Cymabay Therapeutics (CBAY) 10-Q 8 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
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	Accelerated Filer
Entity Common Stock, Shares Outstanding		58,768,799

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 65,581	$ 23,054
Marketable securities	163,955	74,156
Receivable from collaboration		5,000
Prepaid expenses	1,367	1,208
Other current assets	273	126
Total current assets	231,176	103,544
Property and equipment, net	103	69
Other assets	980	634
Total assets	232,259	104,247
Current liabilities:
Accounts payable	2,038	1,311
Accrued liabilities	4,976	5,757
Warrant liability	7,648	6,091
Facility loan	3,219	3,108
Accrued interest payable	37	43
Total current liabilities	17,918	16,310
Facility loan, less current portion	2,142	2,990
Total liabilities	20,060	19,300
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; 58,713,596 and 44,408,796 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	6	4
Additional paid-in capital	679,846	535,503
Accumulated other comprehensive loss	(132)	(44)
Accumulated deficit	(467,521)	(450,516)
Total stockholders’ equity	212,199	84,947
Total liabilities and stockholders’ equity	$ 232,259	$ 104,247

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
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	58,713,596	44,408,796
Common stock, shares outstanding	58,713,596	44,408,796

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Collaboration revenue		$ 4,793
Operating expenses:
Research and development	$ 9,477	4,041
General and administrative	3,373	3,701
Total operating expenses	12,850	7,742
Loss from operations	(12,850)	(2,949)
Other income (expense):
Interest income	708	37
Interest expense	(208)	(305)
Other (expense) income, net	(4,655)	(2,134)
Net loss	(17,005)	(5,351)
Net loss	(17,005)	(5,351)
Other comprehensive loss:
Unrealized loss on marketable securities	(88)	(1)
Other comprehensive loss:	(88)	(1)
Comprehensive loss	$ (17,093)	$ (5,352)
Basic net loss per common share	$ (0.32)	$ (0.20)
Diluted net loss per common share	$ (0.32)	$ (0.20)
Weighted average common shares outstanding used to calculate basic net loss per common share	53,752,753	26,609,931
Weighted average common shares outstanding used to calculate diluted net loss per common share	53,752,753	26,609,931

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net loss	$ (17,005)	$ (5,351)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	12	9
Stock-based compensation expense	1,796	1,278
Net accretion and amortization of investments in marketable securities	(278)	(1)
Non-cash interest associated with debt discount accretion	92	120
Change in fair value of warrant liability	4,654	2,134
Changes in assets and liabilities:
Accounts receivable	5,000
Other current assets	(147)	(12)
Prepaid expenses	(159)	241
Other assets	(346)
Accounts payable	727	197
Accrued liabilities	(781)	(812)
Accrued interest payable	(6)	(6)
Net cash used in operating activities	(6,441)	(2,203)
Investing activities
Purchases of property and equipment	(46)
Purchases of marketable securities	(124,943)	(9,124)
Proceeds from maturities of marketable securities	35,334	5,900
Net cash used in investing activities	(89,655)	(3,224)
Financing activities
Proceeds from issuance of common stock, net of issuance costs	135,520	9,364
Proceeds from issuance of common stock pursuant to equity award plans	3,276
Proceeds from issuance of common stock upon exercise of warrants	656
Repayment of facility loan principal	(829)	(759)
Net cash provided by financing activities	138,623	8,605
Net increase in cash and cash equivalents	42,527	3,178
Cash and cash equivalents at beginning of period	23,054	10,495
Cash and cash equivalents at end of period	65,581	13,673
Supplemental disclosure
Cash paid for interest	123	$ 192
Supplemental non-cash investing and financing activities
Issuance of common stock upon warrant exercises	$ 3,097

