Cymabay Therapeutics (CBAY) 10-K 25 Mar 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 28, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	CBAY
Entity Registrant Name	CYMABAY THERAPEUTICS, INC.
Entity Central Index Key	0001042074
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		68,946,092
Entity Shell Company	false
Entity File Number	001-36500
Entity Tax Identification Number	94-3103561
Entity Address, Address Line One	7575 Gateway Blvd
Entity Address, Address Line Two	Suite 110
Entity Address, City or Town	Newark
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94560
City Area Code	510
Local Phone Number	293-8800
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
Entity Public Float			$ 238,474,701
ICFR Auditor Attestation Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 28,193	$ 24,869
Marketable securities	118,130	166,076
Accrued interest receivable	277	687
Prepaid research and development expenses	2,221	9,910
Other prepaid expenses and current assets	2,764	1,381
Total current assets	151,585	202,923
Property and equipment, net	1,761	2,409
Operating lease right-of-use asset	272	235
Other assets	207	160
Total assets	153,825	205,727
Current liabilities:
Accounts payable	231	2,503
Accrued research and development expenses	4,698	9,218
Accrued restructuring	18	3,193
Other accrued liabilities	4,910	2,722
Total current liabilities	9,857	17,636
Long-term portion of operating lease liability	1,262	1,743
Commitments and contingencies (Note 6)
Total liabilities	11,119	19,379
Stockholders' equity:
Preferred stock, $0.0001 par value: 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value: 200,000,000 shares authorized; 68,946,092 and 68,882,459 shares issued and outstanding as of December 31, 2020 and December 31, 2019, respectively	7	7
Additional paid-in capital	819,549	812,133
Accumulated other comprehensive income	8	80
Accumulated deficit	(676,858)	(625,872)
Total stockholders' equity	142,706	186,348
Total liabilities and stockholders' equity	$ 153,825	$ 205,727

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
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	200,000,000	100,000,000
Common stock, shares issued	68,946,092	68,882,459
Common stock, shares outstanding	68,946,092	68,882,459

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating expenses:
Research and development	$ 35,882	$ 83,837
General and administrative	17,425	19,238
Restructuring (benefit) charges	(705)	5,075
Total operating expenses	52,602	108,150
Loss from operations	(52,602)	(108,150)
Other income:
Interest income	1,616	5,342
Total other income	1,616	5,342
Net loss	(50,986)	(102,808)
Other comprehensive (loss) income:
Unrealized (loss) gain on marketable securities	(72)	138
Total other comprehensive (loss) income	(72)	138
Comprehensive loss	$ (51,058)	$ (102,670)
Basic and diluted net loss per common share	$ (0.74)	$ (1.53)
Weighted average common shares outstanding used to calculate basic and diluted net loss per common share	68,893,127	67,033,046

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
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, net of $7,254 issuance costs	386		386
Issuance of common stock, net of $7,254 issuance costs (Shares)		225,966
Stock-based compensation expense	10,468		10,468
Issuance costs of common stock, net of issuance costs, value	107,746	$ 1	107,745
Issuance of common stock, (in shares)		9,200,000
Net loss	(102,808)				(102,808)
Net unrealized gain (loss) on marketable securities	138			138
Balance at end of period at Dec. 31, 2019	186,348	$ 7	812,133	80	(625,872)
Balance at end of period (in shares) at Dec. 31, 2019		68,882,459
Issuance of common stock, net of $7,254 issuance costs	$ 92		92
Issuance of common stock, net of $7,254 issuance costs (Shares)	63,633	63,633
Stock-based compensation expense	$ 7,324		7,324
Net loss	(50,986)				(50,986)
Net unrealized gain (loss) on marketable securities	(72)			(72)
Balance at end of period at Dec. 31, 2020	$ 142,706	$ 7	$ 819,549	$ 8	$ (676,858)
Balance at end of period (in shares) at Dec. 31, 2020		68,946,092

Consolidated Statement of Sto_2

Consolidated Statement of Stockholders' Equity (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Statement of Stockholders' Equity [Abstract]
Stock issuance cost	$ 7,254

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net loss	$ (50,986)	$ (102,808)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	632	572
Stock-based compensation expense	7,135	9,558
Accelerated vesting of stock-based compensation due to restructuring	189	910
Net accretion and amortization of investments in marketable securities	(104)	(2,237)
Changes in assets and liabilities:
Interest receivable and other current assets	(361)	(383)
Prepaid expenses	7,077	(8,697)
Other assets	(47)	2,120
Accounts payable	(2,272)	530
Accrued restructuring charges	(3,175)	3,193
Accrued liabilities	(2,813)	(669)
Net cash used in operating activities	(44,725)	(97,911)
Investing activities
Purchases of property and equipment	(21)	(315)
Purchases of marketable securities	(176,300)	(290,893)
Proceeds from maturities of marketable securities	224,278	252,881
Proceeds from sale of marketable securities		3,980
Net cash provided by (used in) investing activities	47,957	(34,347)
Financing activities
Proceeds from issuance of common stock, net of issuance costs		107,746
Proceeds from issuance of common stock pursuant to equity award plans	92	386
Cash provided by financing activities	92	108,132
Net increase (decrease) in cash and cash equivalents	3,324	(24,126)
Cash and cash equivalents at beginning of period	24,869	48,995
Cash and cash equivalents at end of period	28,193	24,869
Supplemental disclosures
Cash paid for amounts included in the measurement of lease liabilities	$ 647	628
Operating lease right-of-use assets obtained in exchange for lease liabilities		$ 152

