	-558	372
Accrued liabilities	-390	830
Accrued interest payable	15	26
Other liabilities	1	3
Net cash used in operating activities	-6,159	-5,011
Investing activities
Purchases of property and equipment		-32
Purchases of marketable securities	-6,617
Proceeds from sales and maturities of marketable securities	7,716	582
Net cash provided by investing activities	1,099	550
Financing activities
Proceeds from issuance of common stock, net of issuance costs	4,263	2,402
Proceeds from issuance of common stock upon warrant exercises	426
Repayment of loan principal	-374
Net cash provided by financing activities	4,315	2,402
Net decrease in cash and cash equivalents	-745	-2,059
Cash and cash equivalents at beginning of period	11,586	24,401
Cash and cash equivalents at end of period	10,841	22,342
Supplemental disclosure of cash flow information
Cash paid for interest	101	109
Fixed assets in accrued expenses		28
Issuance of common stock warrants		443
Issuance of common stock upon warrant exercises	1,317	55
Noncash issuance costs incurred in common stock financing		$453

Organization_and_Description_o

Organization and Description of Business	3 Months Ended
	Mar. 31, 2015
Accounting Policies [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 metabolic diseases with high unmet medical need, including serious rare and orphan disorders. The Company’s lead product candidate, arhalofenate, is being developed for the treatment of gout. The Company’s second product candidate, MBX-8025, is being considered for the treatment of certain orphan diseases. 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 three months ended March 31, 2015, the Company incurred a loss from operations of $2.3 million and used $6.2 million of cash in operations. At March 31, 2015, the Company had an accumulated deficit of $383.1 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 March 31, 2015, the Company’s cash, cash equivalents and marketable securities totaled $32.8 million. These funds, together with $5 million available for drawdown under a facility loan, will satisfy the Company’s liquidity requirements through at least the end of the first quarter of 2016. 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 phase 2 trials to study the therapeutic benefits of MBX-8025 on patients with certain orphan diseases as well as a phase 3 clinical trial to study the therapeutic benefits of arhaolfenate 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.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
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 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, 2014, which is contained in the Company’s Annual Report on Form 10-K as filed with the SEC on March 23, 2015. The results for the three months ended March 31, 2015, are not necessarily indicative of results to be expected for the year or for any other period.
	Use of Estimates
	The 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 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 liabilities, and equity and liability instrument valuations.
	Fair Value of Financial Instruments
	The Company’s financial instruments during the periods reported consist of cash and cash equivalents, contract receivables, short-term marketable securities, accounts payable, accrued expenses, 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 and therefore cannot be determined with precision.
	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—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 unobservable for the asset or liability.
	The carrying amounts of financial instruments such as cash and cash equivalents, contract receivables, accounts payable and accrued expenses approximate the related fair values due to the short-term maturities of these instruments. The carrying value of the facility loan is reflective of the fair value based on market interest rates.
		As of March 31, 2015
		(In thousands)
	Description	Level 1			Level 2			Level 3		Fair Value
	Money market funds	$	9,660		$	—		$	—	$	9,660
	Corporate debt and asset backed securities		—			21,950			—		21,950
	Total assets measured at fair value	$	9,660		$	21,950		$	—	$	31,610
	Warrant liability	$	—		$	—		$	7,704	$	7,704
	Total liabilities measured at fair value	$	—		$	—		$	7,704	$	7,704
		As of December 31, 2014
		(In thousands)
	Description	Level 1			Level 2			Level 3		Fair Value
	Money market funds	$	9,941		$	—		$	—	$	9,941
	Corporate debt and asset backed securities		—			23,209			—		23,209
	Total assets measured at fair value	$	9,941		$	23,209		$	—	$	33,150
	Warrant liability	$	—		$	—		$	13,596	$	13,596
	Total liabilities measured at fair value	$	—		$	—		$	13,596	$	13,596
	Marketable securities consist of available-for-sale securities that are reported at fair value, with the related unrealized gains and losses included in accumulated other comprehensive income (loss). The Company values cash equivalents and marketable securities using quoted market prices or alternative pricing sources and models utilizing observable market inputs and, as such, classifies cash equivalents and marketable securities within Level 1 or Level 2.
	The Company holds a Level 3 liability associated with common stock warrants that were issued in connection with the Company’s 2013 financing. The warrants are considered a liability and are valued using an option-pricing model, the inputs for which include the exercise price of the warrants, market price of the underlying common shares, expected term, volatility based on a group of the Company’s peers and the risk-free rate corresponding to the expected term of the warrants. Changes to any of the inputs to the option-pricing models 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):
		Warrant
		Liability