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2018
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 clinical-stage biopharmaceutical company focused on developing and providing access to innovative therapies for patients with liver and other chronic diseases with high unmet medical need. The Company’s two key clinical development candidates are seladelpar (MBX-8025) and arhalofenate. Seladelpar is currently being developed for the treatment of primary biliary cholangitis (PBC) and the Company is also developing seladelpar for the treatment of nonalcoholic steatohepatitis (NASH). Arhalofenate is being developed for the treatment of gout and has been out-licensed in the United States. 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, 2018, the Company incurred a net loss of $17.0 million and used $6.4 million of cash in operations. At March 31, 2018, the Company had an accumulated deficit of $467.5 million. CymaBay expects to incur substantial 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 revenue from 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, 2018, the Company’s cash, cash equivalents and marketable securities totaled $229.5 million. The Company believes these funds are sufficient to fund the Company’s current operating plan into 2021. 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 repayment of the Company’s facility loan, ongoing Phase 2b clinical trial activities in NASH, and most significantly, the timing and conduct of additional PBC development activities, including an ongoing Phase 2 clinical trial, a planned Phase 3 clinical trial, and other new drug application (NDA)-enabling studies. The Company has obtained and expects to obtain additional funding to develop its products and fund future operating losses, as appropriate, through equity offerings; debt financing; its existing license and collaboration arrangement with Kowa Pharmaceutical America, Inc (Kowa); one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights of its product candidates; or a combination of the above. It is unclear if or when any such 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 to the Company, it could have a material adverse effect on the Company’s business, results of operations, and financial condition.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying interim condensed consolidated financial statements are unaudited and are comprised of CymaBay and its wholly-owned subsidiary. These unaudited interim condensed consolidated financial statements have been prepared in accordance with 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 consolidated financial statements have been prepared on the same basis as the audited financial statements and include 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, 2017, which is contained in the Company’s Annual Report on Form 10-K as filed with the SEC on March 15, 2018. The results for the three months ended March 31, 2018 are not necessarily indicative of results to be expected for the entire year ending December 31, 2018 or future operating periods. Use of Estimates The condensed consolidated 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 consolidated 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 actual 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 revenue, stock-based compensation, accrued clinical expenses, and warrant liabilities. Fair Value of Financial Instruments The Company’s financial instruments during the periods reported consist of cash and cash equivalents, marketable securities, accounts receivable, prepaid expenses, other current assets, 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, accounts receivable, prepaid expenses, other current assets, 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—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. The following tables present the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis using the above input categories (in thousands): As of March 31, 2018 Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 45,464 $ - $ - $ 45,464 Commercial paper - 14,984 - 14,984 Asset-backed securities - 4,996 - 4,996 Total cash equivalents 45,464 19,980 - 65,444 Marketable securities: Commercial paper - 79,909 - 79,909 Corporate debt securities - 46,824 - 46,824 Asset-backed securities - 13,849 - 13,849 U.S. treasury securities - 23,373 - 23,373 Total short-term investments - 163,955 - 163,955 Total assets measured at fair value $ 45,464 $ 183,935 $ - $ 229,399 Warrant liability $ - $ - $ 7,648 $ 7,648 Total liabilities measured at fair value $ - $ - $ 7,648 $ 7,648 As of December 31, 2017 Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 12,822 $ - $ - $ 12,822 Commercial paper - 6,035 - 6,035 Total cash equivalents 12,822 6,035 - 18,857 Marketable securities: Commercial paper - 35,886 - 35,886 Corporate debt securities - 19,760 - 19,760 Asset-backed securities - 11,060 - 11,060 U.S. treasury securities - 7,450 - 7,450 Total short-term investments - 74,156 - 74,156 Total assets measured at fair value $ 12,822 $ 80,191 $ - $ 93,013 Warrant liability $ - $ - $ 6,091 $ 6,091 Total liabilities measured at fair value $ - $ - $ 6,091 $ 6,091 The Company estimates the fair value of its corporate debt, commercial paper, asset backed securities, and U.S. treasury 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 accounted for as liabilities. Beginning in September 2017, the Company changed its valuation technique and began to value its warrant liability using a Black-Scholes option pricing model, the inputs for which include: exercise price of the warrants, market price of the underlying common shares, dividend yield, expected term, expected volatility, and a risk-free interest rate. Changes to any of these inputs can have a significant impact on the estimated fair value of the warrants. Historically, the Company used a binomial option pricing model to value its warrant liabilities. The inputs for the binomial model are similar to the Black-Scholes model but also incorporate other more complex inputs that, in the Company’s case, have previously included the expected timing, probability and valuation impact of certain potential strategic events. Management concluded that no potential strategic events were expected to occur that, upon their announcement, could significantly impact the warrant liabilities valuation prior to their expiration beginning in late 2018 and ending in early 2019. 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 Three Months Ended March 30, 2018 2017 Balance, beginning of period $ 6,091 $ 1,145 Issuance of financial instruments - - Change in fair value 4,654 2,134 Settlement of financial instruments (3,097 ) - Balance, end of period $ 7,648 $ 3,279 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, demand money market accounts, corporate debt securities, and commercial paper. The Company invests excess cash in marketable securities with high credit ratings that are classified in Level 1 and Level 2 of the fair value hierarchy. These securities consist primarily of corporate debt, commercial paper, asset-backed securities, and U.S. treasury securities and are classified as “available-for-sale.” The Company considers marketable securities as short-term investments if the maturity date is less than one year from the balance sheet date. The Company considers marketable securities as long-term investments if the maturity date is in excess of one year of the balance sheet date. 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 and comprehensive loss. 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. The following tables summarize amortized cost, unrealized gain and loss, and fair value (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of March 31, 2018: Commercial paper 79,909 - - 79,909 Corporate debt securities 46,929 - (105 ) 46,824 Asset-backed securities 13,864 - (15 ) 13,849 U.S. treasury securities 23,385 - (12 ) 23,373 $ 164,087 $ - $ (132 ) $ 163,955 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of December 31, 2017: Commercial paper 35,886 - - 35,886 Corporate debt securities 19,785 - (25 ) 19,760 Asset-backed securities 11,070 - (10 ) 11,060 U.S. treasury securities 7,459 - (9 ) 7,450 $ 74,200 $ - $ (44 ) $ 74,156 Concentrations of 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 Company is exposed to credit risk in the event of a default by the financial institutions holding its cash, cash equivalents and investments and issuers of investments to the extent recorded on the balance sheets. Certain materials and key components that the Company utilizes in its operations are obtained through single suppliers. Since the suppliers of key components and materials must be named in an NDA filed with the U.S. Food and Drug Administration (FDA) for a product, significant delays can occur if the qualification of a new supplier is required. If delivery of material from the Company’s suppliers were interrupted for any reason, the Company may be unable to supply any of its product candidates for clinical trials. Revenue Recognition At the inception of an arrangement, the Company evaluates if a counterparty to a contract is a customer, if the arrangement is within the scope of revenue from contracts with customers guidance, and the term of the contract. The Company recognizes revenue when its customer obtains control of promised goods or services in a contract for an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. For contracts with customers, the Company applies the following five-step model in order to determine this amount: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. As part of the accounting for contracts with customers, the Company must develop assumptions that require judgment to determine the standalone selling price of each performance obligation identified in the contract. The Company then allocates the total transaction price to each performance obligation based on the estimated standalone selling prices of each performance obligation. The Company recognizes the amount of the transaction price as revenue that is allocated to the respective performance obligation when the performance obligation is satisfied or as it is satisfied. Generally, the Company's performance obligations are transferred to customers at a point in time, typically upon delivery. The Company enters into collaboration arrangements, under which it licenses certain rights to its intellectual property to third parties. The terms of these agreements may include payment to the Company of one or more of the following: nonrefundable, upfront license fees; development and commercial milestone payments; funding of research and/or development activities; and royalties on net sales of licensed products. Each of these types of payments are classified as collaborative revenues except for revenues from royalties on net sales of licensed products, which are classified as royalty revenues. For each collaboration agreement that