Cymabay Therapeutics (CBAY) 10-Q 8 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	CBAY
Entity Registrant Name	CYMABAY THERAPEUTICS, INC.
Entity Central Index Key	0001042074
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		68,696,043

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 125,574	$ 48,995
Marketable securities	139,182	129,669
Accrued interest receivable	481	304
Prepaid expenses	4,827	2,594
Total current assets	270,064	181,562
Property and equipment, net	2,794	2,905
Operating lease right-of-use asset	177
Other assets	1,122	2,280
Total assets	274,157	186,747
Current liabilities:
Accounts payable	2,410	1,973
Accrued clinical trial expenses	9,281	8,588
Other accrued liabilities	2,782	3,854
Total current liabilities	14,473	14,415
Long-term portion of operating lease liability	2,053
Other liabilities		1,914
Total liabilities	16,526	16,329
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.0001 par value: 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value: 100,000,000 shares authorized; 68,694,043 and 59,456,493 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively	7	6
Additional paid-in capital	803,718	693,534
Accumulated other comprehensive income (loss)	45	(58)
Accumulated deficit	(546,139)	(523,064)
Total stockholders’ equity	257,631	170,418
Total liabilities and stockholders’ equity	$ 274,157	$ 186,747

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
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	68,694,043	59,456,493
Common stock, shares outstanding	68,694,043	59,456,493

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating expenses:
Research and development	$ 18,588	$ 9,477
General and administrative	5,663	3,373
Total operating expenses	24,251	12,850
Loss from operations	(24,251)	(12,850)
Other income (expense):
Interest income	1,176	708
Interest expense		(208)
Other expense, net		(4,655)
Total other income (expense)	1,176	(4,155)
Net loss	(23,075)	(17,005)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities	103	(88)
Total other comprehensive income (loss)	103	(88)
Comprehensive loss	$ (22,972)	$ (17,093)
Basic net loss per common share	$ (0.37)	$ (0.32)
Diluted net loss per common share	$ (0.37)	$ (0.32)
Weighted average common shares outstanding used to calculate basic net loss per common share	61,890,632	53,752,753
Weighted average common shares outstanding used to calculate diluted net loss per common share	61,890,632	53,752,753

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net loss	$ (23,075)	$ (17,005)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	138	12
Stock-based compensation expense	2,342	1,796
Net accretion and amortization of investments in marketable securities	(544)	(278)
Non-cash interest associated with debt discount accretion		92
Change in fair value of warrant liability		4,654
Changes in assets and liabilities:
Receivable from collaboration		5,000
Interest receivable and other current assets	(177)	(147)
Prepaid expenses	(2,233)	(159)
Other assets	1,158	(346)
Accounts payable	437	727
Accrued liabilities	(440)	(781)
Accrued interest payable		(6)
Net cash used in operating activities	(22,394)	(6,441)
Investing activities
Purchases of property and equipment	(178)	(46)
Purchases of marketable securities	(90,897)	(124,943)
Proceeds from maturities of marketable securities	78,051	35,334
Proceeds from sale of marketable securities	3,980
Net cash used in investing activities	(9,044)	(89,655)
Financing activities
Proceeds from issuance of common stock, net of issuance costs	107,920	135,520
Proceeds from issuance of common stock pursuant to equity award plans	97	3,276
Proceeds from issuance of common stock upon exercise of warrants		656
Repayment of facility loan principal		(829)
Net cash provided by financing activities	108,017	138,623
Net increase in cash and cash equivalents	76,579	42,527
Cash and cash equivalents at beginning of period	48,995	23,054
Cash and cash equivalents at end of period	125,574	65,581
Supplemental disclosure
Cash paid for interest		123
Supplemental non-cash investing and financing activities
Accrued financing costs	$ 174
Issuance of common stock upon warrant exercises		$ 3,097

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Balance at beginning of period at Dec. 31, 2017	$ 84,947	$ 4	$ 535,503	$ (44)	$ (450,516)
Balance at beginning of period (in shares) at Dec. 31, 2017		44,408,796
Issuance of common stock upon exercise of stock options and incentive awards	3,276		3,276
Issuance of common stock upon exercise of stock options and incentive awards (Shares)		667,656
Issuance of common stock upon exercise of warrants, value	3,753		3,753
Issuance of common stock upon exercise of warrants (Shares)		297,144
Stock-based compensation expense	1,796		1,796
Issuance of common stock, value	135,520	$ 2	135,518
Issuance of common stock, (in shares)		13,340,000
Net loss	(17,005)				(17,005)
Net unrealized gain (loss) on marketable securities	(88)			(88)
Balance at end of period at Mar. 31, 2018	212,199	$ 6	679,846	(132)	(467,521)
Balance at end of period (in shares) at Mar. 31, 2018		58,713,596
Balance at beginning of period at Dec. 31, 2018	170,418	$ 6	693,534	(58)	(523,064)
Balance at beginning of period (in shares) at Dec. 31, 2018		59,456,493
Issuance of common stock upon exercise of stock options and incentive awards	97		97
Issuance of common stock upon exercise of stock options and incentive awards (Shares)		37,550
Stock-based compensation expense	2,342		2,342
Issuance of common stock, value	107,746	$ 1	107,745
Issuance of common stock, (in shares)		9,200,000
Net loss	(23,075)				(23,075)
Net unrealized gain (loss) on marketable securities	103			103
Balance at end of period at Mar. 31, 2019	$ 257,631	$ 7	$ 803,718	$ 45	$ (546,139)
Balance at end of period (in shares) at Mar. 31, 2019		68,694,043

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Stockholders Equity [Abstract]
Stock issuance cost	$ 7,254	$ 8,553