	Balance as of December 31, 2014	$	13,596
	Issuance of financial instrument		—
	Change in fair value		(4,575	)
	Settlement of financial instrument		(1,317	)
	Balance as of March 31, 2015	$	7,704
	The gains and losses from remeasurement of Level 3 financial liabilities are recorded through other income (expense), net on the accompanying condensed statements of operations and comprehensive loss.
	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 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 balance sheet.
	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 income (loss), in the balance sheet. 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.
	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 March 31, 2015 and December 31, 2014, cash restricted under these arrangements was $100,000. 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.
	Property and Equipment
	Property and equipment is stated at cost, less accumulated depreciation and amortization. Depreciation and amortization is calculated using the straight-line method, and the cost is amortized over the estimated useful lives of the respective assets, generally three to seven years. Leasehold improvements are amortized over the shorter of the useful lives or the non-cancelable term of the related lease. Maintenance and repair costs are charged as expense in the statements of operations and comprehensive income (loss) as incurred.
	Impairment of Long-Lived Assets
	The Company reviews long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. An impairment loss is recognized if the estimated undiscounted future cash flow expected to result from the use and eventual disposition of an asset is less than the carrying amount. While the Company’s current and historical operating losses and cash flows are indicators of impairment, the Company believes the future cash flows to be received support the carrying value of its long-lived assets. Accordingly, the Company has not recognized any impairment losses as of March 31, 2015 and December 31, 2014.
	Deferred Rent
	The Company records its costs under facility operating lease agreements as rent expense. Rent expense is recognized on a straight-line basis over the non-cancelable term of the operating lease. The difference between the actual amounts paid and amounts recorded as rent expense is recorded to deferred rent in the balance sheet.
	Common Stock Warrant Liability
	Warrants issued to common stock holders and lenders by the Company in conjunction with the 2013 financing were classified as liabilities in the accompanying condensed balance sheets, as the terms for redemption of the underlying security were outside the Company’s control. The warrants were recorded at fair value using either the Black-Scholes option pricing model, probability weighted expected return model or a binomial model, depending on the characteristics of the warrants. The fair value of these warrants is re-measured at each financial reporting period 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 based measurements of the stock 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 based measurements of options using the Black-Scholes valuation model and recognizes expense using the straight-line attribution method.
	Equity awards granted to non-employees are accounted for using the Black-Scholes valuation model to determine the fair value of such instruments. The fair value of equity awards granted to non-employees are re-measured over the related vesting period and amortized to expense as earned.
	Income Taxes
	The Company utilizes the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between the financial reporting and the tax bases of assets and liabilities and are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that all or part of a deferred tax asset will not be realized.
	The accounting guidance for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination based on the technical merits of the position. The Company records interest related to income taxes, if any, as interest, and any penalties would be recorded as other expense in the statements of comprehensive income (loss). There was no interest or penalties related to income taxes recorded during the three months ended March 31, 2015 and 2014.
	Comprehensive Loss
Comprehensive loss includes net loss and net unrealized gains and losses on marketable securities, which are presented in a single continuous statement. Accumulated other comprehensive income (loss) is disclosed in the condensed balance sheets, and is stated net of related tax effects, if any.
Net Loss Per Common Share
Basic net loss per share of common stock is based on 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.
The Company’s computation of loss per share is as follows (in thousands, except share and per share amounts):
	Three Months Ended
	March 31,
	2015			2014
Numerator:
Net loss allocated to common stock-basic	$	(2,328	)	$	(10,062	)
Adjustments for revaluation of warrants		(4,575	)		—
Net loss allocated to common stock-diluted		(6,903	)		(10,062	)
Denominator:
Weighted average number of common stock shares outstanding—basic		15,099,567			9,873,687
Dilutive Securities
Common stock warrants		643,600			—
Weighted average number of common stock shares outstanding—diluted		15,743,167			9,873,687
Net loss per share-basic:	$	(0.15	)	$	(1.02	)
Net loss per share—diluted	$	(0.44	)	$	(1.02	)
The following table shows the total outstanding securities considered anti-dilutive and therefore excluded from the computation of diluted net loss per share.
	Three Months
	Ended March 31,
	2015			2014
	(unaudited)
Warrants for common stock		—			1,848
Common stock options		1,707			907
Incentive awards		247			—
		1,954			2,755