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2020
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. Seladelpar has primarily been under development for the treatment of liver diseases including 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 year ended December 31, 2020, the Company incurred a net loss of $51.0 Historically, the Company has incurred substantial research and development expenses in the course of studying 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. Generally, the Company’s ability to achieve profitability is dependent on its ability to successfully develop, acquire or in-license As of December 31, 2020, the Company had cash, cash equivalents and marketable securities totaling $146.3 As the Company continues to advance its clinical studies of seladelpar, cash is considered sufficient to fund the Company’s operating plan into mid-2022. The Company has historically obtained, and expects to obtain in the future, additional financing to fund its business strategy through: future equity offerings; debt financing; one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights of the Company’s 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. Market volatility resulting from the global novel coronavirus disease (COVID-19) pandemic or other factors could also adversely impact our ability to access capital when and as needed. Failure to raise sufficient capital when needed could require us to significantly delay, scale back or discontinue one or more of our product development programs or commercialization efforts or other aspects of our business plans, and our operating results and financial condition would be adversely affected. In July 2020, the Company filed a $200.0 million registration statement on Form S-3 at-the-market

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Use of Estimates The accompanying consolidated financial statements are comprised of the accounts 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 consolidated statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP), which requires management to make informed estimates and assumptions that impact the amounts and disclosures reported in the consolidated financial statements and accompanying notes. Accounting estimates and assumptions are inherently uncertain. 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. 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 generally 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, accrued interest receivables, prepaid expenses, other current assets, accounts payable, and accrued expenses. 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, receivables, prepaid expenses, other current assets, accounts payable, and accrued expenses 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 — Q Level 2 — Level 3 — 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 December 31, 2020 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 22,415 $ — $ — $ 22,415 Total cash equivalents 22,415 — — 22,415 Marketable securities: U.S. and foreign commercial paper — 38,561 — 38,561 U.S. and foreign corporate debt securities — 29,189 — 29,189 Asset-backed securities — 7,885 — 7,885 U.S. agency securities — 23,994 — 23,994 U.S. treasury securities — 15,499 — 15,499 Supranational debt securities — 3,002 — 3,002 Total marketable securities — 118,130 — 118,130 Total assets measured at fair value $ 22,415 $ 118,130 $ — $ 140,545 As of December 31, 2019 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 18,597 $ — $ — $ 18,597 Total cash equivalents 18,597 — — 18,597 Marketable securities: U.S. and foreign commercial paper — 51,102 — 51,102 U.S. and foreign corporate debt securities — 56,729 — 56,729 Asset-backed securities — 39,788 — 39,788 U.S. treasury securities — 18,457 — 18,457 Total marketable securities — 166,076 — 166,076 Total assets measured at fair value $ 18,597 $ 166,076 $ — $ 184,673 The Company estimates the fair value of its money market funds, corporate debt, asset backed securities, commercial paper U.S. treasury and agency securities and supranational debt 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. See Note 3 for further discussion regarding the carrying value of the Company’s financial instruments. Cash, Cash Equivalents, and Marketable Securities The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist of deposits with commercial banks in checking, interest-bearing, and money market funds. The Company invests excess cash in marketable securities with high credit ratings that are classified in Level 1 or Level 2 of the fair value hierarchy. These securities consist primarily of corporate debt, commercial paper, asset-backed securities, U.S. treasury and agency securities and supranational debt securities and are classified as “available-for-sale.” The Company considers marketable securities as short-term investments if the maturity date is less than 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 consolidated statements of operations and comprehensive loss. Unrealized holding gains and losses are reported in accumulated other comprehensive loss in the 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. Concentration of Credit Risk Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to a concentration of credit risk to the extent of the fair value recorded on 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 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. Property and Equipment Property and equipment are recorded at cost, less accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method, and the costs are amortized over the estimated useful lives of the respective assets, which are generally three to seven years. Leasehold improvements are amortized over the shorter of the useful lives or the non-cancelable Long-Lived Assets The Company reviews the carrying value long-lived assets, including right-of-use income in the period that includes the enactment date. A valuation allowance is recorded when it is more likely than not that all or part of a deferred tax asset will not be realized. When the Company establishes or reduces the valuation allowance related to the deferred tax assets, the provision for income taxes will increase or decrease, respectively, in the period such determination is made. The accounting guidance for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination based on the technical merits of the position. The Company is required to file federal and state income tax returns in the United States. The preparation of these income tax returns requires the Company to interpret the applicable tax laws and regulations in effect that could affect the amount of tax paid to these jurisdictions. The Company records interest related to income tax reserves, if any, as interest expense, and any penalties would be recorded as other expense in the consolidated statements of operations and comprehensive loss. In March 2020, the Families First Coronavirus Response Act (FFCR Act) and the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) were each enacted in response to the COVID-19 In June 2020, Assembly Bill 85 (A.B. 85) was signed into California law. A.B. 85 provides for a three-year suspension of the use of net operating losses for medium and large businesses and a three-year cap on the use of business incentive tax credits to offset no more than $5.0 million of tax per year. A.B. 85 suspends the use of net operating losses for taxable years 2020, 2021 and 2022 for certain taxpayers with taxable income of $1.0 million or more. The