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2019
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 key clinical development candidate is seladelpar (MBX-8025). Seladelpar is currently being developed for the treatment of the liver diseases primary biliary cholangitis (PBC) and nonalcoholic steatohepatitis (NASH). 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, 2019, the Company incurred a net loss of $23.1 million and used $22.4 million of cash in operations. At March 31, 2019, the Company had an accumulated deficit of $546.1 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, 2019, the Company had cash, cash equivalents and marketable securities totaling $264.8 million which the Company believes is 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 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 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; 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, 2019
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 subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company has no unconsolidated subsidiaries or investments accounted for under the equity method. These unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. 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, 2018, which is contained in the Company’s Annual Report on Form 10-K as filed with the SEC on February 28, 2019. The results for the three months ended March 31, 2019 are not necessarily indicative of results to be expected for the entire year ending December 31, 2019 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 the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Actual results could differ materially from those estimates and assumptions. The Company believes significant judgment can be involved in estimating stock-based compensation, accrued clinical expenses, and the fair value of the Company’s common stock warrants. These estimates form the basis for making judgments about the carrying values of assets and liabilities when these values are not readily apparent from other sources. Estimates are assessed each reporting period and updated to reflect current information and any changes in estimates will be reflected in the period first identified. 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. 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, 2019 Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 113,114 $ - $ - $ 113,114 U.S. commercial paper - 3,481 - 3,481 Total cash equivalents 113,114 3,481 - 116,595 Marketable securities: U.S. and foreign commercial paper - 52,158 - 52,158 U.S. and foreign corporate debt securities - 38,318 - 38,318 Asset-backed securities - 25,400 - 25,400 U.S. treasury securities - 23,306 - 23,306 Total short-term investments - 139,182 - 139,182 Total assets measured at fair value $ 113,114 $ 142,663 $ - $ 255,777 As of December 31, 2018 Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 39,481 $ - $ - $ 39,481 U.S. and foreign commercial paper - 6,469 - 6,469 Total cash equivalents 39,481 6,469 - 45,950 Marketable securities: U.S. and foreign commercial paper - 51,627 - 51,627 U.S. and foreign corporate debt securities - 34,634 - 34,634 Asset-backed securities - 25,472 - 25,472 U.S. treasury securities - 17,936 - 17,936 Total short-term investments - 129,669 - 129,669 Total assets measured at fair value $ 39,481 $ 136,138 $ - $ 175,619 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. Historically, the Company held 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 were accounted for as liabilities until either they were exercised or expired in September 2018. The Company used a binomial option pricing model to value its warrant liabilities prior to September 2017. 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, included the expected timing, probability and valuation impact of certain potential strategic events. 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. The following table sets forth a summary of the changes in the fair value of the Company’s liabilities measured using Level 3 inputs (in thousands): For the Three Months Ended March 31, 2019 2018 Balance, beginning of period $ - $ 6,091 Change in fair value - 4,654 Settlement of financial instruments - (3,097 ) Balance, end of period $ - $ 7,648 Cash, 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, 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 or equal to 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 condensed consolidated statements of operations and comprehensive loss. Unrealized holding gains and losses are reported in accumulated other comprehensive loss in the condensed consolidated 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 of the Company’s available for sale marketable securities (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of March 31, 2019: U.S. and foreign commercial paper $ 52,158 $ - $ - $ 52,158 U.S. and foreign corporate debt securities 38,289 29 - 38,318 Asset-backed securities 25,395 6 (1 ) 25,400 U.S. treasury securities 23,295 11 - 23,306 $ 139,137 $ 46 $ (1 ) $ 139,182 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of December 31, 2018: U.S. and foreign commercial paper $ 51,627 $ - $ - $ 51,627 U.S. and foreign corporate debt securities 34,668 - (34 ) 34,634 Asset-backed securities 25,494 - (22 ) 25,472 U.S. treasury securities 17,938 - (2 ) 17,936 $ 129,727 $ - $ (58 ) $ 129,669 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 condensed consolidated 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 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. Leases The Company has one lease, a non-cancelable operating lease agreement for its corporate offices. Prior to January 1, 2019, the Company recognized related rent expense on a straight-line basis over the term of the lease. Incentives granted under the Company’s facilities lease, including allowances for leasehold improvements and rent holidays, were recognized as reductions to rental expense on a straight-line basis over the term of the lease. Deferred rent consisted of the difference between cash payments and the rent expense recognized. Subsequent to the adoption of the new leasing standard on January 1, 2019, the Company recognizes a lease asset for its right to use the underlying asset and a lease liability for the corresponding lease obligation. The Company determines whether an arrangement is or contains a lease at contract inception. Operating leases are included in operating lease right-of-use assets, other accrued liabilities, and long-term portion of operating lease liabilities in our condensed consolidated balance sheet at March 31, 2019. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the net present value of lease payments, the Company uses its incremental borrowing rate based on the information available at the lease commencement date. The incremental borrowing rate represents the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of a lease. The Company considers a lease term to be the noncancelable period that it has the right to use the underlying asset, including any periods where it is reasonably assured the Company will exercise the option to extend the contract. Periods covered by an option to extend are included in the lease term if the lessor controls the exercise of that option. The operating lease right-of-use assets also include any lease payments made and exclude lease incentives. Lease expense is recognized on a straight-line basis over the expected lease term. The Company has elected to not separate lease and non-lease components for its leased assets and accounts for all lease and non-lease components of its agreements as a single lease component. Common Stock Warrant Liability Historically, the Company’s outstanding common stock warrants issued in connection with certain equity and debt financings that occurred in 2013 through 2015 were classified as liabilities in the accompanying condensed consolidated balance sheets because of certain contractual terms that preclude equity classification. As of September 30, 2018, all outstanding warrants related to these financings had been exercised or had expired. Upon expiration, the remaining fair value of the liability was extinguished and credited to other income (expense), net in the Company’s condensed consolidated statement of operations. Prior to expiration, the Company estimated the fair value of common stock warrants at each reporting period until the exercise of the warrants, at which time the liability was revalued and reclassified to stockholders’ equity. The determination of fair value of these common stock warrants required 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. Research and Development Expenses Research and development expenses consist of costs incurred in identifying, developing, and testing product candidates. These expenses consist primarily of costs for