Certain_Balance_Sheet_Items

Certain Balance Sheet Items	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Certain Balance Sheet Items	3. Certain Balance Sheet Items
	Property and equipment consists of the following (in thousands):
		March 31,			December 31,
		2015			2014
		(unaudited)
	Office and computer equipment	$	176		$	176
	Purchased software		46			46
	Furniture and fixtures		33			33
	Leasehold improvements		66			66
	Total		321			321
	Less accumulated depreciation and amortization		(241	)		(235	)
	Property and equipment, net	$	80		$	86
	Accrued liabilities consist of the following (in thousands):
		March 31,			December 31,
		2015			2014
		(unaudited)
	Accrued compensation	$	580		$	1,504
	Accrued pre-clinical and clinical trial expenses		1,967			1,732
	Accrued professional fees		380			73
	Other accruals		71			79
	Total accrued liabilities	$	2,998		$	3,388

Common_Stock_Warrants

Common Stock Warrants	3 Months Ended
	Mar. 31, 2015
Text Block [Abstract]
Common Stock Warrants	4. Common Stock Warrants
	During the three months ended March 31, 2015, the Company issued an aggregate of 122,592 shares of common stock to stockholders upon the exercise of warrants exercisable for shares of the Company’s common stock. The 122,592 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 and 48,456 shares of the Company’s common stock were issued in exchange for cancellation of 52,793 shares its common stock. 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 $1.3 million during the three months ended March 31, 2015.
	In January 2014, in connection with the 2013 financing, the Company completed the sale of common stock for aggregate proceeds of $3.0 million and as part of this transaction, the Company issued five-year warrants to purchase 120,800 shares of common stock at an exercise price of $5.75 per share. Due to certain provisions, the Company is required to account for the warrants issued as a liability at fair value. In addition, the estimated liability related to the warrants is required to be revalued at each reporting period until the earlier of the exercise of the warrants, at which time the liability will be reclassified to stockholders’ equity, or expiration of the warrants. At issuance date, the fair value of the total warrant liability was estimated to be $0.4 million using a binomial lattice options-pricing model.

Collaboration_and_License_Agre

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	5. Collaboration and License Agreements
	In June 2006, the Company entered into an exclusive worldwide, royalty-bearing license to MBX-8025 and certain other PPARd compounds (the “PPARd Products”) with Janssen Pharmaceutical NV, with the right to grant sublicenses to third parties to make, use and sell such PPARd Products. Under the terms of the agreement, the Company has full control and responsibility over the research, development and registration of any PPARd Products and is required to use diligent efforts to conduct all such activities. Janssen has the sole responsibility for the preparation, filing, prosecution, maintenance of, and defense of the patents with respect to, the PPARd Products. Janssen has a right of first negotiation under the agreement to license a particular PPARd Product from the Company in the event that the Company elects to seek a third party corporate partner for the research, development, promotion, and/or commercialization of such PPARd Products. Under the terms of the agreement Janssen is entitled to receive up to an 8% royalty on net sales of PPARd Products. No payments were made and no royalties were received under this agreement during the three months ended March 31, 2015 and 2014.
	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 is also eligible to receive up to $228 million in contingent payments if certain development and commercial events are achieved as well as royalties on worldwide net sales of products. No such payments have been made to date. Under the terms of the agreements, Janssen has full control and responsibility over the research, development and registration of any products developed and/or discovered from the metabolic disease targets and is required to use diligent efforts to conduct all such activities. The Company received a termination notice from Johnson and Johnson, effectively ending these development and licensing agreements in early April 2015.
	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. Pursuant to the license agreement, all of the Company’s patents and patent applications related to arhalofenate, its use, and production are jointly owned with DiaTex. 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 months ended March 31, 2015 and 2014 and no royalties have been paid to date.