results in revenues, the Company identifies all material promised goods and services, which may include a license to intellectual property and know-how, research and development activities and/or transition activities. Promised goods or services are considered to be separate performance obligations if they are distinct. In order to determine the transaction price to be allocated to each performance obligation, in addition to any upfront payment, the Company estimates the amount of variable consideration at the outset of the contract either utilizing the expected value or most likely amount method, depending on the facts and circumstances relative to the contract. The Company constrains (reduces) the estimates of variable consideration such that it is probable that a significant reversal of previously recognized revenue will not occur throughout the life of the contract. When determining if variable consideration should be constrained, management considers whether there are factors outside the Company’s control that could result in a significant reversal of revenue. In making these assessments, the Company considers the likelihood and magnitude of a potential reversal of revenue. These estimates are re-assessed each reporting period as required. Once the estimated transaction price is established, amounts are allocated to the performance obligations that have been identified. The transaction price is generally allocated to each separate performance obligation on a relative standalone selling price basis. The Company must develop assumptions that require judgment to determine the standalone selling price (SSP) in order to account for these agreements. To determine the standalone selling price the Company’s assumptions may include (i) assumptions regarding the probability of obtaining marketing approval for the drug candidate, (ii) estimates regarding the timing of and the expected costs to develop and commercialize the drug candidate, (iii) estimates of future cash flows from potential product sales with respect to the drug candidate and (iv) appropriate discount and tax rates. Standalone selling prices used to perform the initial allocation are not updated after contract inception. The Company does not include a financing component to its estimated transaction price at contract inception unless it estimates that certain performance obligations will not be satisfied within one year. Upfront License Fees: If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from nonrefundable, upfront license fees based on the relative value prescribed to the license compared to the total value of the arrangement. The revenue is recognized when the license is transferred to the collaborator and the collaborator is able to use and benefit from the license. For licenses that are not distinct from other obligations identified in the arrangement, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. If the combined performance obligation is satisfied over time, the Company applies an appropriate method of measuring progress for purposes of recognizing revenue from nonrefundable, upfront license fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Development and Regulatory Milestone Payments : Depending on facts and circumstances, the Company may conclude that it is appropriate to include the milestone in the estimated transaction price using the most likely amount method or that it is appropriate to fully constrain the milestone. A milestone payment is included in the transaction price in the reporting period that the Company concludes that it is probable that recording revenue in the period will not result in a significant reversal in amounts recognized in future periods. The Company may record revenues from certain milestones in a reporting period before the milestone is achieved if the Company concludes that achievement of the milestone is probable and that recognition of revenue related to the milestone will not result in a significant reversal in amounts recognized in future periods. The Company records a corresponding contract asset when this conclusion is reached. Milestone payments that have not been included in the transaction price to date are fully constrained. These milestones remain fully constrained until the Company concludes that achievement of the milestone is probable and that recognition of revenue related to the milestone will not result in a significant reversal in amounts recognized in future periods. The Company re-evaluates the probability of achievement of such development milestones and any related constraint each reporting period. The Company adjusts its estimate of the overall transaction price, including the amount of collaborative revenue that it has recorded, if necessary. Sales-based Milestone and Royalty Payments: The Company’s collaborators may be required to pay the Company sales-based milestone payments or royalties on future sales of commercial products. The Company recognizes revenues related to sales-based milestone and royalty payments upon the later to occur of (i) achievement of the collaborator’s underlying sales or (ii) satisfaction of any performance obligation(s) related to these sales, in each case assuming the license to the Company’s intellectual property is deemed to be the predominant item to which the sales-based milestones and/or royalties relate. Common Stock Warrant Liability The Company’s outstanding common stock warrants issued in connection with certain equity and debt financings that occurred in 2013 through 2015 are classified as liabilities in the accompanying condensed consolidated balance sheets because of certain contractual terms that preclude equity classification. The Company estimates the fair value of common stock warrants at each reporting period until the earlier of the exercise of the warrants, at which time the liability will be revalued and reclassified to stockholders’ equity, or expiration of the warrants. The determination of fair value of these common stock warrants requires management to make certain assumptions regarding subjective input variables such as timing, probability and valuation impact of certain potential strategic events, expected term, dividends, expected volatility and risk-free interest rates. If actual results are not consistent with the Company’s assumptions and judgments used in making these estimates, the Company may be required to increase or decrease other (expense) income, net, which could be material to the Company’s results of operations. Stock-Based Compensation Employee and director stock-based compensation is measured at fair value on the grant date of the award. Compensation cost is recognized as expense on a straight-line basis over the vesting period for stock options with time-based vesting and on an accelerated basis for stock options with performance conditions. For stock options with performance conditions, the Company evaluates the probability of achieving performance conditions at each reporting date. The Company begins to recognize the expense when it is deemed probable that the performance conditions will be met. The Company uses the Black-Scholes option pricing model to determine the fair value of stock option awards. The determination of fair value for stock-based awards using an option-pricing model requires management to make certain assumptions regarding subjective input variables such as expected term, dividends, volatility and risk-free interest rate. The Company is also required to make estimates as to the probability of achieving the specific performance criteria. If actual results are not consistent with the Company’s assumptions and judgments used in making these estimates, the Company may be required to increase or decrease compensation expense, which could be material to the Company’s results of operations. Equity awards granted to non-employees are valued using the Black-Scholes option pricing model. Stock-based compensation expense for nonemployee services is subject to remeasurement as the underlying equity instruments vest and is recognized as an expense over the period during which services are received. 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 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 common stock 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 common stock warrants and the presumed exercise of such securities are dilutive to net loss per share for the period, adjustments to net loss used in the calculation are required to remove the change in fair value of the common stock warrant liability 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, incentive awards and warrants were excluded from the calculation of diluted net loss per share because their effects were antidilutive. The Company’s computation of basic and diluted net loss per share is as follows (in thousands, except share and per share amounts): Three Months Ended March 31, 2018 2017 Numerator: Net loss allocated to common stock-basic $ (17,005 ) $ (5,351 ) Adjustments for revaluation of warrants - - Net loss allocated to common stock-diluted $ (17,005 ) $ (5,351 ) Denominator: Weighted average number of common stock shares outstanding - basic 53,752,753 26,609,931 Weighted average number of common stock shares outstanding - diluted 53,752,753 26,609,931 Net loss per share - basic: $ (0.32 ) $ (0.20 ) Net loss per share - diluted: $ (0.32 ) $ (0.20 ) 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 March 31, 2018 2017 Warrants for common stock 982 1,667 Common stock options 4,968 3,328 Performace-based stock options 205 327 Incentive awards 130 239 6,285 5,561 Recently Adopted Accounting Pronouncements Accounting Standards Update 2014-09 On January 1, 2018, we adopted ASU No. 2014-09, Revenue from Contracts with Customers Accounting Standards Update 2017-09 In May 2017, the Financial Accounting Standards Board (FASB) issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718)- Scope of Modification Accounting Staff Accounting Bulletin No. 118 On December 22, 2017, the U.S. federal government enacted the Tax Cuts and Jobs Act (“the Act”). The Tax Act contains, among other things, significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21% for tax years beginning after December 31, 2017, limitation of the deduction for net operating losses to 80% of current year taxable income and elimination of net operating loss carrybacks, implementing a territorial tax system, and requiring a mandatory one-time tax on U.S. owned undistributed foreign earnings and profits known as the transition tax. In December 2017, SEC staff issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act Recently Issued Accounting Pronouncements Accounting Standards Update 2016-02 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). Leases (Topic 842): Targeted Improvements Accounting Standards Update 2017-11 In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share Distinguishing Liabilities from Equity Derivatives and Hedging