research and development personnel, including related stock-based compensation; contract research organizations (CRO) and other third parties that assist in managing, monitoring, and analyzing clinical trials; investigator and site fees; laboratory services; consultants; contract manufacturing services; non-clinical studies, including materials; and allocated expenses, such as depreciation of assets, and facilities and information technology that support research and development activities. Research and development costs are expensed as incurred, including expenses that may or may not be reimbursed under research and development funding arrangements. Payments made prior to the receipt of goods or services to be used in research and development are recorded as prepaid assets until the goods are received or services are rendered. Such payments are evaluated for current or long term classification based on when they will be realized. The Company records expenses related to clinical studies and manufacturing development activities based on its estimates of the services received and efforts expended pursuant to contracts with multiple CROs and manufacturing vendors that conduct and manage these activities on its behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract, and may result in uneven payment flows. There may be instances in which payments made to the Company’s vendors will exceed the level of services provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of subjects and the completion of clinical trial milestones. In amortizing or accruing service fees, the Company estimates the time period over which services will be performed, enrollment of subjects, number of sites activated and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the Company’s estimate, the Company will adjust the accrued or prepaid expense balance accordingly. To date, there have been no material differences from the Company’s estimates to the amounts actually incurred. 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 options 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 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 has historically been subject to remeasurement at each reporting date as the underlying equity instruments vest and was recognized as an expense over the period during which services are received. Upon the adoption of ASU 2018-07, Compensation – Stock Compensation Net Loss Per Common Share Basic net loss per share of common stock is based on the weighted average number of shares of common stock outstanding equivalents during the period. Diluted net loss per share of common stock is calculated as the weighted average number of shares of common stock outstanding adjusted to include the assumed exercises of stock options and 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 and actual exercise or expiration of such securities are dilutive to earnings (net loss) per share for the period, adjustments to net income or net loss used in the calculation are required to remove the change in fair value of the 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 were excluded from the calculation of diluted net loss per share because their effects were antidilutive. The following table sets forth the computation of basic and diluted net loss per share (in thousands, except share and per share amounts): Three Months Ended March 31, 2019 2018 Numerator: Net loss allocated to common stock-basic $ (23,075 ) $ (17,005 ) Net loss allocated to common stock-diluted $ (23,075 ) $ (17,005 ) Denominator: Weighted average number of common stock shares outstanding - basic 61,890,632 53,752,753 Weighted average number of common stock shares outstanding - diluted 61,890,632 53,752,753 Net loss per share - basic: $ (0.37 ) $ (0.32 ) Net loss per share - diluted: $ (0.37 ) $ (0.32 ) The following table shows the total outstanding securities considered anti-dilutive and therefore excluded from the computation of diluted net loss per share (in thousands): Three Months Ended March 31, 2019 2018 Common stock options 7,349 5,173 Incentive awards 127 130 Common stock warrants - 982 7,476 6,285 Recently Adopted Accounting Pronouncements Accounting Standards Update 2016-02 and 2018-11 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The Company adopted this standard on January 1, 2019 using the modified retrospective approach and elected the package of practical expedients permitted under transition guidance, which allowed the Company to carry forward its historical assessments of: 1) whether contracts are or contain leases, 2) lease classification and 3) initial direct costs. The Company did not elect the practical expedient allowing the use-of-hindsight which would require the Company to reassess the lease term of its leases based on all facts and circumstances through the effective date and did not elect the practical expedient pertaining to land easements as this is not applicable to the current contract portfolio. The Company elected the post-transition practical expedient to not separate lease components from nonlease components for all existing lease classes. The Company also elected a policy of not recording leases on its condensed consolidated balance sheets when the leases have a term of 12 months or less and the Company is not reasonably certain to elect an option to purchase the leased asset. The adoption of this standard resulted in the recognition of a ROU asset and lease liabilities of $0.2 million and $2.5 million, respectively, and the derecognition of the deferred rent balance of $2.3 million as of January 1, 2019. The adoption of the standard had no impact on the Company’s condensed consolidated statements of operations and comprehensive loss or to its cash flows from or used in operating, financing, or investing activities on its condensed consolidated statements of cash flows. No cumulative-effect adjustment within accumulated deficit was required to be recorded as a result of adopting this standard. Accounting Standards Update 2018-08 On January 1, 2019 the Company adopted ASU No. 2018-08, Not-For-Profit Entities (Topic 958): Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made (ASU No. 2018-08), which is intended to clarify and improve the scope and the accounting guidance for contributions received and contributions made. The amendments in ASU No. 2018-08 assist entities in (1) evaluating whether transactions should be accounted for as contributions (nonreciprocal transaction) within the scope of Topic 958, Not-for-Profit Entities, or as exchange (reciprocal) transactions subject to other guidance and (2) determining whether a contribution is conditional. This amendment applies to all entities that make or receive grants or contributions. The adoption of this standard did not have a material impact on the Company’s condensed consolidated financial statements. Accounting Standards Update 2018-07 On January 1, 2019, the Company adopted ASU 2018-07, Compensation – Stock Compensation – The adoption of this standard did not have a material impact on the Company’s condensed consolidated financial statements. SEC Securities Act Release No. 33-10532 In August 2018, the SEC adopted amendments to certain disclosure requirements in Securities Act Release No. 33-10532, Disclosure Update and Simplification Recently Issued Accounting Pronouncements In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606. The guidance clarifies that certain transactions between collaborative arrangement participants should be accounted for as revenue under Topic 606 when the collaborative arrangement participant is a customer. For the company, the amendment will be effective January 1, 2020. The Company is evaluating the impact this guidance will have on its consolidated financial statements and related disclosures. Accounting Standards Update 2018-15 Accounting Standards Update 2018-13 In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Accounting Standards Update 2016-13 In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, an amendment which modifies the measurement and recognition of credit losses for most financial assets and certain other instruments. The amendment updates the guidance for measuring and recording credit losses on financial assets measured at amortized cost by replacing the “incurred loss” model with an “expected loss” model. Accordingly, these financial assets will be presented at the net amount expected to be collected. The amendment also requires that credit losses related to available-for-sale debt securities be recorded as an allowance through net income rather than reducing the carrying amount under the current, other-than-temporary-impairment model. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for annual periods after December 15, 2018. The Company is currently evaluating the impact of adoption of this ASU on its condensed consolidated financial statements.