Facility_Loan

Facility Loan	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Facility Loan	6. Facility Loan
	On September 30, 2013, the Company entered into a facility loan agreement with Silicon Valley Bank and Oxford Finance for a total loan amount of $10.0 million of which the first tranche of $5.0 million was drawn as part of the 2013 financing. The loan has 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 (the second draw milestone) and shall remain available to the Company until June 30, 2015. Loans under the second tranche will bear interest at a rate fixed at the time of borrowing equal to the greater of (i) 8.75% per annum and (ii) the sum of the Wall Street Journal prime rate plus 4.25% per annum. The Company was also required to pay a facility fee of 1.00% on the term loan facility commitment. As of March 31, 2015, the Company had not drawn down any amount under the $5 million second tranche.
	At the time the first $5 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. As a result of this issuance, a warrant liability of $0.5 million was recorded in the accompanying condensed balance sheets and it must be revalued at each balance sheet date.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies
	The Company leased office and laboratory space in a single building in Hayward, California. The facility lease, as amended on July 15, 2010, had a term of four years and expired on April 30, 2014. On November 8, 2013, the Company entered into a new lease commencing January 16, 2014, and expiring on December 31, 2018, for 8,894 square feet of office space in Newark, California. Rent expense was $0.1 million and $0.2 million for the three months ended March 31, 2015 and 2014, respectively.
	Future minimum lease payments are as follows (in thousands):
		Lease
		Payments
	Year ending December 31:
	2015 (from April to December)		157
	2016		216
	2017		222
	2018		228
	Total future minimum payments	$	823
	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 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 March 31, 2015 and December 31, 2014. 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	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity
	The Company is authorized to issue 100,000,000 shares of common stock with a par value of $0.0001 per share as of March 31, 2015.
	As of March 31, 2015 and December 31, 2014, the Company had reserved shares of authorized but unissued common stock as follows:
		March 31,		December 31,
		2015		2014
		(unaudited)
	Common stock warrants		1,592,962		1,768,347
	Equity incentive plans		2,284,421		1,549,616
	Total reserved shares of common stock		3,877,383		3,317,963

Stock_Plans_and_StockBased_Com

Stock Plans and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2015
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, 2015, the share reserve of the Company’s 2013 Equity Incentive Plan, or 2013 Plan, automatically increased by 734,805 shares. From plan inception through March 31, 2015, the Company had granted options for an aggregate of 1,652,850 shares of the Company’s common stock under the 2013 Plan.
	Stock-Based Compensation Expense
	Employee and Director Expense
	Employee and director stock-based compensation expense recorded was as follows (in thousands):
		Three Months Ended
		March 31,
		2015		2014
		(unaudited)
	Research and development	$	186	$	146
	General and administrative		519		568
	Total	$	705	$	714
	On June 3, 2014, stockholders approved a proposal to increase the Company’s stock option plan share reserve with sufficient shares to enable the Company to share settle certain incentive awards previously issued to the Company’s employees and directors. Prior to the share reserve increase the Company could only cash settle the incentive awards and therefore these awards were required to be revalued at each reporting date and presented as liabilities on the condensed balance sheet. On June 3, 2014, the incentive awards became equity classified for accounting purposes and accordingly, the Company revalued the awards and reclassified $0.1 million from accrued liabilities to additional paid in capital.

RelatedParty_Transactions

Related-Party Transactions	3 Months Ended
	Mar. 31, 2015
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, 2014 and $15,000 for the three months ended March 31, 2015, in monthly cash retainers. The Company also issued options to purchase shares of common stock and incentive awards to this individual in his capacity as a member of its Scientific Advisory Board.