carryover period for any net operating losses that are suspended under this provision will be extended. A.B. 85 also requires that business incentive tax credits including carryovers may not reduce the applicable tax by more than $5.0 million for taxable years 2020, 2021 and 2022. In December 2020, the Consolidated Appropriations Act, 2021 (CAA) was signed into law. The CAA included additional funding through tax credits as part of its economic package for 2021. The FFCR Act, CARES Act, A.B. 85 and CAA did not have a material impact on the Company’s consolidated financial statements; however, the Company continues to examine the impacts the FFCR Act, CARES Act, A.B. 85 and CAA may have on its business, results of operations, financial condition and liquidity. Comprehensive Loss Comprehensive loss includes net loss and net unrealized gains and losses on marketable securities, which are presented in a single continuous statement. Other comprehensive (loss) gain is also disclosed in the consolidated balance sheets and statements of stockholders’ equity in accumulated other comprehensive income (loss), and is stated net of related tax effects, if any. Net Loss Per Common Share Basic net loss per share of common stock is based on the weighted average number of shares of common stock outstanding equivalents during the period. Diluted net loss per share of common stock is calculated as the weighted average number of shares of common stock outstanding adjusted to include the assumed exercises of stock options, if dilutive. In all periods presented, the Company’s outstanding stock options were excluded from the calculation of net loss per share because the effect would be antidilutive. The following table sets forth the computation of basic and diluted net loss per share (in thousands, except share and per share amounts): Year Ended December 31, 2020 2019 Numerator: Net loss $ (50,986 ) $ (102,808 ) Denominator: Weighted average number of common stock shares outstanding 68,893,127 67,033,046 Net loss per share $ (0.74 ) $ (1.53 ) 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): Year Ended December 31, 2020 2019 Common stock options 8,812 6,727 Incentive awards 101 101 Total 8,913 6,828 Recently Adopted Accounting Pronouncements ASU 2018-18 In November 2018, the FASB issued ASU 2018-18, Clarifying the Interaction between Topic 808 and Topic 606 ASU 2018-15 In August 2018, the FASB issued ASU No. 2018-15, Intangibles Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract internal-use ASU 2018-13 In August 2018, the FASB issued ASU 2018-13, ( ): Disclosure Framework — C the reporting period and disclosing the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The amendment became effective for the Company on January 1, 2020. The adoption of this standard did not have a material impact on its consolidated financial statements. Recently Issued Accounting Pronouncements ASU 2016-13 In June 2016, the FASB issued ASU No. 2016-13, s — C Measurement of Credit Losses on Financial Instruments available-for-sale No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842) ASU 2019-12 In December 2019, the FASB issued ASU 2019-12, step-up Leases The Company has one lease, a non-cancelable operating lease agreement for its corporate office. 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 consolidated balance sheets at December 31, 2020 and 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. The Company does not record leases on our consolidated balance sheets when a lease has a term of one year or less. 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 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. 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. Restructuring Charges The Company recognizes restructuring charges related to reorganization plans that have been committed to by management and when liabilities have been incurred. In connection with these activities, the Company records one-time One-time The recognition of restructuring charges requires the Company to make certain judgments and estimates regarding the nature, timing and amount of costs associated with the planned reorganization plan. To the extent the Company’s actual results differ from its estimates and assumptions, the Company may be required to revise the estimates of future accrued restructuring liabilities, requiring the recognition of additional restructuring charges or the reduction of accrued restructuring liabilities already recognized. Such changes to previously estimated amounts may be material to the consolidated financial statements. Changes in the estimates of the restructuring charges are recorded in the period the change is determined. At the end of each reporting period, the Company evaluates the remaining accrued restructuring balances to ensure that no excess accruals are retained, and the utilization of the provisions are for their intended purpose in accordance with developed restructuring plans. Stock-Based Compensation 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 with service conditions and forfeitures are accounted for as they occur. 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. If actual results are not consistent with the Company’s assumptions 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. Income Taxes The Company utilizes the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between the financial reporting and the tax bases of assets and liabilities and are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Marketable Securities	3. Marketable Securities Marketable available-for-sale securities consist of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of December 31, 2020: Cash equivalents: Money market funds $ 22,415 $ — $ — $ 22,415 Total cash equivalents 22,415 — — 22,415 Short-term investments: U.S. and foreign commercial paper 38,561 — — 38,561 U.S. and foreign corporate debt securities 29,186 7 (4 ) 29,189 Asset-backed securities 7,883 2 — 7,885 U.S. treasury securities 23,991 3 — 23,994 U.S. agency securities 15,498 1 — 15,499 Supranational debt securities 3,003 — (1 ) 3,002 Total short-term investments 118,122 13 (5 ) 118,130 Total marketable securities 140,537 13 (5 ) 140,545 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of December 31, 2019: Cash equivalents: Money market funds $ 18,597 $ — $ — $ 18,597 Total cash equivalents 18,597 — — 18,597 Short-term investments: U.S. and foreign commercial paper 51,102 — — 51,102 U.S. and foreign corporate debt securities 56,691 38 — 56,729 Asset-backed securities 39,756 33 — 39,789 U.S. treasury securities 18,447 9 — 18,456 Total short-term investments 165,996 80 — 166,076 Total marketable securities 184,593 80 — 184,673 The Company’s commercial paper and corporate debt securities consist of U.S. and foreign securities from issuers in various sectors, including finance and industry. The Company’s asset-backed securities are collateralized by credit card receivables and have investment-grade ratings. The Company’s government securities are issued by the U.S. treasury and certain U.S. government-backed agencies. Supranational debt securities consist of securities issued with funding from various national governments, including the U.S. As of December 31, 2020 and 2019, the remaining contractual maturities of the Company’s commercial paper, corporate debt securities, asset-backed securities, U.S. treasury and agency securities and supranational debt securities See Note 2 for further information regarding the fair value of the Company’s financial instruments.