Certain Balance Sheet Items

Certain Balance Sheet Items	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Certain Balance Sheet Items	3. Certain Balance Sheet Items The following table shows certain balance sheet items (in thousands): March 31, December 31, 2018 2017 (unaudited) Accrued compensation $ 867 $ 2,416 Accrued pre-clinical and clinical trial expenses 3,467 2,929 Accrued professional fees 523 288 Other accruals 119 124 Total accrued liabilities $ 4,976 $ 5,757

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration and License Agreements	4. Collaboration and License Agreements Kowa Pharmaceuticals America, Inc. On December 30, 2016, the Company entered into a license agreement with Kowa. Pursuant to the license agreement, the Company granted to Kowa an exclusive license, and right to sublicense, certain patent rights and technology related to arhalofenate. Kowa will have exclusive rights to, among other things, develop, use, manufacture, sell and otherwise exploit the licensed technology in the United States (including all possessions and territories). At Kowa’s option, the Company may also facilitate the placement of arhalofenate product manufacturing orders under the terms of the Company’s existing contract manufacturing agreements. In addition, the Company will complete specified in-process stability testing and non-clinical development services and will participate on a Joint Advisory Committee (JAC). Finally, the Company will transfer to Kowa certain arhalofenate product on hand. Under the license agreement, Kowa agreed to pay the Company a non-refundable upfront payment of $5.0 million upon contract execution. Kowa also agreed to pay the Company $5.0 million upon initiation of a study evaluating the pharmacokinetics of arhalofenate in subjects with renal impairment, which occurred during the quarter ended December 31, 2017 and was received in January 2018. An additional milestone payment of $5.0 million is due on initiation of a Phase 3 study of arhalofenate, and up to $190.0 million based upon the achievement of other specific development and sales milestones. Finally, the Company will receive tiered, double digit royalties on any product sales and a percentage of any sublicensing revenue earned by Kowa. Kowa may terminate the agreement by giving a 45 day notice to the Company three months after the effective date of the agreement and any time thereafter with a 90 day notice. Unless terminated early, the agreement has a term that ends on the later of the (i) expiration of the last to exist valid claim covering the manufacture, use and sale of arhalofenate in the United States and (ii) the 10th anniversary of the first commercial sale. The license agreement may be terminated for cause by either party based on uncured material breach by the other party, bankruptcy of the other party or for safety reasons. Upon early termination, the license and know how all revert back to the Company. The Company concluded that Kowa is a customer, and the contract is not subject to accounting literature on collaborative arrangements. This is because the Company granted to Kowa a license to its intellectual property, and provided drug product and research and pre-clinical development services, all of which are outputs of the Company’s ongoing activities, in exchange for consideration. The Company identified the following three material promises under the license agreement: 1) transfer of a license to intellectual property, inclusive of the related technology know-how conveyance and contract manufacturing rights and privileges (“license and know-how”); 2) the obligation to perform specific ongoing research and non-clinical development services, and 3) the delivery of existing on hand arhalofenate clinical product. The Company’s participation on the JAC was determined to not be a performance obligation as its participation in the JAC is not required, and is primarily for the Company’s benefit, to appraise itself of the progress of Kowa’s activities. The Company provided to Kowa standard indemnification and protection of licensed intellectual property, which is part of assurance that the license meets the contract’s specifications and is not an obligation to provide goods or services. The Company concluded that the license and know-how, the research and development services, and delivery of arhalofenate product were each by themselves distinct. The Company concluded that Kowa has the ability to benefit from the license and know-how on its own by developing and commercializing arhalofenate arhalofenate. The To allocate transaction price among the three performance obligations, the Company estimated their SSP. For the license and know-how, the SSP was estimated using the income approach based on assumptions regarding Kowa’s future revenues from the licensed intellectual property, projected costs of research and development, manufacturing and commercialization expenses, as well as the discount rate, the development timeline, and probabilities of technical and regulatory success. To estimate SSP of research and non-clinical development services and arhalofenate product on hand, the Company used a cost-plus margin approach. The Company believes that a change in the assumptions used to determine its best estimate of selling price for the performance obligations would not have a significant effect on the allocation of consideration received to the performance obligations. As of January 1, 2018, the transaction price was limited to $10.0 million, consisting of the $5.0 million due upon contract initiation and the $5.0 million triggered when Kowa initiated the study evaluating the pharmacokinetics of arhalofenate in subjects with renal impairment. Of these amounts, the Company allocated $9.5 million to the license; $0.4 million to the arhalofenate product; and $0.1 million to the research and pre-clinical development services. As of January 1, 2018, all of these performance obligations had been completed and the associated revenue had been recognized. The variable consideration related to the remaining development milestone payments has not been included in the transaction price as these were fully constrained at March 31, 2018. As part of its evaluation of the constraint, the Company considered numerous factors, including that receipt of the milestones is outside the control of the Company and contingent upon success in future clinical trials and Kowa’s efforts. Any variable consideration related to sales-based milestones (including royalties) will be recognized when the related sales occur as they were determined to relate predominantly to the license granted to Kowa. The Company will re-evaluate the The Company expensed the incremental costs of obtaining the Kowa contract prior to December 31, 2017, as substantially all costs related to the performance obligations completed by that date. Revenue recognized during the three months ended March 31, 2017 was determined in accordance with the accounting rules applicable prior to the adoption of ASC 606 on January 1, 2018. There was no difference in the revenue recognized under ASC 606 or legacy GAAP for the three months ended March 31, 2018. There were no contract assets or deferred revenues (contract liabilities) during the quarter ended March 31, 2018. Accounts receivable from the Kowa contract consisted of the following (in thousands): March 31, December 31, 2018 2017 Accounts receivable $ - $ 5,000 As of March 31, 2018, there were no amounts included in the transaction price and allocated to goods and services not yet provided. Janssen Pharmaceutical NV and Janssen Pharmaceuticals, Inc. In June 2006, the Company entered into an exclusive worldwide, royalty-bearing license to seladelpar and certain other PPARδ compounds (the PPARδ Products) with Janssen Pharmaceutical NV (Janssen NV), with the right to grant sublicenses to third parties to make, use and sell such PPARδ Products. Janssen NV has a right of first negotiation under the agreement to license a particular licensed patents covering the PPARδ 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 PPARδ Products. Under the terms of the agreement Janssen NV is entitled to receive up to an 8% royalty on net sales of PPARδ Products. 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 Type 2 diabetes and other disorders. 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, and Janssen granted the Company an exclusive, worldwide license with rights to sublicense, pursuant to the terms of one of the original agreements to continue to develop compounds with activity against an undisclosed metabolic disease target. No amounts were incurred or accrued for this agreement as of and for the three months ended March 31, 2018 and 2017. DiaTex, 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

Facility Loans

Facility Loans	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Facility Loans	5. Facility Loans 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 second tranche of $5.0 million was not drawn down by the Company and expired on June 30, 2015. At the time the first $5.0 million tranche of the 2013 Term Loan Facility 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 with a term of seven years. 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 not drawn down by the Company and expired on March 31, 2016. The modified loan terms were The first loan tranche bears interest at 8.77%, a rate that 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. For 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. 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 that include but are not limited to a material adverse change in the Company’s business, operations or condition (financial or otherwise), a material impairment of the prospect of repayment of any portion of the term loan, or a material impairment in the perfection or priority of the collateral agent’s lien in the collateral or in the value of such collateral. As of March 31, 2018, the Company was in compliance with the term loan covenants and there were no events of default.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. 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 January 15, 2019. Rent expense was $0.1 million for each of the three months ended March 31, 2018 and 2017. Future minimum lease payments are as follows (in thousands): Lease Payments Year ending December 31, 2018 (from April to December) $ 171 Total future minimum payments $ 171

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity As of March 31, 2018, and December 31, 2017, the Company had reserved shares of authorized but unissued common stock as follows: March 31, December 31, 2018 2017 (unaudited) Common stock warrants 982,456 1,460,955 Equity incentive plans 5,574,766 4,021,983 Total reserved shares of common stock 6,557,222 5,482,938 On February 1, 2018, pursuant to a

Stock Plans and Stock-Based Com

Stock Plans and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Plans and Stock-Based Compensation	8. Stock Plans and Stock-Based Compensation Stock Plans On January 1, 2018, the share reserve of the Company’s 2013 Equity Incentive Plan (2013 Plan), automatically increased by 2,220,439 shares. During the three months ended March 31, 2018, the Company granted options to purchase 1,522,272 of its common stock to its employees, directors and a consultant. As of March 31, 2018, there were 271,985 shares available for grant under the 2013 Plan. Stock-Based Compensation Expense Stock-based compensation expense recorded was as follows (in thousands): Three Months Ended March 31, 2018 2017 (unaudited) Research and development $ 649 $ 361 General and administrative 1,147 917 Total $ 1,796 $ 1,278

Related-Party Transactions

Related-Party Transactions	3 Months Ended
	Mar. 31, 2018
Related Party Transactions [Abstract]
Related-Party Transactions	9. 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 $15,000 for each of the three months ended March 31, 2018 and 2017, in monthly cash retainers.

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Event	10. Subsequent Event On April 19, 2018, the Company entered into an amended lease to extend the term of its original lease to January 15, 2024 and relocate and expand its office space within the same office park in Newark, California. The Company has an option to further extend the term of the amended lease for an additional five years, which would commence upon the expiration of the term. The lease amendment was effective as of April 16, 2018, and the Company expects to take possession of the new space in late 2018. Annual rental payments under the amended lease total approximately $0.7 million, and the Company will also pay a portion of common area and pass-through expenses.