Organization_and_Description_o1

Organization and Description of Business (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Liquidity	Liquidity
	The Company has incurred net operating losses and negative cash flows from operations since its inception. During the three months ended March 31, 2015, the Company incurred a loss from operations of $2.3 million and used $6.2 million of cash in operations. At March 31, 2015, the Company had an accumulated deficit of $383.1 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 March 31, 2015, the Company’s cash, cash equivalents and marketable securities totaled $32.8 million. These funds, together with $5 million available for drawdown under a facility loan, will satisfy the Company’s liquidity requirements through at least the end of the first quarter of 2016. 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 phase 2 trials to study the therapeutic benefits of MBX-8025 on patients with certain orphan diseases as well as a phase 3 clinical trial to study the therapeutic benefits of arhaolfenate 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.
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 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, 2014, which is contained in the Company’s Annual Report on Form 10-K as filed with the SEC on March 23, 2015. The results for the three months ended March 31, 2015, are not necessarily indicative of results to be expected for the year or for any other period.
Use of Estimates	Use of Estimates
	The 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 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 liabilities, and equity and liability 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, contract receivables, short-term marketable securities, accounts payable, accrued expenses, 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 and therefore cannot be determined with precision.
	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—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 unobservable for the asset or liability.
	Marketable securities consist of available-for-sale securities that are reported at fair value, with the related unrealized gains and losses included in accumulated other comprehensive income (loss). The Company values cash equivalents and marketable securities using quoted market prices or alternative pricing sources and models utilizing observable market inputs and, as such, classifies cash equivalents and marketable securities within Level 1 or Level 2.
	The Company holds a Level 3 liability associated with common stock warrants that were issued in connection with the Company’s 2013 financing. The warrants are considered a liability and are valued using an option-pricing model, the inputs for which include the exercise price of the warrants, market price of the underlying common shares, expected term, volatility based on a group of the Company’s peers and the risk-free rate corresponding to the expected term of the warrants. Changes to any of the inputs to the option-pricing models used by the Company can have a significant impact to the estimated fair value of the warrants.
	The gains and losses from remeasurement of Level 3 financial liabilities are recorded through other income (expense), net on the accompanying condensed statements of operations and comprehensive loss.
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 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 balance sheet.
	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 income (loss), in the balance sheet. 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.
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 March 31, 2015 and December 31, 2014, cash restricted under these arrangements was $100,000. 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.
Property and Equipment	Property and Equipment
	Property and equipment is stated at cost, less accumulated depreciation and amortization. Depreciation and amortization is calculated using the straight-line method, and the cost is amortized over the estimated useful lives of the respective assets, generally three to seven years. Leasehold improvements are amortized over the shorter of the useful lives or the non-cancelable term of the related lease. Maintenance and repair costs are charged as expense in the statements of operations and comprehensive income (loss) as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets
	The Company reviews long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. An impairment loss is recognized if the estimated undiscounted future cash flow expected to result from the use and eventual disposition of an asset is less than the carrying amount. While the Company’s current and historical operating losses and cash flows are indicators of impairment, the Company believes the future cash flows to be received support the carrying value of its long-lived assets. Accordingly, the Company has not recognized any impairment losses as of March 31, 2015 and December 31, 2014.