Certain Balance Sheet Items

Certain Balance Sheet Items	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Certain Balance Sheet Items	4. Certain Balance Sheet Items Property and equipment consist of the following (in thousands): December 31, 2020 2019 Leasehold improvements $ 2,430 $ 2,430 Office and computer equipment 290 290 Purchased software 44 44 Furniture and fixtures 451 430 Total 3,215 3,194 Less: Accumulated depreciation and amortization (1,454 ) (785 ) Property and equipment, net $ 1,761 $ 2,409 Depreciation and amortization expense for the years ended December 31, 2020 and 2019 was approximately $0.6 million and $0.6 million, respectively, and was recorded in both research and development expense and general and administrative expense in the consolidated statements of operations and comprehensive loss. All of our property and equipment is located in the U.S. Other accrued liabilities consist of the following (in thousands): December 31, 2020 2019 Accrued compensation $ 3,769 $ 2,013 Accrued professional fees and other 659 302 Current portion of operating lease liability 482 407 Total other accrued liabilities $ 4,910 $ 2,722

License Agreements

License Agreements	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License Agreements	5. 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 PPAR d d d d d d d an % royalty on net sales of PPAR d Products. amounts were incurred or accrued for this agreement as of and for the years ended December , and . In June , 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 diabetes and other disorders and received a one-time nonrefundable technology access fee related to the agreements. The Company received a termination notice from Janssen, effectively ending these development and licensing agreements in early . In , the Company exercised an option pursuant to the terms of one of the original agreements to continue work to research, develop and commercialize compounds with activity against an undisclosed metabolic disease target. Janssen granted the Company an exclusive, worldwide license (with rights to sublicense) under the Janssen know-how and patents to research, develop, make, have made, use, offer for sale and sell such compounds. The Company has full control and responsibility over the research, development and registration of any products developed and/or discovered from the metabolic disease target and is required to use diligent efforts to conduct all such activities. DiaTex, Inc. In June 1998, the Company ent e know-how (the covered IP). As part of the license agreement, the Company received an exclusive worldwide license, including as to DiaTex, to use the covered IP to develop and commercialize the licensed products. The Company also retained the right to sub-license the covered IP. The license agreement contains a $ per month license fee as well as a requirement to make additional payments for development achievements and royalty payments on any sales of licensed products. DiaTex is entitled to up to $ million for the future development of arhalofenate, as well as royalty payments on commercial sales of products containing arhalofenate. In December 2016, agreement was amended by the parties to change the timing of a specified development milestone. No development payments were made or due as of and for the years ended December 31, 2020 and 2019 and no royalties have been paid to date.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Indemnification In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnification, including indemnification associated with product liability or infringement of intellectual property rights. The Company’s exposure under these agreements is unknown because it involves future claims that may be made against the Company that may be, but have not yet been, made. To date, the Company has not paid any claims or been required to defend any action related to these indemnification obligations, and no amounts have been accrued in the accompanying consolidated balance sheets related to these indemnification obligations. The Company has agreed to indemnify its officers and directors for losses and costs incurred in connection with certain events or occurrences, including advancing money to cover certain costs, subject to certain limitations. The maximum potential amount of future payments the Company could be required to make under this indemnification is unlimited; however, the Company maintains insurance policies that may limit its exposure and may enable it to recover a portion of any future amounts paid. Assuming the applicability of coverage, the willingness of the insurer to assume coverage, and subject to certain retention, loss limits, and other policy provisions, the Company believes the fair value of these indemnification obligations is not material. Accordingly, the Company has not recognized any liabilities relating to these obligations as of December 31, 2020 and 2019. No assurances can be given that the covering insurers will not attempt to dispute the validity, applicability, or amount of coverage without expensive litigation against these insurers, in which case the Company may incur substantial liabilities as a result of these indemnification obligations. Genfit Litigation On January 15, 2021, Genfit S.A. (Genfit) filed a complaint against the Company in the U.S. District Court for the Northern District of California, The Complaint seeks damages in an unspecified amount as well as injunctive relief. The Company has stated in pleadings that trials.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	7. 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 that commenced January 16, 2014 and was amended on April 16, 2018. At December 31, 2020 and December 31, 2019, the Company’s lease portfolio had a weighted average remaining term of 3.1 years, and 4.1 years, respectively, 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 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 at December 31, 2020 and December 31, 2019 was 12.6% and 12.6%, respectively. For the years ended December 31, 2020 and 2019, the Company incurred $0.5 million and $0.5 million, respectively, of lease costs included in operating expenses in the consolidated statements of operations and comprehensive loss 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 1 right-of-use short-term portion of the operating lease 1.2 long-term portion of operating lease As of December 31, 2020, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Year ending December 31, 2021 667 2022 686 2023 707 2024 30 Total undiscounted future minimum lease payments $ 2,090 Less: imputed interest 346 Total operating lease liability $ 1,744 Less: current portion of operating lease liability 482 Long-term portion of lease liability $ 1,262