Other Accrued Liabilities

Other Accrued Liabilities	3 Months Ended
	Mar. 31, 2019
Other Accrued Liabilities Current [Abstract]
Other Accrued Liabilities	3. Other Accrued Liabilities O ther accrued liabilities consist of (in thousands): March 31, December 31, 2019 2018 Accrued compensation $ 1,228 $ 2,759 Accrued professional fees and other 1,197 670 Operating lease liability 357 - Deferred rent - 425 Total other accrued liabilities $ 2,782 $ 3,854

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration and License Agreements	4. Collaboration and License Agreements Janssen Pharmaceutical NV and Janssen Pharmaceuticals, Inc. In June 2006, the Company entered into an exclusive, worldwide, royalty-bearing license to 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 particular patents covering the PPARδ Product(s) 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. No amounts were incurred or accrued for this agreement as of and for the three months ended March 31, 2019 and 2018. 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. 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 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 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 had 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). On October 24, 2018, the Company received a notice of Kowa’s intent to terminate the license agreement for the development of arhalofenate. The termination was effective on January 22, 2019. As a result of the termination, the rights licensed to Kowa through the agreement reverted to the Company on the termination date and the Company is no longer eligible to receive additional milestone payments or royalties from Kowa.

Leases

Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	5. Leases The Company has one operating lease pertaining to 17,698 square feet of corporate office space in Newark, California pursuant to a lease agreement which commenced January 16, 2014 and was amended on April 16, 2018. At March 31, 2019 the Company’s lease portfolio had a weighted average remaining term of 4.8 years, with an option to extend for an additional 5 years. The lease requires monthly lease payments that are subject to annual increases throughout the lease term. The optional period has not been considered in the determination of the right-of-use assets or lease liabilities associated with this lease as the Company did not consider it reasonably certain it would exercise the option. The Company cannot determine the implicit rate in its lease, and therefore the Company uses its incremental borrowing rate as the discount rate when measuring operating lease liabilities. The incremental borrowing rate represents an estimate of the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of a lease within a particular currency environment. The Company used an incremental borrowing rate as of the date of adoption for leases that commenced prior to January 1, 2019. The weighted average discount rate for the Company’s lease portfolio is 12.6%. For the three months ended March 31, 2019, the Company incurred $0.1 million of lease costs included in operating expenses in the condensed consolidated statements of income and comprehensive income in relation to its operating lease, a portion of which was variable rent expense and not included within the measurement of the Company’s operating ROU assets and lease liabilities. The variable rent expense consists primarily of the Company’s proportionate share of operating expenses, property taxes, and insurance and is classified as lease expense due to the Company’s election to not separate lease and non-lease components. Rent expense for the three months ended March 31, 2018 was $0.1 million, a portion of which represents immaterial variable rent expense. Supplemental information on the Company’s condensed consolidated balance sheets and statements of cash flow related to leases was as follows (in thousands): March 31, 2019 Balance sheet Operating lease right-of-use assets $ 177 Operating lease liability (Other accrued liabilities) $ 357 Long-term portion of operating lease liability 2,053 Total operating lease liability $ 2,410 Three Months Ended March 31, 2019 Cash flows Cash paid for amounts included in the measurement of lease liabilities $ 157 As of March 31, 2019, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Operating Leases Year ending December 31, 2019 (from April to December) $ 471 2020 647 2021 667 2022 686 2023 707 Thereafter 30 Total undiscounted future minimum lease payments $ 3,208 Less: Imputed interest 798 Total operating lease liability $ 2,410 Less: Current portion of operating lease liability 357 Long-term portion of operating lease liability $ 2,053

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity	6. Stockholders’ Equity On February 1, 2018, pursuant to a On March 8, 2019, pursuant to a shelf registration statement on Form S-3, the Company issued 8,000,000 shares of its common stock at $12.50 per share in an underwritten public offering (referred to as the March 2019 public offering). On March 11, 2019, the underwriters fully exercised their option to purchase additional shares resulting in the issuance of an additional 1,200,000 shares. Net proceeds to the Company from the March 2019 public offering were approximately $107.7 million after deducting underwriting discounts, commissions and other offering expenses.

Stock Plan and Stock-Based Comp

Stock Plan and Stock-Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Plan and Stock-Based Compensation	7. Stock Plan and Stock-Based Compensation Stock Plan In accordance with the provisions of the Company’s 2013 Equity Incentive Plan (2013 Plan), the Board of Directors reduced the automatic increase in the share reserve to 2,378,259 shares, which were automatically available for issuance on January 1, 2019. During the three months ended March 31, 2019, the Company granted options to purchase 1,834,060 shares of its common stock to its employees and directors. As of March 31, 2019, there were 1,855,694 shares available for grant under the 2013 Plan. Stock-Based Compensation Expense Stock-based compensation expense is included in the condensed consolidated statements of operations and comprehensive loss and is as follows (in thousands): Three Months Ended March 31, 2019 2018 Research and development $ 1,112 $ 649 General and administrative 1,230 1,147 Total stock-based compensation expense $ 2,342 $ 1,796