Organization and Description 16

Organization and Description of Business (Policies)	3 Months Ended
	Mar. 31, 2018
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, 2018, the Company incurred a net loss of $17.0 million and used $6.4 million of cash in operations. At March 31, 2018, the Company had an accumulated deficit of $467.5 million. CymaBay expects to incur substantial 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 revenue from 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, 2018, the Company’s cash, cash equivalents and marketable securities totaled $229.5 million. The Company believes these funds are sufficient to fund the Company’s current operating plan into 2021. 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 repayment of the Company’s facility loan, ongoing Phase 2b clinical trial activities in NASH, and most significantly, the timing and conduct of additional PBC development activities, including an ongoing Phase 2 clinical trial, a planned Phase 3 clinical trial, and other new drug application (NDA)-enabling studies. The Company has obtained and expects to obtain additional funding to develop its products and fund future operating losses, as appropriate, through equity offerings; debt financing; its existing license and collaboration arrangement with Kowa Pharmaceutical America, Inc (Kowa); one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights of its product candidates; or a combination of the above. It is unclear if or when any such 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 to the Company, it could have a material adverse effect on the Company’s business, results of operations, and financial condition.
Basis of Presentation	Basis of Presentation The accompanying interim condensed consolidated financial statements are unaudited and are comprised of CymaBay and its wholly-owned subsidiary. These unaudited interim condensed consolidated financial statements have been prepared in accordance with 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 consolidated financial statements have been prepared on the same basis as the audited financial statements and include 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, 2017, which is contained in the Company’s Annual Report on Form 10-K as filed with the SEC on March 15, 2018. The results for the three months ended March 31, 2018 are not necessarily indicative of results to be expected for the entire year ending December 31, 2018 or future operating periods.
Use of Estimates	Use of Estimates The condensed consolidated 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 consolidated 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 actual 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 revenue, stock-based compensation, accrued clinical expenses, and warrant liabilities.
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, accounts receivable, prepaid expenses, other current assets, 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, accounts receivable, prepaid expenses, other current assets, 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—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. The following tables present the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis using the above input categories (in thousands): As of March 31, 2018 Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 45,464 $ - $ - $ 45,464 Commercial paper - 14,984 - 14,984 Asset-backed securities - 4,996 - 4,996 Total cash equivalents 45,464 19,980 - 65,444 Marketable securities: Commercial paper - 79,909 - 79,909 Corporate debt securities - 46,824 - 46,824 Asset-backed securities - 13,849 - 13,849 U.S. treasury securities - 23,373 - 23,373 Total short-term investments - 163,955 - 163,955 Total assets measured at fair value $ 45,464 $ 183,935 $ - $ 229,399 Warrant liability $ - $ - $ 7,648 $ 7,648 Total liabilities measured at fair value $ - $ - $ 7,648 $ 7,648 As of December 31, 2017 Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 12,822 $ - $ - $ 12,822 Commercial paper - 6,035 - 6,035 Total cash equivalents 12,822 6,035 - 18,857 Marketable securities: Commercial paper - 35,886 - 35,886 Corporate debt securities - 19,760 - 19,760 Asset-backed securities - 11,060 - 11,060 U.S. treasury securities - 7,450 - 7,450 Total short-term investments - 74,156 - 74,156 Total assets measured at fair value $ 12,822 $ 80,191 $ - $ 93,013 Warrant liability $ - $ - $ 6,091 $ 6,091 Total liabilities measured at fair value $ - $ - $ 6,091 $ 6,091 The Company estimates the fair value of its corporate debt, commercial paper, asset backed securities, and U.S. treasury 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 accounted for as liabilities. Beginning in September 2017, the Company changed its valuation technique and began to value its warrant liability using a Black-Scholes option pricing model, the inputs for which include: exercise price of the warrants, market price of the underlying common shares, dividend yield, expected term, expected volatility, and a risk-free interest rate. Changes to any of these inputs can have a significant impact on the estimated fair value of the warrants. Historically, the Company used a binomial option pricing model to value its warrant liabilities. The inputs for the binomial model are similar to the Black-Scholes model but also incorporate other more complex inputs that, in the Company’s case, have previously included the expected timing, probability and valuation impact of certain potential strategic events. Management concluded that no potential strategic events were expected to occur that, upon their announcement, could significantly impact the warrant liabilities valuation prior to their expiration beginning in late 2018 and ending in early 2019. 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 Three Months Ended March 30, 2018 2017 Balance, beginning of period $ 6,091 $ 1,145 Issuance of financial instruments - - Change in fair value 4,654 2,134 Settlement of financial instruments (3,097 ) - Balance, end of period $ 7,648 $ 3,279
Cash Equivalents and Marketable Securities	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, demand money market accounts, corporate debt securities, and commercial paper. The Company invests excess cash in marketable securities with high credit ratings that are classified in Level 1 and Level 2 of the fair value hierarchy. These securities consist primarily of corporate debt, commercial paper, asset-backed securities, and U.S. treasury securities and are classified as “available-for-sale.” The Company considers marketable securities as short-term investments if the maturity date is less than one year from the balance sheet date. The Company considers marketable securities as long-term investments if the maturity date is in excess of one year of the balance sheet date. 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 and comprehensive loss. 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. The following tables summarize amortized cost, unrealized gain and loss, and fair value (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of March 31, 2018: Commercial paper 79,909 - - 79,909 Corporate debt securities 46,929 - (105 ) 46,824 Asset-backed securities 13,864 - (15 ) 13,849 U.S. treasury securities 23,385 - (12 ) 23,373 $ 164,087 $ - $ (132 ) $ 163,955 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of December 31, 2017: Commercial paper 35,886 - - 35,886 Corporate debt securities 19,785 - (25 ) 19,760 Asset-backed securities 11,070 - (10 ) 11,060 U.S. treasury securities 7,459 - (9 ) 7,450 $ 74,200 $ - $ (44 ) $ 74,156
Concentrations of Risk	Concentrations of 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 Company is exposed to credit risk in the event of a default by the financial institutions holding its cash, cash equivalents and investments and issuers of investments to the extent recorded on the balance sheets. Certain materials and key components that the Company utilizes in its operations are obtained through single suppliers. Since the suppliers of key components and materials must be named in an NDA filed with the U.S. Food and Drug Administration (FDA) for a product, significant delays can occur if the qualification of a new supplier is required. If delivery of material from the Company’s suppliers were interrupted for any reason, the Company may be unable to supply any of its product candidates for clinical trials.
Revenue Recognition	Revenue Recognition At the inception of an arrangement, the Company evaluates if a counterparty to a contract is a customer, if the arrangement is within the scope of revenue from contracts with customers guidance, and the term of the contract. The Company recognizes revenue when its customer obtains control of promised goods or services in a contract for an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. For contracts with customers, the Company applies the following five-step model in order to determine this amount: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations, including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. As part of the accounting for contracts with customers, the Company must develop assumptions that require judgment to determine the standalone selling price of each performance obligation identified in the contract. The Company then allocates the total transaction price to each performance obligation based on the estimated standalone selling prices of each performance obligation. The Company recognizes the amount of the transaction price as revenue that is allocated to the respective performance obligation when the performance obligation is satisfied or as it is satisfied. Generally, the Company's performance obligations are transferred to customers at a point in time, typically upon delivery. The Company enters into collaboration arrangements, under which it licenses certain rights to its intellectual property to third parties. The terms of these agreements may include payment to the Company of one or more of the following: nonrefundable, upfront license fees; development and commercial milestone payments; funding of research and/or development activities; and royalties on net sales of licensed products. Each of these types of payments are classified as collaborative revenues except for revenues from royalties on net sales of licensed products, which are classified as royalty revenues. For each collaboration agreement that results in revenues, the Company identifies all material promised goods and services, which may include a license to intellectual property and know-how, research and development activities and/or transition activities. Promised goods or services are considered to be separate performance obligations if