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Stockholders' Equity	8. Stockholders’ Equity The Company is authorized to issue 10,000,000 shares of preferred stock as of December 31, 2020 and 2019, and 200,000,000 and 100,000,000 shares of common stock as of December 31, 2020 and 2019, respectively. In July 2020, the Company filed a $200.0 million registration statement on Form S- 3 at-the-market The Company had reserved shares of authorized but unissued common stock as follows: December 31, 2020 2019 2013 Plan 9,080,230 9,143,863 2020 Plan 750,000 — Total reserved shares of common stock 9,830,230 9,143,863 Sale of Common Stock On March 8, 2019, pursuant to a shelf registration statement on Form S-3, 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 Plans and Stock-Based Com

Stock Plans and Stock-Based Compensation	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock Plans and Stock-Based Compensation	9. Stock Plan s Stock Plans In September 2013, the Company’s stockholders approved the 2013 Equity Incentive Plan (the 2013 Plan), under which shares of common stock are reserved for the granting of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance stock awards, performance cash awards and other stock awards by the Company. These awards may be granted to employees, members of the Board of Directors, and consultants. The 2013 Plan has a term of ten years and replaced the 2003 Equity Incentive Plan, which had similar terms. The 2013 Plan permits the Company to (i) grant incentive stock options to directors and employees at not less than 100% of the fair value of common stock on the date of grant; (ii) grant nonqualified options to employees, directors, and consultants at not less than 85% of fair value; (iii) award stock bonuses; and (iv) grant rights to acquire restricted stock at not less than 85% of fair value. Options generally vest over a four year period and have a term of ten years. Options granted to 10% stockholders have a maximum term of five years and require an exercise price equal to at least 110% of the fair value on the date of grant. The exercise price of all options granted to date has been at least equal to the fair value of common stock on the date of grant. Stock option exercises are settled with shares reserved under the 2013 Plan. st ten years st st In October 2020, the Company’s board of directors approved the 2020 New Hire Plan (the 2020 Plan), under which shares of common stock are reserved for the granting of nonqualified stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance stock awards, performance cash awards and other stock awards by the Company as an inducement to prospective new hire employees of the Company. The 2020 Plan has a term of ten years. The 2020 Plan permits the Company to (i) grant nonqualified options to new hire employees at not less than 85% of fair value; (ii) award stock bonuses; and (iii) grant rights to acquire restricted stock at not less than 85% of fair value. Options generally vest over a four year period and have a term of ten years. The share reserve under the 2020 may be increased at the discretion of and approval by the board of directors. No options have been granted to date. Stock Plan Activity As of December 31, 2020, there were 167,159 shares available for grant under the 2013 Plan and an additional 750,000 s shares available for grant under both plans as of December 31, 2020. In December 2020, the Board of Directors reduced the automatic share increase in the 2013 Plan share reserve that was to take place on January 1, 2021 from The following table summarizes activity in the Company’s stock option grants, including performance options: Shares Subject to Outstanding Options Weighted Average Exercise Price of Options Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Outstanding as of December 31, 2019 6,726,695 $ 7.88 Options granted 3,611,593 4.84 Options exercised (63,633 ) 1.44 Options forfeited (492,931 ) 11.46 Options expired (970,094 ) 9.02 Outstanding as of December 31, 2020 8,811,630 $ 6.35 7.60 $ 9,507 Vested and expected to vest as of December 31, 2020 8,811,630 6.35 7.60 $ 9,507 Exercisable as of December 31, 2020 4,789,242 $ 6.57 6.49 $ 5,734 The total intrinsic value of options exercised was $0.4 million and $0.4 million for the years ended December 31, 2020 and 2019, respectively. The total fair value of options vested was $3.3 million and $9.9 million for the years ended December 31, 2020 and 2019, respectively. As of December 31, 2020, unamortized stock-based compensation expense of $17.9 million is expected to be recognized over a weighted average period of 2.8 years. Incentive Awards In December 2013, January 2014, and April 2014, as permitted by the 2013 Plan, the Company issued certain incentive awards to directors, employees and a consultant which are subject to 252,752 shares of the Company’s common stock and are exercisable at a weighted average price of $5.21 per share when vested. The Company may determine at its option whether to settle exercised awards in shares of common stock or in cash. Each recipient’s incentive award defines the number of common shares that may be acquired upon exercise provided the Company chooses to settle in shares. For awards settled in cash, the Company must pay the recipient the excess of the fair market value of the Company’s common stock on the date of exercise over the exercise price paid by the recipient multiplied by the number of shares the recipient would be entitled to receive had the award been settled in shares of the Company’s common stock. Pursuant to their terms, the incentive awards have a term of 10 years and were initially scheduled to vest 100% on the second anniversary of their grant date. However, as a result of the approval by the Company’s stockholders of a 500,000 share increase to the 2013 Plan’s share reserve in June 2014, the incentive awards were automatically modified to vest monthly over four years effective from their grant date. The Company recognized the value of the incentive awards over the remaining four year vesting period which ended in the first quarter of 2018. The Company recorded no s Stock-Based Compensation Expense Stock-based compensation expense is included in the consolidated statements of operations and comprehensive loss and is as follows (in thousands): Year Ended 2020 2019 Research and development $ 2,739 $ 4,361 General and administrative 4,396 5,197 Restructuring charges 189 910 Total stock-based compensation expense $ 7,324 $ 10,468 Valuation Assumptions The following table presents the weighted-average assumptions the Company used in the Black-Scholes option-pricing model to derive the grant date fair values of stock options granted in each of the years presented along with the resulting estimated weighted-average grant date fair values per share: Year Ended 2020 2019 Expected term (years) 6.1 6.2 Expected volatility 105 % 76 % Risk-free interest rate 0.4 % 2.1 % Expected dividend yield — — Weighted-average grant date fair value per share $ 3.91 $ 5.60 Expected Term The Company does not believe it can currently place reliance on its historical exercise and post-vesting termination activity to provide accurate data for estimating the expected term. Therefore, for stock option grants made during the years ended December 31, 2020 and 2019, the Company has elected to use the simplified method for estimating the expected term, which is an average of the contractual term of the options and its ordinary vesting period. The expected term represents the period of time that options are expected to be outstanding. Expected Volatility As the Company has had limited trading history for its common stock, the expected stock price volatility for the Company’s common stock was estimated historically by considering the volatility rates of similar publicly traded peer entities within the life sciences industry prior to 2020 in a blended volatility methodology which weighted our own historical volatility as well as the historical volatility of the peer entities over a period commensurate with the expected term of the awards granted during the year. In 2020, the Company determined its historical stock price data was sufficient to exclusively estimate volatility thereafter. The change in estimate did not have a material impact on the Company’s estimated fair value of its awards. Risk-Free Interest Rate The risk-free interest rate assumption was based on U.S. treasury instruments with constant maturities whose term was consistent with the expected term of stock options granted by the Company. Expected Dividend Yield The Company has never declared or paid cash dividends and does not plan to pay cash dividends in the foreseeable future. Consequently, the Company uses an expected dividend yield of zero.