Deferred Rent	Deferred Rent
	The Company records its costs under facility operating lease agreements as rent expense. Rent expense is recognized on a straight-line basis over the non-cancelable term of the operating lease. The difference between the actual amounts paid and amounts recorded as rent expense is recorded to deferred rent in the balance sheet.
Common Stock Warrant Liability	Common Stock Warrant Liability
	Warrants issued to common stock holders and lenders by the Company in conjunction with the 2013 financing were classified as liabilities in the accompanying condensed balance sheets, as the terms for redemption of the underlying security were outside the Company’s control. The warrants were recorded at fair value using either the Black-Scholes option pricing model, probability weighted expected return model or a binomial model, depending on the characteristics of the warrants. The fair value of these warrants is re-measured at each financial reporting period 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 based measurements of the stock 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 based measurements of options using the Black-Scholes valuation model and recognizes expense using the straight-line attribution method.
	Equity awards granted to non-employees are accounted for using the Black-Scholes valuation model to determine the fair value of such instruments. The fair value of equity awards granted to non-employees are re-measured over the related vesting period and amortized to expense as earned.
Income Taxes	Income Taxes
	The Company utilizes the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between the financial reporting and the tax bases of assets and liabilities and are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that all or part of a deferred tax asset will not be realized.
	The accounting guidance for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination based on the technical merits of the position. The Company records interest related to income taxes, if any, as interest, and any penalties would be recorded as other expense in the statements of comprehensive income (loss). There was no interest or penalties related to income taxes recorded during the three months ended March 31, 2015 and 2014.
Comprehensive Loss	Comprehensive Loss
	Comprehensive loss includes net loss and net unrealized gains and losses on marketable securities, which are presented in a single continuous statement. Accumulated other comprehensive income (loss) is disclosed in the condensed balance sheets, and is stated net of related tax effects, if any.
Net Loss Per Common Share	Net Loss Per Common Share
	Basic net loss per share of common stock is based on 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.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis
		As of March 31, 2015
		(In thousands)
	Description	Level 1			Level 2			Level 3		Fair Value
	Money market funds	$	9,660		$	—		$	—	$	9,660
	Corporate debt and asset backed securities		—			21,950			—		21,950
	Total assets measured at fair value	$	9,660		$	21,950		$	—	$	31,610
	Warrant liability	$	—		$	—		$	7,704	$	7,704
	Total liabilities measured at fair value	$	—		$	—		$	7,704	$	7,704
		As of December 31, 2014
		(In thousands)
	Description	Level 1			Level 2			Level 3		Fair Value
	Money market funds	$	9,941		$	—		$	—	$	9,941
	Corporate debt and asset backed securities		—			23,209			—		23,209
	Total assets measured at fair value	$	9,941		$	23,209		$	—	$	33,150
	Warrant liability	$	—		$	—		$	13,596	$	13,596
	Total liabilities measured at fair value	$	—		$	—		$	13,596	$	13,596
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):
		Warrant
		Liability
	Balance as of December 31, 2014	$	13,596
	Issuance of financial instrument		—
	Change in fair value		(4,575	)
	Settlement of financial instrument		(1,317	)
	Balance as of March 31, 2015	$	7,704
Computation of Loss per Share	The Company’s computation of loss per share is as follows (in thousands, except share and per share amounts):
		Three Months Ended
		March 31,
		2015			2014
	Numerator:
	Net loss allocated to common stock-basic	$	(2,328	)	$	(10,062	)
	Adjustments for revaluation of warrants		(4,575	)		—
	Net loss allocated to common stock-diluted		(6,903	)		(10,062	)
	Denominator:
	Weighted average number of common stock shares outstanding—basic		15,099,567			9,873,687
	Dilutive Securities
	Common stock warrants		643,600			—
	Weighted average number of common stock shares outstanding—diluted		15,743,167			9,873,687
	Net loss per share-basic:	$	(0.15	)	$	(1.02	)
	Net loss per share—diluted	$	(0.44	)	$	(1.02	)
Anti-Dilutive Securities Excluded from the Computation of Diluted Net Loss per Share	The following table shows the total outstanding securities considered anti-dilutive and therefore excluded from the computation of diluted net loss per share.
		Three Months
		Ended March 31,
		2015			2014
		(unaudited)
	Warrants for common stock		—			1,848
	Common stock options		1,707			907
	Incentive awards		247			—
			1,954			2,755