they are distinct. In order to determine the transaction price to be allocated to each performance obligation, in addition to any upfront payment, the Company estimates the amount of variable consideration at the outset of the contract either utilizing the expected value or most likely amount method, depending on the facts and circumstances relative to the contract. The Company constrains (reduces) the estimates of variable consideration such that it is probable that a significant reversal of previously recognized revenue will not occur throughout the life of the contract. When determining if variable consideration should be constrained, management considers whether there are factors outside the Company’s control that could result in a significant reversal of revenue. In making these assessments, the Company considers the likelihood and magnitude of a potential reversal of revenue. These estimates are re-assessed each reporting period as required. Once the estimated transaction price is established, amounts are allocated to the performance obligations that have been identified. The transaction price is generally allocated to each separate performance obligation on a relative standalone selling price basis. The Company must develop assumptions that require judgment to determine the standalone selling price (SSP) in order to account for these agreements. To determine the standalone selling price the Company’s assumptions may include (i) assumptions regarding the probability of obtaining marketing approval for the drug candidate, (ii) estimates regarding the timing of and the expected costs to develop and commercialize the drug candidate, (iii) estimates of future cash flows from potential product sales with respect to the drug candidate and (iv) appropriate discount and tax rates. Standalone selling prices used to perform the initial allocation are not updated after contract inception. The Company does not include a financing component to its estimated transaction price at contract inception unless it estimates that certain performance obligations will not be satisfied within one year. Upfront License Fees: If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from nonrefundable, upfront license fees based on the relative value prescribed to the license compared to the total value of the arrangement. The revenue is recognized when the license is transferred to the collaborator and the collaborator is able to use and benefit from the license. For licenses that are not distinct from other obligations identified in the arrangement, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. If the combined performance obligation is satisfied over time, the Company applies an appropriate method of measuring progress for purposes of recognizing revenue from nonrefundable, upfront license fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. Development and Regulatory Milestone Payments : Depending on facts and circumstances, the Company may conclude that it is appropriate to include the milestone in the estimated transaction price using the most likely amount method or that it is appropriate to fully constrain the milestone. A milestone payment is included in the transaction price in the reporting period that the Company concludes that it is probable that recording revenue in the period will not result in a significant reversal in amounts recognized in future periods. The Company may record revenues from certain milestones in a reporting period before the milestone is achieved if the Company concludes that achievement of the milestone is probable and that recognition of revenue related to the milestone will not result in a significant reversal in amounts recognized in future periods. The Company records a corresponding contract asset when this conclusion is reached. Milestone payments that have not been included in the transaction price to date are fully constrained. These milestones remain fully constrained until the Company concludes that achievement of the milestone is probable and that recognition of revenue related to the milestone will not result in a significant reversal in amounts recognized in future periods. The Company re-evaluates the probability of achievement of such development milestones and any related constraint each reporting period. The Company adjusts its estimate of the overall transaction price, including the amount of collaborative revenue that it has recorded, if necessary. Sales-based Milestone and Royalty Payments: The Company’s collaborators may be required to pay the Company sales-based milestone payments or royalties on future sales of commercial products. The Company recognizes revenues related to sales-based milestone and royalty payments upon the later to occur of (i) achievement of the collaborator’s underlying sales or (ii) satisfaction of any performance obligation(s) related to these sales, in each case assuming the license to the Company’s intellectual property is deemed to be the predominant item to which the sales-based milestones and/or royalties relate.
Common Stock Warrant Liability	Common Stock Warrant Liability The Company’s outstanding common stock warrants issued in connection with certain equity and debt financings that occurred in 2013 through 2015 are classified as liabilities in the accompanying condensed consolidated balance sheets because of certain contractual terms that preclude equity classification. The Company estimates the fair value of common stock warrants at each reporting period until the earlier of the exercise of the warrants, at which time the liability will be revalued and reclassified to stockholders’ equity, or expiration of the warrants. The determination of fair value of these common stock warrants requires management to make certain assumptions regarding subjective input variables such as timing, probability and valuation impact of certain potential strategic events, expected term, dividends, expected volatility and risk-free interest rates. If actual results are not consistent with the Company’s assumptions and judgments used in making these estimates, the Company may be required to increase or decrease other (expense) income, net, which could be material to the Company’s results of operations.
Stock-Based Compensation	Stock-Based Compensation Employee and director stock-based compensation is measured at fair value on the grant date of the award. Compensation cost is recognized as expense on a straight-line basis over the vesting period for stock options with time-based vesting and on an accelerated basis for stock options with performance conditions. For stock options with performance conditions, the Company evaluates the probability of achieving performance conditions at each reporting date. The Company begins to recognize the expense when it is deemed probable that the performance conditions will be met. The Company uses the Black-Scholes option pricing model to determine the fair value of stock option awards. The determination of fair value for stock-based awards using an option-pricing model requires management to make certain assumptions regarding subjective input variables such as expected term, dividends, volatility and risk-free interest rate. The Company is also required to make estimates as to the probability of achieving the specific performance criteria. If actual results are not consistent with the Company’s assumptions and judgments used in making these estimates, the Company may be required to increase or decrease compensation expense, which could be material to the Company’s results of operations. Equity awards granted to non-employees are valued using the Black-Scholes option pricing model. Stock-based compensation expense for nonemployee services is subject to remeasurement as the underlying equity instruments vest and is recognized as an expense over the period during which services are received.
Net Income (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 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 common stock 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 common stock warrants and the presumed exercise of such securities are dilutive to net loss per share for the period, adjustments to net loss used in the calculation are required to remove the change in fair value of the common stock warrant liability 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, incentive awards and warrants were excluded from the calculation of diluted net loss per share because their effects were antidilutive. The Company’s computation of basic and diluted net loss per share is as follows (in thousands, except share and per share amounts): Three Months Ended March 31, 2018 2017 Numerator: Net loss allocated to common stock-basic $ (17,005 ) $ (5,351 ) Adjustments for revaluation of warrants - - Net loss allocated to common stock-diluted $ (17,005 ) $ (5,351 ) Denominator: Weighted average number of common stock shares outstanding - basic 53,752,753 26,609,931 Weighted average number of common stock shares outstanding - diluted 53,752,753 26,609,931 Net loss per share - basic: $ (0.32 ) $ (0.20 ) Net loss per share - diluted: $ (0.32 ) $ (0.20 ) 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 March 31, 2018 2017 Warrants for common stock 982 1,667 Common stock options 4,968 3,328 Performace-based stock options 205 327 Incentive awards 130 239 6,285 5,561
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements Accounting Standards Update 2014-09 On January 1, 2018, we adopted ASU No. 2014-09, Revenue from Contracts with Customers Accounting Standards Update 2017-09 In May 2017, the Financial Accounting Standards Board (FASB) issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718)- Scope of Modification Accounting Staff Accounting Bulletin No. 118 On December 22, 2017, the U.S. federal government enacted the Tax Cuts and Jobs Act (“the Act”). The Tax Act contains, among other things, significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21% for tax years beginning after December 31, 2017, limitation of the deduction for net operating losses to 80% of current year taxable income and elimination of net operating loss carrybacks, implementing a territorial tax system, and requiring a mandatory one-time tax on U.S. owned undistributed foreign earnings and profits known as the transition tax. In December 2017, SEC staff issued Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act Recently Issued Accounting Pronouncements Accounting Standards Update 2016-02 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). Leases (Topic 842): Targeted Improvements Accounting Standards Update 2017-11 In July 2017, the FASB issued ASU No. 2017-11, Earnings Per Share Distinguishing Liabilities from Equity Derivatives and Hedging