401(k) Plan

401(k) Plan	12 Months Ended
	Dec. 31, 2020
Postemployment Benefits [Abstract]
401(k) Plan	10. 401(k) Plan The Company provides a qualified 401(k) savings plan for its employees. All employees are eligible to participate, provided they meet the requirements of the plan. As is permitted under the plan, the Company has elected to match employee contributions up to $750 and accordingly matching contributions totaling an insignificant amount were made in the years ended December 31, 2020 and 2019.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes No provision for U.S. income taxes exists due to tax losses incurred in all periods presented. All losses incurred were U.S. based. Significant components of the Company’s deferred tax assets are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Federal and state net operating loss carryforwards $ 123,144 $ 107,213 State and federal research and development tax credit carryforwards 28,861 25,661 Capitalized research and development 2,363 4,725 Stock-based compensation 3,822 3,562 Other 1,256 1,199 Total deferred tax assets 159,446 142,360 Deferred tax liabilities: Depreciation and amortization (269 ) (372 ) Other (57 ) (49 ) Total deferred tax liabilities (326 ) (421 ) Valuation allowance (159,120 ) (141,939 ) Net deferred tax assets $ — $ — Realization of the net deferred tax assets is dependent upon future taxable income, if any, the amount and timing of which is uncertain. Based on the weight of available positive and negative objective evidence, management believes it more likely than not that the Company’s deferred tax assets are not realizable. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The net valuation allowance increased by $17.2 million and $23.6 million due to the increase in the Company’s taxable losses during the years ended December 31, 2020 and 2019, respectively. The following is a reconciliation of the expected statutory federal income tax provision to the actual income tax provision (in thousands): December 31, 2020 2019 Income tax benefit at federal statutory tax rate $ (10,707 ) $ (21,589 ) Change in valuation allowance 17,181 23,587 State income taxes, net of federal benefit (4,768 ) 3,810 Research credits (2,911 ) (6,555 ) Cancelled options 982 315 Other 223 432 Income tax (benefit) expense $ — $ — Pursuant to Internal Revenue Code (IRC), Section 382 and 383, use of the Company’s U.S. federal and state net operating loss and research and credit carryforwards may be limited in the event of a cumulative change in ownership of more than 50.0% within a three-year period. The Company completed an analysis under IRC Sections 382 and 383 through December 21, 2007 and determined that the Company’s net operating losses and research and development credits were subject to limitations due to changes in ownership through December 31, 2007. The net operating loss carryforwards reflected in the deferred tax assets at December 31, 2020 have been adjusted to reflect Section 382 limitations resulting from that change. The Company has been in a net operating loss position since 2008. The Company has not performed any additional analysis for IRC Sections 382 and 383 and there is a risk that additional changes in ownership could have occurred since December 31, 2007. If a change in ownership were to have occurred, additional net operating loss and tax credit carryforwards could be eliminated or restricted. If eliminated, the related asset would be removed from the deferred tax asset schedule with a corresponding reduction in the valuation allowance. As of December 31, 2020, the Company had federal net operating loss carryforwards of $490.4 million and state net operating loss carryforwards of $288.6 million to offset future taxable income, if any. In addition, the Company had federal research and development tax credit carryforwards of $10.1 million, federal orphan drug tax credit carryforwards of $21.4 million, and state research and development tax credit carryforwards of $5.8 million. If not utilized, the federal net operating losses for the years beginning before January 1, 2018 of $255.7 million will expire beginning in 2024 through 2037, and the federal net operating losses for the tax years beginning after January 1, 2018 of $234.7 million will be carried forward indefinitely (subject to certain utilization limitations). The state net operating loss carryforwards will expire beginning in The following table summarizes activity related to the Company’s gross unrecognized tax benefits (in thousands): Total Balances as of December 31, 2018 $ 4,584 Increases related to prior year tax positions 83 Increases related to 2019 tax positions 1,719 Balances as of December 31, 2019 6,386 Decreases related to prior year tax positions (58 ) Increases related to 2020 tax positions 877 Balances as of December 31, 2020 $ 7,205 The unrecognized tax benefits, if recognized, would not have an impact on the Company’s effective tax rate assuming the Company continues to maintain a full valuation allowance position. Based on prior year’s operations and experience, the Company does not expect a significant change to its unrecognized tax benefits over the next twelve months. The unrecognized tax benefits may increase or change during the next year for unexpected or unusual items for items that arise in the ordinary course of business. The Company files income tax returns in the U.S. federal and California jurisdictions and is not currently under examination by federal, state, or local taxing authorities for any open tax years. Due to net operating loss carryforwards, all years remain open for income tax examination by tax authorities in the U.S. and states in which the Company files tax returns.