Certain_Balance_Sheet_Items_Ta

Certain Balance Sheet Items (Tables)	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Property and Equipment	Property and equipment consists of the following (in thousands):
		March 31,			December 31,
		2015			2014
		(unaudited)
	Office and computer equipment	$	176		$	176
	Purchased software		46			46
	Furniture and fixtures		33			33
	Leasehold improvements		66			66
	Total		321			321
	Less accumulated depreciation and amortization		(241	)		(235	)
	Property and equipment, net	$	80		$	86
Accrued Liabilities	Accrued liabilities consist of the following (in thousands):
		March 31,			December 31,
		2015			2014
		(unaudited)
	Accrued compensation	$	580		$	1,504
	Accrued pre-clinical and clinical trial expenses		1,967			1,732
	Accrued professional fees		380			73
	Other accruals		71			79
	Total accrued liabilities	$	2,998		$	3,388

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	Future minimum lease payments are as follows (in thousands):
		Lease
		Payments
	Year ending December 31:
	2015 (from April to December)		157
	2016		216
	2017		222
	2018		228
	Total future minimum payments	$	823

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Reserved Shares of Authorized but Unissued Common Stock	As of March 31, 2015 and December 31, 2014, the Company had reserved shares of authorized but unissued common stock as follows:
		March 31,		December 31,
		2015		2014
		(unaudited)
	Common stock warrants		1,592,962		1,768,347
	Equity incentive plans		2,284,421		1,549,616
	Total reserved shares of common stock		3,877,383		3,317,963

Stock_Plans_and_StockBased_Com1

Stock Plans and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock-Based Compensation Expense	Employee and director stock-based compensation expense recorded was as follows (in thousands):
		Three Months Ended
		March 31,
		2015		2014
		(unaudited)
	Research and development	$	186	$	146
	General and administrative		519		568
	Total	$	705	$	714

Organization_and_Description_o2

Organization and Description of Business - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Sep. 30, 2013
Organization And Description Of Business [Line Items]
Net loss	($2,328,000)	($10,062,000)
Cash flows from operating activities	-6,159,000	-5,011,000
Accumulated deficit	-383,087,000		-380,759,000
Cash, cash equivalents and marketable securities	32,800,000
Facility Loan Agreement [Member] | Second Tranche [Member]
Organization And Description Of Business [Line Items]
Facility loan available for drawdown	$5,000,000			$5,000,000

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$31,610	$33,150
Total liabilities measured at fair value	7,704	13,596
Warrant liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	7,704	13,596
Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	9,660	9,941
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	21,950	23,209
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	9,660	9,941
Level 1 [Member] | Money market funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	9,660	9,941
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	21,950	23,209
Level 2 [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	21,950	23,209
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	7,704	13,596
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	$7,704	$13,596

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Schedule of Changes in Fair Value of Financial Instruments (Detail) (Level 3 [Member], Warrants [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Level 3 [Member] | Warrants [Member]
Fair Value, Instruments Classified in Shareholders' Equity Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of December 31, 2014	$13,596
Issuance of financial instrument	0
Change in fair value	-4,575
Settlement of financial instrument	-1,317
Balance as of March 31, 2015	$7,704

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Product Information [Line Items]
Cash and cash equivalents, maturity description	90 days or less
Short-term contractual maturities	1 year
Restricted cash	$100,000		$100,000
Impairment losses	0		0
Interest or penalties related to income taxes	$0	$0
Minimum [Member]
Product Information [Line Items]
Property and equipment, estimated useful lives	3 years
Maximum [Member]
Product Information [Line Items]
Property and equipment, estimated useful lives	7 years

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Computation of Loss per Share (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Numerator:
Net loss allocated to common stock-basic	($2,328)	($10,062)
Adjustments for revaluation of warrants	-4,575
Net loss allocated to common stock-diluted	($6,903)	($10,062)
Denominator:
Weighted average number of common stock shares outstanding-basic	15,099,567	9,873,687
Dilutive Securities
Common stock warrants	643,600
Weighted average number of common stock shares outstanding-diluted	15,743,167	9,873,687
Net loss per share-basic:	($0.15)	($1.02)
Net loss per share-diluted	($0.44)	($1.02)

Summary_of_Significant_Account6

Summary of Significant Accounting Policies - Anti-Dilutive Securities Excluded from the Computation of Diluted Net Loss per Share (Detail)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share	1,954	2,755
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share		1,848
Common stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share	1,707	907
Incentive awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share	247

Certain_Balance_Sheet_Items_Pr

Certain Balance Sheet Items - Property and Equipment (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$321	$321
Less accumulated depreciation and amortization	-241	-235
Property and equipment, net	80	86
Office and computer equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	176	176
Purchased software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	46	46
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	33	33
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$66	$66

Certain_Balance_Sheet_Items_Ac

Certain Balance Sheet Items - Accrued Liabilities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Statement of Financial Position [Abstract]
Accrued compensation	$580	$1,504
Accrued pre-clinical and clinical trial expenses	1,967	1,732
Accrued professional fees	380	73
Other accruals	71	79
Total accrued liabilities	$2,998	$3,388