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis	The following tables present the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis using the above input categories (in thousands): As of March 31, 2018 Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 45,464 $ - $ - $ 45,464 Commercial paper - 14,984 - 14,984 Asset-backed securities - 4,996 - 4,996 Total cash equivalents 45,464 19,980 - 65,444 Marketable securities: Commercial paper - 79,909 - 79,909 Corporate debt securities - 46,824 - 46,824 Asset-backed securities - 13,849 - 13,849 U.S. treasury securities - 23,373 - 23,373 Total short-term investments - 163,955 - 163,955 Total assets measured at fair value $ 45,464 $ 183,935 $ - $ 229,399 Warrant liability $ - $ - $ 7,648 $ 7,648 Total liabilities measured at fair value $ - $ - $ 7,648 $ 7,648 As of December 31, 2017 Description Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 12,822 $ - $ - $ 12,822 Commercial paper - 6,035 - 6,035 Total cash equivalents 12,822 6,035 - 18,857 Marketable securities: Commercial paper - 35,886 - 35,886 Corporate debt securities - 19,760 - 19,760 Asset-backed securities - 11,060 - 11,060 U.S. treasury securities - 7,450 - 7,450 Total short-term investments - 74,156 - 74,156 Total assets measured at fair value $ 12,822 $ 80,191 $ - $ 93,013 Warrant liability $ - $ - $ 6,091 $ 6,091 Total liabilities measured at fair value $ - $ - $ 6,091 $ 6,091
Schedule of Changes in Fair Value of Liabilities	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 Three Months Ended March 30, 2018 2017 Balance, beginning of period $ 6,091 $ 1,145 Issuance of financial instruments - - Change in fair value 4,654 2,134 Settlement of financial instruments (3,097 ) - Balance, end of period $ 7,648 $ 3,279
Schedule of Amortized Cost, Unrealized Gain and Loss, and Fair Value	The following tables summarize amortized cost, unrealized gain and loss, and fair value (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of March 31, 2018: Commercial paper 79,909 - - 79,909 Corporate debt securities 46,929 - (105 ) 46,824 Asset-backed securities 13,864 - (15 ) 13,849 U.S. treasury securities 23,385 - (12 ) 23,373 $ 164,087 $ - $ (132 ) $ 163,955 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of December 31, 2017: Commercial paper 35,886 - - 35,886 Corporate debt securities 19,785 - (25 ) 19,760 Asset-backed securities 11,070 - (10 ) 11,060 U.S. treasury securities 7,459 - (9 ) 7,450 $ 74,200 $ - $ (44 ) $ 74,156
Computation of Basic and Diluted Net Loss per Share	In all periods presented, the Company’s outstanding stock options, incentive awards and warrants were excluded from the calculation of diluted net loss per share because their effects were antidilutive. The Company’s computation of basic and diluted net loss per share is as follows (in thousands, except share and per share amounts): Three Months Ended March 31, 2018 2017 Numerator: Net loss allocated to common stock-basic $ (17,005 ) $ (5,351 ) Adjustments for revaluation of warrants - - Net loss allocated to common stock-diluted $ (17,005 ) $ (5,351 ) Denominator: Weighted average number of common stock shares outstanding - basic 53,752,753 26,609,931 Weighted average number of common stock shares outstanding - diluted 53,752,753 26,609,931 Net loss per share - basic: $ (0.32 ) $ (0.20 ) Net loss per share - diluted: $ (0.32 ) $ (0.20 )
Anti-Dilutive Securities 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 March 31, 2018 2017 Warrants for common stock 982 1,667 Common stock options 4,968 3,328 Performace-based stock options 205 327 Incentive awards 130 239 6,285 5,561

Certain Balance Sheet Items (Ta

Certain Balance Sheet Items (Tables)	3 Months Ended
	Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accrued Liabilities	The following table shows certain balance sheet items (in thousands): March 31, December 31, 2018 2017 (unaudited) Accrued compensation $ 867 $ 2,416 Accrued pre-clinical and clinical trial expenses 3,467 2,929 Accrued professional fees 523 288 Other accruals 119 124 Total accrued liabilities $ 4,976 $ 5,757

Collaboration and License Agr19

Collaboration and License Agreements (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue From Contract With Customer [Abstract]
Accounts Receivable from the Kowa Contract	There were no contract assets or deferred revenues (contract liabilities) during the quarter ended March 31, 2018. Accounts receivable from the Kowa contract consisted of the following (in thousands): March 31, December 31, 2018 2017 Accounts receivable $ - $ 5,000

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	Future minimum lease payments are as follows (in thousands): Lease Payments Year ending December 31, 2018 (from April to December) $ 171 Total future minimum payments $ 171

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Reserved Shares of Authorized but Unissued Common Stock	As of March 31, 2018, and December 31, 2017, the Company had reserved shares of authorized but unissued common stock as follows: March 31, December 31, 2018 2017 (unaudited) Common stock warrants 982,456 1,460,955 Equity incentive plans 5,574,766 4,021,983 Total reserved shares of common stock 6,557,222 5,482,938

Stock Plans and Stock-Based C22

Stock Plans and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-Based Compensation Expense	Stock-based compensation expense recorded was as follows (in thousands): Three Months Ended March 31, 2018 2017 (unaudited) Research and development $ 649 $ 361 General and administrative 1,147 917 Total $ 1,796 $ 1,278

Organization and Description 23

Organization and Description of Business - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)Segment	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segments | Segment	1
Net loss	$ (17,005)	$ (5,351)
Cash flows from operating activities	(6,441)	$ (2,203)
Accumulated deficit	(467,521)		$ (450,516)
Cash and cash equivalents and marketable securities	$ 229,500

Summary of Significant Accoun24

Summary of Significant Accounting Policies - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 229,399	$ 93,013
Total liabilities measured at fair value	7,648	6,091
Warrant Liability [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	7,648	6,091
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	45,464	12,822
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	183,935	80,191
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities measured at fair value	7,648	6,091
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	7,648	6,091
Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	65,444	18,857
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	45,464	12,822
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	14,984	6,035
Cash Equivalents [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	4,996
Cash Equivalents [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	45,464	12,822
Cash Equivalents [Member] | 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	45,464	12,822
Cash Equivalents [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	19,980	6,035
Cash Equivalents [Member] | Level 2 [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	14,984	6,035
Cash Equivalents [Member] | Level 2 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	4,996
Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	163,955	74,156
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	79,909	35,886
Short-term Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	13,849	11,060
Short-term Investments [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	46,824	19,760
Short-term Investments [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	23,373	7,450
Short-term Investments [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	163,955	74,156
Short-term Investments [Member] | Level 2 [Member] | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	79,909	35,886
Short-term Investments [Member] | Level 2 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	13,849	11,060
Short-term Investments [Member] | Level 2 [Member] | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	46,824	19,760
Short-term Investments [Member] | Level 2 [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 23,373	$ 7,450