Organization and Description _2

Organization and Description of Business (Policies)	3 Months Ended
	Mar. 31, 2019
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, 2019, the Company incurred a net loss of $23.1 million and used $22.4 million of cash in operations. At March 31, 2019, the Company had an accumulated deficit of $546.1 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, 2019, the Company had cash, cash equivalents and marketable securities totaling $264.8 million which the Company believes is 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 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 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; 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 subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The Company has no unconsolidated subsidiaries or investments accounted for under the equity method. These unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. 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, 2018, which is contained in the Company’s Annual Report on Form 10-K as filed with the SEC on February 28, 2019. The results for the three months ended March 31, 2019 are not necessarily indicative of results to be expected for the entire year ending December 31, 2019 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 the ultimate future outcomes, and management must select an amount that falls within that range of reasonable estimates. Actual results could differ materially from those estimates and assumptions. The Company believes significant judgment can be involved in estimating stock-based compensation, accrued clinical expenses, and the fair value of the Company’s common stock warrants. These estimates form the basis for making judgments about the carrying values of assets and liabilities when these values are not readily apparent from other sources. Estimates are assessed each reporting period and updated to reflect current information and any changes in estimates will be reflected in the period first identified.
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. 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, 2019 Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 113,114 $ - $ - $ 113,114 U.S. commercial paper - 3,481 - 3,481 Total cash equivalents 113,114 3,481 - 116,595 Marketable securities: U.S. and foreign commercial paper - 52,158 - 52,158 U.S. and foreign corporate debt securities - 38,318 - 38,318 Asset-backed securities - 25,400 - 25,400 U.S. treasury securities - 23,306 - 23,306 Total short-term investments - 139,182 - 139,182 Total assets measured at fair value $ 113,114 $ 142,663 $ - $ 255,777 As of December 31, 2018 Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 39,481 $ - $ - $ 39,481 U.S. and foreign commercial paper - 6,469 - 6,469 Total cash equivalents 39,481 6,469 - 45,950 Marketable securities: U.S. and foreign commercial paper - 51,627 - 51,627 U.S. and foreign corporate debt securities - 34,634 - 34,634 Asset-backed securities - 25,472 - 25,472 U.S. treasury securities - 17,936 - 17,936 Total short-term investments - 129,669 - 129,669 Total assets measured at fair value $ 39,481 $ 136,138 $ - $ 175,619 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. Historically, the Company held 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 were accounted for as liabilities until either they were exercised or expired in September 2018. The Company used a binomial option pricing model to value its warrant liabilities prior to September 2017. 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, included the expected timing, probability and valuation impact of certain potential strategic events. 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. The following table sets forth a summary of the changes in the fair value of the Company’s liabilities measured using Level 3 inputs (in thousands): For the Three Months Ended March 31, 2019 2018 Balance, beginning of period $ - $ 6,091 Change in fair value - 4,654 Settlement of financial instruments - (3,097 ) Balance, end of period $ - $ 7,648
Cash, Cash Equivalents and Marketable Securities	Cash, 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, 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 or equal to 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 condensed consolidated statements of operations and comprehensive loss. Unrealized holding gains and losses are reported in accumulated other comprehensive loss in the condensed consolidated 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 of the Company’s available for sale marketable securities (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of March 31, 2019: U.S. and foreign commercial paper $ 52,158 $ - $ - $ 52,158 U.S. and foreign corporate debt securities 38,289 29 - 38,318 Asset-backed securities 25,395 6 (1 ) 25,400 U.S. treasury securities 23,295 11 - 23,306 $ 139,137 $ 46 $ (1 ) $ 139,182 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of December 31, 2018: U.S. and foreign commercial paper $ 51,627 $ - $ - $ 51,627 U.S. and foreign corporate debt securities 34,668 - (34 ) 34,634 Asset-backed securities 25,494 - (22 ) 25,472 U.S. treasury securities 17,938 - (2 ) 17,936 $ 129,727 $ - $ (58 ) $ 129,669
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 condensed consolidated 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 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.
Leases	Leases The Company has one lease, a non-cancelable operating lease agreement for its corporate offices. Prior to January 1, 2019, the Company recognized related rent expense on a straight-line basis over the term of the lease. Incentives granted under the Company’s facilities lease, including allowances for leasehold improvements and rent holidays, were recognized as reductions to rental expense on a straight-line basis over the term of the lease. Deferred rent consisted of the difference between cash payments and the rent expense recognized. Subsequent to the adoption of the new leasing standard on January 1, 2019, the Company recognizes a lease asset for its right to use the underlying asset and a lease liability for the corresponding lease obligation. The Company determines whether an arrangement is or contains a lease at contract inception. Operating leases are included in operating lease right-of-use assets, other accrued liabilities, and long-term portion of operating lease liabilities in our condensed consolidated balance sheet at March 31, 2019. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the net present value of lease payments, the Company uses its incremental borrowing rate based on the information available at the lease commencement date. The incremental borrowing rate represents the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of a lease. The Company considers a lease term to be the noncancelable period that it has the right to use the underlying asset, including any periods where it is reasonably assured the Company will exercise the option to extend the contract. Periods covered by an option to extend are included in the lease term if the lessor controls the exercise of that option. The operating lease right-of-use assets also include any lease payments made and exclude lease incentives. Lease expense is recognized on a straight-line basis over the expected lease term. The Company has elected to not separate lease and non-lease components for its leased assets and accounts for all lease and non-lease components of its agreements as a single lease component.
Common Stock Warrant Liabilities	Common Stock Warrant Liability Historically, the Company’s outstanding common stock warrants issued in connection with certain equity and debt financings that occurred in 2013 through 2015 were classified as liabilities in the accompanying condensed consolidated balance sheets because of certain contractual terms that preclude equity classification. As of September 30, 2018, all outstanding warrants related to these financings had been exercised or had expired. Upon expiration, the remaining fair value of the liability was extinguished and credited to other income (expense), net in the Company’s condensed consolidated statement of operations. Prior to expiration, the Company estimated the fair value of common stock warrants at each reporting period until the exercise of the warrants, at which time the liability was revalued and reclassified to stockholders’ equity. The determination of fair value of these common stock warrants required 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.
Research and Development Expenses	Research and Development Expenses Research and development expenses consist of costs incurred in identifying, developing, and testing product candidates. These expenses consist primarily of costs for research and development personnel, including related stock-based compensation; contract research organizations (CRO) and other third parties that assist in managing, monitoring, and analyzing clinical trials; investigator and site fees; laboratory services; consultants; contract manufacturing services; non-clinical studies, including materials; and allocated expenses, such as depreciation of assets, and facilities and information technology that support research and development activities. Research and development costs are expensed as incurred, including expenses that may or may not be reimbursed under research and development funding arrangements. Payments made prior to the receipt of goods or services to be used in research and development are recorded as prepaid assets until the goods are received or services are rendered. Such payments are evaluated for current or long term classification based on when they will be realized. The Company records expenses related to clinical studies and manufacturing development activities based on its estimates of the services received and efforts expended pursuant to contracts with multiple CROs and manufacturing vendors that conduct and manage these activities on its behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract, and may result in uneven payment flows. There may be instances in which payments made to the Company’s vendors will exceed the level of services provided and result in a prepayment of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of subjects and the completion of clinical trial milestones. In amortizing or accruing service fees, the Company estimates the time period over which services will be performed, enrollment of subjects, number of sites activated and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the Company’s estimate, the Company will adjust the accrued or prepaid expense balance accordingly. To date, there have been no material differences from the Company’s estimates to the amounts actually incurred.