Restructuring

Restructuring	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Restructuring and Related Activities Disclosure	12. Restructuring In December 2019, the Company commenced a reorganization plan to reduce its operating costs and better align its workforce with the needs of its business following the Company’s November 2019 announcement that it had halted clinical development of seladelpar. The restructuring liability is included in current liabilities on the consolidated balance sheets. The Company incurred restructuring charges of $5.1 million for the year ended December 31, 2019 and a restructuring benefit of $0.7 million for the year ended December 31, 2020. Restructuring charges incurred under this plan primarily consisted of employee termination benefits and contract termination costs associated with nonrefundable prepayments and exit fees relating to third-party manufacturers that the Company contracted with for clinical supplies. Employee termination benefits include severance costs, employee-related benefits, supplemental one-time non-cash The following table summarizes the accrued restructuring liabilities and utilization by cost type associated with the restructuring activities (in thousands): Termination Contract Total Balances as of December 31, 2018 $ — $ — $ — Restructuring charges 2,912 413 3,325 Reductions for cash payments (132 ) — (132 ) Balances as of December 31, 2019 2,780 413 3,193 Change in estimates (539 ) (413 ) (952 ) Reductions for cash payments (2,223 ) — (2,223 ) Balances as of December 31, 2020 $ 18 $ — $ 18 In addition to the activity in the above table, during the year ended December 31, 2019, the Company also recognized $1.8 million in restructuring charges related to $0.9 million of nonrefundable prepaid research and development costs for clinical trial materials no longer expected be delivered and $0.9 million of accelerated vesting for stock-based compensation for executives subject to the reorganization plan. During the year ended December 31, 2020, the activity in the table above reflects a $0.5 million reversal of severance liabilities associated with severance benefits that were forfeited by certain executives pursuant to the terms of their respective employment agreements, and a reversal of $0.4 million of contract termination costs resulting from a subsequent arrangement between the Company and the vendor to waive these costs. In addition to the activity in the above table, during the year ended December 31, 2020, the Company also recognized in restructuring charges $0.2 million of non-cash,