Summary of Significant Accoun25

Summary of Significant Accounting Policies - Schedule of Changes in Fair Value of Liabilities (Detail) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Fair Value, Instruments Classified in Shareholders' Equity Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 6,091	$ 1,145
Change in fair value	4,654	2,134
Settlement of financial instruments	(3,097)
Balance, end of period	$ 7,648	$ 3,279

Summary of Significant Accoun26

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Product Information [Line Items]
Cash and cash equivalents, maturity description	90 days or less
US federal corporate tax rate	21.00%	35.00%
Limitation of the deduction for net operating losses	80.00%
Provisional amounts measurement period	1 year
Maximum [Member]
Product Information [Line Items]
Short-term contractual maturities	1 year
Minimum [Member]
Product Information [Line Items]
Long-term contractual maturities	1 year

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Schedule of Amortized Cost, Unrealized Gain and Loss, and Fair Value (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	$ 164,087	$ 74,200
Gross Unrealized Losses	(132)	(44)
Estimated Fair Value	163,955	74,156
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	79,909	35,886
Estimated Fair Value	79,909	35,886
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	46,929	19,785
Gross Unrealized Losses	(105)	(25)
Estimated Fair Value	46,824	19,760
Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	13,864	11,070
Gross Unrealized Losses	(15)	(10)
Estimated Fair Value	13,849	11,060
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized Cost	23,385	7,459
Gross Unrealized Losses	(12)	(9)
Estimated Fair Value	$ 23,373	$ 7,450

Summary of Significant Accoun28

Summary of Significant Accounting Policies - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net loss allocated to common stock-basic	$ (17,005)	$ (5,351)
Net loss allocated to common stock-diluted	$ (17,005)	$ (5,351)
Denominator:
Weighted average number of common stock shares outstanding - basic	53,752,753	26,609,931
Weighted average number of common stock shares outstanding - diluted	53,752,753	26,609,931
Net loss per share - basic:	$ (0.32)	$ (0.20)
Net loss per share - diluted:	$ (0.32)	$ (0.20)

Summary of Significant Accoun29

Summary of Significant Accounting Policies - Anti-Dilutive Securities Excluded from the Computation of Diluted Net Loss per Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share	6,285	5,561
Common Stock 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	982	1,667
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	4,968	3,328
Performance Based Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share	205	327
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	130	239

Certain Balance Sheet Items - A

Certain Balance Sheet Items - Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Accrued compensation	$ 867	$ 2,416
Accrued pre-clinical and clinical trial expenses	3,467	2,929
Accrued professional fees	523	288
Other accruals	119	124
Total accrued liabilities	$ 4,976	$ 5,757

Collaboration and License Agr31

Collaboration and License Agreements - Additional Information (Detail)	1 Months Ended		3 Months Ended
	Jun. 30, 2010Agreement	Jun. 30, 2006	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Mar. 31, 2017USD ($)	Jan. 01, 2018USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligations						$ 10,000,000
Contract assets			$ 0
Contract liabilities			0
Contract Initiation [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligations						5,000,000
License [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligations						9,500,000
Arhalofenate Product [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligations						400,000
Research and Pre Clinical Development Services [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligations						100,000
Pharmacokinetics of Arhalofenate [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligations						$ 5,000,000
Kowa Pharmaceuticals America Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable upfront payment				$ 5,000,000
Kowa Pharmaceuticals America Inc [Member] | Pharmacokinetics of Arhalofenate [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments				5,000,000
Kowa Pharmaceuticals America Inc [Member] | Phase 3 Study [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments				5,000,000
Kowa Pharmaceuticals America Inc [Member] | Achievement of Other Specific Development and Sales [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments				190,000,000
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]
Number of development and license agreements | Agreement	2
Royalty payment			0	0
Accrued royalties			0	$ 0
DiaTex, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty payment			0		$ 0
Development payment			$ 0		$ 0

Collaboration and License Agr32

Collaboration and License Agreements - Accounts Receivable from the Kowa Contract (Detail) $ in Thousands	Dec. 31, 2017USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accounts receivable	$ 5,000
Kowa Pharmaceuticals America Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accounts receivable	$ 5,000

Facility Loans - Additional Inf

Facility Loans - Additional Information (Detail) - USD ($)	Aug. 07, 2015	Sep. 30, 2013	Mar. 31, 2018
Debt Instrument [Line Items]
Issued warrants to purchase common stock			114,436
Exercise price of common stock			$ 2.84
Warrant term			10 years
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
Warrant term			7 years
2013 Term Loan Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 10,000,000
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
2013 Term Loan Facility [Member] | Second Tranche [Member]
Debt Instrument [Line Items]
Facility loan available for draw down		$ 5,000,000
Facility loan expiration date		Jun. 30, 2015
2015 Term Loan Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 15,000,000
Debt instrument payment terms			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] | 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] | Minimum [Member] | Wall Street Journal Prime Rate [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
Facility loan expiration date	Mar. 31, 2016

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Nov. 08, 2013ft²	Mar. 31, 2018USD ($)	Mar. 31, 2017USD ($)
Loss Contingencies [Line Items]
Rent expenses | $		$ 0.1	$ 0.1
Lease Facility [Member]
Loss Contingencies [Line Items]
Area of office space | ft²	8,894
Lease start date	Jan. 16, 2014
Lease expiration date	Jan. 15, 2019

Commitments and Contingencies35

Commitments and Contingencies - Future Minimum Lease Payments (Detail) $ in Thousands	Mar. 31, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2018 (from April to December)	$ 171
Total future minimum payments	$ 171

Stockholder's Equity - Reserved

Stockholder's Equity - Reserved Shares of Authorized but Unissued Common Stock (Detail) - shares	Mar. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Total reserved shares of common stock	6,557,222	5,482,938
Common Stock Warrants [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	982,456	1,460,955
Equity Incentive Plans [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	5,574,766	4,021,983

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Feb. 01, 2018	Mar. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Common stock, shares issued	13,340,000	58,713,596	44,408,796
Common stock offering price	$ 10.80
Net proceeds from public offering	$ 135.5

Stock Plans and Stock-Based C38

Stock Plans and Stock-Based Compensation - Additional Information (Detail) - 2013 Equity Incentive Plan [Member]	3 Months Ended
	Mar. 31, 2018shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increased in shares available for issuance	2,220,439
Shares available for grant	271,985
Employees, Directors and Consultant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options to purchase common stock granted	1,522,272

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
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,796	$ 1,278
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	649	361
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,147	$ 917

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Former Member of Board of Directors [Member]
Related Party Transaction [Line Items]
Advisory fee paid to related party	$ 15,000	$ 15,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event [Member] $ in Millions	Apr. 19, 2018USD ($)
Subsequent Event [Line Items]
Lease expiration date	Jan. 15, 2024
Lease term, option to renew period	5 years
Lease amendment effective date	Apr. 16, 2018
Annual rental payments under the amended lease	$ 0.7