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 options 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 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 has historically been subject to remeasurement at each reporting date as the underlying equity instruments vest and was recognized as an expense over the period during which services are received. Upon the adoption of ASU 2018-07, Compensation – Stock Compensation
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per share of common stock is based on the weighted average number of shares of common stock outstanding equivalents during the period. Diluted net loss per share of common stock is calculated as the weighted average number of shares of common stock outstanding adjusted to include the assumed exercises of stock options and 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 and actual exercise or expiration of such securities are dilutive to earnings (net loss) per share for the period, adjustments to net income or net loss used in the calculation are required to remove the change in fair value of the 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 were excluded from the calculation of diluted net loss per share because their effects were antidilutive. The following table sets forth the computation of basic and diluted net loss per share (in thousands, except share and per share amounts): Three Months Ended March 31, 2019 2018 Numerator: Net loss allocated to common stock-basic $ (23,075 ) $ (17,005 ) Net loss allocated to common stock-diluted $ (23,075 ) $ (17,005 ) Denominator: Weighted average number of common stock shares outstanding - basic 61,890,632 53,752,753 Weighted average number of common stock shares outstanding - diluted 61,890,632 53,752,753 Net loss per share - basic: $ (0.37 ) $ (0.32 ) Net loss per share - diluted: $ (0.37 ) $ (0.32 ) The following table shows the total outstanding securities considered anti-dilutive and therefore excluded from the computation of diluted net loss per share (in thousands): Three Months Ended March 31, 2019 2018 Common stock options 7,349 5,173 Incentive awards 127 130 Common stock warrants - 982 7,476 6,285
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements Accounting Standards Update 2016-02 and 2018-11 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The Company adopted this standard on January 1, 2019 using the modified retrospective approach and elected the package of practical expedients permitted under transition guidance, which allowed the Company to carry forward its historical assessments of: 1) whether contracts are or contain leases, 2) lease classification and 3) initial direct costs. The Company did not elect the practical expedient allowing the use-of-hindsight which would require the Company to reassess the lease term of its leases based on all facts and circumstances through the effective date and did not elect the practical expedient pertaining to land easements as this is not applicable to the current contract portfolio. The Company elected the post-transition practical expedient to not separate lease components from nonlease components for all existing lease classes. The Company also elected a policy of not recording leases on its condensed consolidated balance sheets when the leases have a term of 12 months or less and the Company is not reasonably certain to elect an option to purchase the leased asset. The adoption of this standard resulted in the recognition of a ROU asset and lease liabilities of $0.2 million and $2.5 million, respectively, and the derecognition of the deferred rent balance of $2.3 million as of January 1, 2019. The adoption of the standard had no impact on the Company’s condensed consolidated statements of operations and comprehensive loss or to its cash flows from or used in operating, financing, or investing activities on its condensed consolidated statements of cash flows. No cumulative-effect adjustment within accumulated deficit was required to be recorded as a result of adopting this standard. Accounting Standards Update 2018-08 On January 1, 2019 the Company adopted ASU No. 2018-08, Not-For-Profit Entities (Topic 958): Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made (ASU No. 2018-08), which is intended to clarify and improve the scope and the accounting guidance for contributions received and contributions made. The amendments in ASU No. 2018-08 assist entities in (1) evaluating whether transactions should be accounted for as contributions (nonreciprocal transaction) within the scope of Topic 958, Not-for-Profit Entities, or as exchange (reciprocal) transactions subject to other guidance and (2) determining whether a contribution is conditional. This amendment applies to all entities that make or receive grants or contributions. The adoption of this standard did not have a material impact on the Company’s condensed consolidated financial statements. Accounting Standards Update 2018-07 On January 1, 2019, the Company adopted ASU 2018-07, Compensation – Stock Compensation – The adoption of this standard did not have a material impact on the Company’s condensed consolidated financial statements. SEC Securities Act Release No. 33-10532 In August 2018, the SEC adopted amendments to certain disclosure requirements in Securities Act Release No. 33-10532, Disclosure Update and Simplification Recently Issued Accounting Pronouncements In November 2018, the FASB issued ASU 2018-18, Collaborative Arrangements (Topic 808): Clarifying the Interaction between Topic 808 and Topic 606. The guidance clarifies that certain transactions between collaborative arrangement participants should be accounted for as revenue under Topic 606 when the collaborative arrangement participant is a customer. For the company, the amendment will be effective January 1, 2020. The Company is evaluating the impact this guidance will have on its consolidated financial statements and related disclosures. Accounting Standards Update 2018-15 Accounting Standards Update 2018-13 In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Accounting Standards Update 2016-13 In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, an amendment which modifies the measurement and recognition of credit losses for most financial assets and certain other instruments. The amendment updates the guidance for measuring and recording credit losses on financial assets measured at amortized cost by replacing the “incurred loss” model with an “expected loss” model. Accordingly, these financial assets will be presented at the net amount expected to be collected. The amendment also requires that credit losses related to available-for-sale debt securities be recorded as an allowance through net income rather than reducing the carrying amount under the current, other-than-temporary-impairment model. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted for annual periods after December 15, 2018. The Company is currently evaluating the impact of adoption of this ASU on its condensed consolidated financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2019
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, 2019 Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 113,114 $ - $ - $ 113,114 U.S. commercial paper - 3,481 - 3,481 Total cash equivalents 113,114 3,481 - 116,595 Marketable securities: U.S. and foreign commercial paper - 52,158 - 52,158 U.S. and foreign corporate debt securities - 38,318 - 38,318 Asset-backed securities - 25,400 - 25,400 U.S. treasury securities - 23,306 - 23,306 Total short-term investments - 139,182 - 139,182 Total assets measured at fair value $ 113,114 $ 142,663 $ - $ 255,777 As of December 31, 2018 Level 1 Level 2 Level 3 Fair Value Cash equivalents: Money market funds $ 39,481 $ - $ - $ 39,481 U.S. and foreign commercial paper - 6,469 - 6,469 Total cash equivalents 39,481 6,469 - 45,950 Marketable securities: U.S. and foreign commercial paper - 51,627 - 51,627 U.S. and foreign corporate debt securities - 34,634 - 34,634 Asset-backed securities - 25,472 - 25,472 U.S. treasury securities - 17,936 - 17,936 Total short-term investments - 129,669 - 129,669 Total assets measured at fair value $ 39,481 $ 136,138 $ - $ 175,619
Schedule of Changes in Fair Value of Liabilities	The following table sets forth a summary of the changes in the fair value of the Company’s liabilities measured using Level 3 inputs (in thousands): For the Three Months Ended March 31, 2019 2018 Balance, beginning of period $ - $ 6,091 Change in fair value - 4,654 Settlement of financial instruments - (3,097 ) Balance, end of period $ - $ 7,648
Schedule of Amortized Cost, Unrealized Gain and Loss, and Fair Value of Available for Sale Marketable Securities	The following tables summarize amortized cost, unrealized gain and loss, and fair value of the Company’s available for sale marketable securities (in thousands): Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of March 31, 2019: U.S. and foreign commercial paper $ 52,158 $ - $ - $ 52,158 U.S. and foreign corporate debt securities 38,289 29 - 38,318 Asset-backed securities 25,395 6 (1 ) 25,400 U.S. treasury securities 23,295 11 - 23,306 $ 139,137 $ 46 $ (1 ) $ 139,182 Gross Gross Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value As of December 31, 2018: U.S. and foreign commercial paper $ 51,627 $ - $ - $ 51,627 U.S. and foreign corporate debt securities 34,668 - (34 ) 34,634 Asset-backed securities 25,494 - (22 ) 25,472 U.S. treasury securities 17,938 - (2 ) 17,936 $ 129,727 $ - $ (58 ) $ 129,669
Computation of Basic and Diluted Net Loss per Share	The following table sets forth the computation of basic and diluted net loss per share (in thousands, except share and per share amounts): Three Months Ended March 31, 2019 2018 Numerator: Net loss allocated to common stock-basic $ (23,075 ) $ (17,005 ) Net loss allocated to common stock-diluted $ (23,075 ) $ (17,005 ) Denominator: Weighted average number of common stock shares outstanding - basic 61,890,632 53,752,753 Weighted average number of common stock shares outstanding - diluted 61,890,632 53,752,753 Net loss per share - basic: $ (0.37 ) $ (0.32 ) Net loss per share - diluted: $ (0.37 ) $ (0.32 )
Anti-Dilutive Securities Excluded from the Computation of Diluted Net Loss per Share	The following table shows the total outstanding securities considered anti-dilutive and therefore excluded from the computation of diluted net loss per share (in thousands): Three Months Ended March 31, 2019 2018 Common stock options 7,349 5,173 Incentive awards 127 130 Common stock warrants - 982 7,476 6,285