Common_Stock_Warrants_Addition

Common Stock Warrants - Additional Information (Detail) (USD $)	3 Months Ended		1 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jan. 31, 2014
Class of Warrant or Right [Line Items]
Issuance of common stock upon exercise of warrants	122,592
Issuance of common stock upon exercise of warrants on cash basis	74,136
Proceeds from warrant exercise	$426,000
Issuance of common stock upon exercise of warrants on cancellation of stock	48,456
Common stock shares cancelled	52,793
Fair value reclassification of warrant liability to additional paid-in capital	1,317,000
Proceeds from sale of common stock	4,263,000	2,402,000
Fair value of warrant liabilities			400,000
Warrants, Exercise price of $5.75 per share [Member]
Class of Warrant or Right [Line Items]
Issued warrants to purchase common stock			120,800
Proceeds from sale of common stock			$3,000,000
Exercise price of common stock			$5.75
Warrant term			5 years

Collaboration_and_License_Agre1

Collaboration and License Agreements - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Jun. 30, 1998
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License agreement date	30-Jun-98
Monthly license fees				$2,000
Potential future development payments				800,000
Development payment	0	0
Royalty payment	0	0
Janssen Pharmaceutical NV [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payments made under agreement	0		0
Royalties received	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	30-Jun-10
Number of development and license agreements	2
Contingent payment eligible to receive on development and commercial events	$228,000,000
License termination date	2015-04

Facility_Loan_Additional_Infor

Facility Loan - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2015	Jan. 31, 2014
Debt Instrument [Line Items]
Long term warrant liability			$0.40
Warrants, Exercise price of $5.00 per share [Member]
Debt Instrument [Line Items]
Warrants issued	121,739
Exercise price	$5
Long term warrant liability	0.5
Facility Loan Agreement [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	10
Facility loan, interest amortization period	36 months
Facility loan, final interest payment	0.3
Facility fee		1.00%
Facility Loan Agreement [Member] | First Tranche [Member]
Debt Instrument [Line Items]
Facility loan, drawn	5
Facility loan, fixed interest rate	8.75%
Facility Loan Agreement [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Facility loan available for drawdown	$5	5
Facility Loan Agreement [Member] | Scenario one, conversion basis [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Facility loan, fixed interest rate		8.75%
Facility Loan Agreement [Member] | Scenario two [Member] | Second Tranche [Member] | Wall Street Journal Prime Rate [Member]
Debt Instrument [Line Items]
Facility loan, prime rate plus		4.25%

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Nov. 08, 2013	Dec. 31, 2014
			sqft
Loss Contingencies [Line Items]
Rent expenses	$100,000	$200,000
Operating leases term	4 years
Lease expiration date	30-Apr-14
Accrued in the balance sheets related to indemnification obligations	0
Indemnification liabilities	$0			$0
New Lease Agreement [Member]
Loss Contingencies [Line Items]
Lease start date			16-Jan-14
Lease expiration date			31-Dec-18
Area of office space			8,894

Commitments_and_Contingencies_2

Commitments and Contingencies - Future Minimum Lease Payments (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2015 (from April to December)	$157
2016	216
2017	222
2018	228
Total future minimum payments	$823

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Common stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$0.00	$0.00

Stockholders_Equity_Reserved_S

Stockholders' Equity - Reserved Shares of Authorized but Unissued Common Stock (Detail)	Mar. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Total reserved shares of common stock	3,877,383	3,317,963
Warrants for common stock [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	1,592,962	1,768,347
Equity incentive plans [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	2,284,421	1,549,616

Stock_Plans_and_StockBased_Com2

Stock Plans and Stock-Based Compensation - Additional Information (Detail) (USD $)	0 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 03, 2014	Jan. 01, 2015	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Adjusted accrued liability to additional paid in capital	$0.10
2013 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increased in shares available for issuance		734,805
Share based compensation arrangement number of issued options			1,652,850

Stock_Plans_and_StockBased_Com3

Stock Plans and Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$705	$714
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	186	146
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$519	$568

RelatedParty_Transactions_Addi

Related-Party Transactions - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Related Party Transactions [Abstract]
Advisory fee paid to related party	$15,000	$60,000