Other Accrued Liabilities (Tabl

Other Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
Other Accrued Liabilities Current [Abstract]
Summary of Other Accrued Liabilities	O ther accrued liabilities consist of (in thousands): March 31, December 31, 2019 2018 Accrued compensation $ 1,228 $ 2,759 Accrued professional fees and other 1,197 670 Operating lease liability 357 - Deferred rent - 425 Total other accrued liabilities $ 2,782 $ 3,854

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Schedule of Information Related to Leases	Supplemental information on the Company’s condensed consolidated balance sheets and statements of cash flow related to leases was as follows (in thousands): March 31, 2019 Balance sheet Operating lease right-of-use assets $ 177 Operating lease liability (Other accrued liabilities) $ 357 Long-term portion of operating lease liability 2,053 Total operating lease liability $ 2,410 Three Months Ended March 31, 2019 Cash flows Cash paid for amounts included in the measurement of lease liabilities $ 157
Summary of Maturities of Operating Lease Liabilities	As of March 31, 2019, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Operating Leases Year ending December 31, 2019 (from April to December) $ 471 2020 647 2021 667 2022 686 2023 707 Thereafter 30 Total undiscounted future minimum lease payments $ 3,208 Less: Imputed interest 798 Total operating lease liability $ 2,410 Less: Current portion of operating lease liability 357 Long-term portion of operating lease liability $ 2,053

Stock Plan and Stock-Based Co_2

Stock Plan and Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-Based Compensation Expense	Stock-based compensation expense is included in the condensed consolidated statements of operations and comprehensive loss and is as follows (in thousands): Three Months Ended March 31, 2019 2018 Research and development $ 1,112 $ 649 General and administrative 1,230 1,147 Total stock-based compensation expense $ 2,342 $ 1,796

Organization and Description _3

Organization and Description of Business - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)Segment	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segments | Segment	1
Net loss	$ (23,075)	$ (17,005)
Cash flows from operating activities	(22,394)	$ (6,441)
Accumulated deficit	(546,139)		$ (523,064)
Cash and cash equivalents and marketable securities	$ 264,800

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 255,777	$ 175,619
Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	116,595	45,950
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	113,114	39,481
Cash Equivalents [Member] | U.S. and Foreign Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	3,481	6,469
Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	139,182	129,669
Short-term Investments [Member] | U.S. and Foreign Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	52,158	51,627
Short-term Investments [Member] | U.S. and Foreign Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	38,318	34,634
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	25,400	25,472
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	23,306	17,936
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	113,114	39,481
Level 1 [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	113,114	39,481
Level 1 [Member] | Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	113,114	39,481
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	142,663	136,138
Level 2 [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	3,481	6,469
Level 2 [Member] | Cash Equivalents [Member] | U.S. and Foreign Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	3,481	6,469
Level 2 [Member] | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	139,182	129,669
Level 2 [Member] | Short-term Investments [Member] | U.S. and Foreign Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	52,158	51,627
Level 2 [Member] | Short-term Investments [Member] | U.S. and Foreign Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	38,318	34,634
Level 2 [Member] | 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	25,400	25,472
Level 2 [Member] | 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	$ 23,306	$ 17,936

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	Jan. 01, 2019USD ($)	Mar. 31, 2019USD ($)Facility
Product Information [Line Items]
Warrants exercise or expiration period		Sep. 30, 2018
Cash and cash equivalents, maturity description		90 days or less
Number of leased facilities | Facility		1
Lessee, operating lease, description		The Company also elected a policy of not recording leases on its condensed consolidated balance sheets when the leases have a term of 12 months or less and the Company is not reasonably certain to elect an option to purchase the leased asset
ROU assets		$ 177
Lease liabilities		$ 2,410
ASU 2018-11 [Member]
Product Information [Line Items]
ROU assets	$ 200
Lease liabilities	2,500
Derecognition of the deferred rent	$ 2,300
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 Accoun_5

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

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Amortized Cost, Unrealized Gain and Loss, and Fair Value of Available for Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 139,137	$ 129,727
Gross Unrealized Gains	46	0
Gross Unrealized Losses	(1)	(58)
Estimated Fair Value	139,182	129,669
U.S. and Foreign Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	52,158	51,627
Estimated Fair Value	52,158	51,627
U.S. and Foreign Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	38,289	34,668
Gross Unrealized Gains	29
Gross Unrealized Losses		(34)
Estimated Fair Value	38,318	34,634
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	25,395	25,494
Gross Unrealized Gains	6	0
Gross Unrealized Losses	(1)	(22)
Estimated Fair Value	25,400	25,472
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,295	17,938
Gross Unrealized Gains	11	0
Gross Unrealized Losses		(2)
Estimated Fair Value	$ 23,306	$ 17,936

Summary of Significant Accoun_7

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, 2019	Mar. 31, 2018
Numerator:
Net loss allocated to common stock-basic	$ (23,075)	$ (17,005)
Net loss allocated to common stock-diluted	$ (23,075)	$ (17,005)
Denominator:
Weighted average number of common stock shares outstanding - basic	61,890,632	53,752,753
Weighted average number of common stock shares outstanding - diluted	61,890,632	53,752,753
Net loss per share - basic:	$ (0.37)	$ (0.32)
Net loss per share - diluted:	$ (0.37)	$ (0.32)

Summary of Significant Accoun_8

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, 2019	Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share	7,476	6,285
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	7,349	5,173
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	127	130
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

Other Accrued Liabilities - Sum

Other Accrued Liabilities - Summary of Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Other Accrued Liabilities Current [Abstract]
Accrued compensation	$ 1,228	$ 2,759
Accrued professional fees and other	1,197	670
Operating lease liability	357
Deferred rent		425
Total other accrued liabilities	$ 2,782	$ 3,854

Collaboration and License Agr_2

Collaboration and License Agreements - Additional Information (Detail)	1 Months Ended		3 Months Ended
	Jun. 30, 2010Agreement	Jun. 30, 2006	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)
Janssen Pharmaceutical NV [Member]
gaap:Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty payment			$ 0	$ 0
Accrued royalties			0	0
Janssen Pharmaceutical NV [Member] | Maximum [Member]
gaap:Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales		8.00%
Janssen Pharmaceuticals, Inc. [Member]
gaap:Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of development and license agreements | Agreement	2
DiaTex, Inc. [Member]
gaap:Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty payment			0	0
Development payment			$ 0	$ 0

Leases - Additional Information

Leases - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2019USD ($)ft²Facility	Mar. 31, 2018USD ($)
Lessee Lease Description [Line Items]
Weighted average remaining lease term	4 years 9 months 18 days
Lease, option to extend	option to extend for an additional 5 years
Weighted average lease discount rate	12.60%
Rent expenses		$ 0.1
Operating Expense [Member]
Lessee Lease Description [Line Items]
Lease costs	$ 0.1
Lease Facility [Member]
Lessee Lease Description [Line Items]
Number of leased facilities | Facility	1
Area of office space | ft²	17,698
Lease start date	Jan. 16, 2014

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Balance sheet
Operating lease right-of-use assets	$ 177
Operating lease liability (Other accrued liabilities)	357
Long-term portion of operating lease liability	2,053
Total operating lease liability	2,410
Cash flows
Cash paid for amounts included in the measurement of lease liabilities	$ 157

Leases - Summary of Maturities

Leases - Summary of Maturities of Operating Lease Liabilities (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Leases [Abstract]
2019 (from April to December)	$ 471
2020	647
2021	667
2022	686
2023	707
Thereafter	30
Total undiscounted future minimum lease payments	3,208
Less: Imputed interest	798
Lease liabilities	2,410
Less: Current portion of operating lease liability	357
Long-term portion of operating lease liability	$ 2,053

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Mar. 06, 2019	Feb. 01, 2018	Mar. 31, 2019	Mar. 11, 2019	Dec. 31, 2018
Equity [Abstract]
Common stock, shares issued	8,000,000	13,340,000	68,694,043	1,200,000	59,456,493
Common stock offering price	$ 12.50	$ 10.80
Net proceeds from public offering	$ 107.7	$ 135.5

Stock Plan and Stock-Based Co_3

Stock Plan and Stock-Based Compensation - Additional Information (Detail) - 2013 Equity Incentive Plan [Member] - shares	Jan. 01, 2019	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in shares reserved for issuance	2,378,259
Shares available for grant		1,855,694
Employees, Directors and Consultant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of option granted to employees		1,834,060

Stock Plan and Stock-Based Co_4

Stock Plan and Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 2,342	$ 1,796
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,112	649
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 1,230	$ 1,147