Organization and Description _2

Organization and Description of Business (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Liquidity	Liquidity The Company has incurred net operating losses and negative cash flows from operations since its inception. During the year ended December 31, 2020, the Company incurred a net loss of $51.0 Historically, the Company has incurred substantial research and development expenses in the course of studying 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. Generally, the Company’s ability to achieve profitability is dependent on its ability to successfully develop, acquire or in-license As of December 31, 2020, the Company had cash, cash equivalents and marketable securities totaling $146.3 As the Company continues to advance its clinical studies of seladelpar, cash is considered sufficient to fund the Company’s operating plan into mid-2022. The Company has historically obtained, and expects to obtain in the future, additional financing to fund its business strategy through: future equity offerings; debt financing; one or more possible licenses, collaborations or other similar arrangements with respect to development and/or commercialization rights of the Company’s 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. Market volatility resulting from the global novel coronavirus disease (COVID-19) pandemic or other factors could also adversely impact our ability to access capital when and as needed. Failure to raise sufficient capital when needed could require us to significantly delay, scale back or discontinue one or more of our product development programs or commercialization efforts or other aspects of our business plans, and our operating results and financial condition would be adversely affected. In July 2020, the Company filed a $200.0 million registration statement on Form S-3 at-the-market
Basis of Presentation and Use of Estimates	Basis of Presentation and Use of Estimates The accompanying consolidated financial statements are comprised of the accounts 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 consolidated statements have been prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP), which requires management to make informed estimates and assumptions that impact the amounts and disclosures reported in the consolidated financial statements and accompanying notes. Accounting estimates and assumptions are inherently uncertain. 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. 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 generally 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, accrued interest receivables, prepaid expenses, other current assets, accounts payable, and accrued expenses. 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, receivables, prepaid expenses, other current assets, accounts payable, and accrued expenses 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 — Q Level 2 — Level 3 — 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 December 31, 2020 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 22,415 $ — $ — $ 22,415 Total cash equivalents 22,415 — — 22,415 Marketable securities: U.S. and foreign commercial paper — 38,561 — 38,561 U.S. and foreign corporate debt securities — 29,189 — 29,189 Asset-backed securities — 7,885 — 7,885 U.S. agency securities — 23,994 — 23,994 U.S. treasury securities — 15,499 — 15,499 Supranational debt securities — 3,002 — 3,002 Total marketable securities — 118,130 — 118,130 Total assets measured at fair value $ 22,415 $ 118,130 $ — $ 140,545 As of December 31, 2019 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 18,597 $ — $ — $ 18,597 Total cash equivalents 18,597 — — 18,597 Marketable securities: U.S. and foreign commercial paper — 51,102 — 51,102 U.S. and foreign corporate debt securities — 56,729 — 56,729 Asset-backed securities — 39,788 — 39,788 U.S. treasury securities — 18,457 — 18,457 Total marketable securities — 166,076 — 166,076 Total assets measured at fair value $ 18,597 $ 166,076 $ — $ 184,673 The Company estimates the fair value of its money market funds, corporate debt, asset backed securities, commercial paper U.S. treasury and agency securities and supranational debt 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. See Note 3 for further discussion regarding the carrying value of the Company’s financial instruments.
Cash, Cash Equivalents, and Marketable Securities	Cash, Cash Equivalents, and Marketable Securities The Company considers all highly liquid investments with an original maturity of 90 days or less at the time of purchase to be cash equivalents. Cash and cash equivalents consist of deposits with commercial banks in checking, interest-bearing, and money market funds. The Company invests excess cash in marketable securities with high credit ratings that are classified in Level 1 or Level 2 of the fair value hierarchy. These securities consist primarily of corporate debt, commercial paper, asset-backed securities, U.S. treasury and agency securities and supranational debt securities and are classified as “available-for-sale.” The Company considers marketable securities as short-term investments if the maturity date is less than 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 consolidated statements of operations and comprehensive loss. Unrealized holding gains and losses are reported in accumulated other comprehensive loss in the 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.
Concentration of Credit Risk	Concentration of Credit Risk Cash, cash equivalents, and marketable securities consist of financial instruments that potentially subject the Company to a concentration of credit risk to the extent of the fair value recorded on 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 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.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost, less accumulated depreciation and amortization. Depreciation and amortization are calculated using the straight-line method, and the costs are amortized over the estimated useful lives of the respective assets, which are generally three to seven years. Leasehold improvements are amortized over the shorter of the useful lives or the non-cancelable
Impairment of Long-Lived Assets	Long-Lived Assets The Company reviews the carrying value long-lived assets, including right-of-use
Leases	Leases The Company has one lease, a non-cancelable operating lease agreement for its corporate office. 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 consolidated balance sheets at December 31, 2020 and 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. The Company does not record leases on our consolidated balance sheets when a lease has a term of one year or less.
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 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. 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.
Restructuring Charges	Restructuring Charges The Company recognizes restructuring charges related to reorganization plans that have been committed to by management and when liabilities have been incurred. In connection with these activities, the Company records one-time One-time The recognition of restructuring charges requires the Company to make certain judgments and estimates regarding the nature, timing and amount of costs associated with the planned reorganization plan. To the extent the Company’s actual results differ from its estimates and assumptions, the Company may be required to revise the estimates of future accrued restructuring liabilities, requiring the recognition of additional restructuring charges or the reduction of accrued restructuring liabilities already recognized. Such changes to previously estimated amounts may be material to the consolidated financial statements. Changes in the estimates of the restructuring charges are recorded in the period the change is determined. At the end of each reporting period, the Company evaluates the remaining accrued restructuring balances to ensure that no excess accruals are retained, and the utilization of the provisions are for their intended purpose in accordance with developed restructuring plans.
Stock-Based Compensation	Stock-Based Compensation 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 with service conditions and forfeitures are accounted for as they occur. 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. If actual results are not consistent with the Company’s assumptions 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.
Income Taxes	Income Taxes The Company utilizes the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between the financial reporting and the tax bases of assets and liabilities and are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. A valuation allowance is recorded when it is more likely than not that all or part of a deferred tax asset will not be realized. When the Company establishes or reduces the valuation allowance related to the deferred tax assets, the provision for income taxes will increase or decrease, respectively, in the period such determination is made. The accounting guidance for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination based on the technical merits of the position. The Company is required to file federal and state income tax returns in the United States. The preparation of these income tax returns requires the Company to interpret the applicable tax laws and regulations in effect that could affect the amount of tax paid to these jurisdictions. The Company records interest related to income tax reserves, if any, as interest expense, and any penalties would be recorded as other expense in the consolidated statements of operations and comprehensive loss. In March 2020, the Families First Coronavirus Response Act (FFCR Act) and the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) were each enacted in response to the COVID-19 In June 2020, Assembly Bill 85 (A.B. 85) was signed into California law. A.B. 85 provides for a three-year suspension of the use of net operating losses for medium and large businesses and a three-year cap on the use of business incentive tax credits to offset no more than $5.0 million of tax per year. A.B. 85 suspends the use of net operating losses for taxable years 2020, 2021 and 2022 for certain taxpayers with taxable income of $1.0 million or more. The carryover period for any net operating losses that are suspended under this provision will be extended. A.B. 85 also requires that business incentive tax credits including carryovers may not reduce the applicable tax by more than $5.0 million for taxable years 2020, 2021 and 2022. In December 2020, the Consolidated Appropriations Act, 2021 (CAA) was signed into law. The CAA included additional funding through tax credits as part of its economic package for 2021. The FFCR Act, CARES Act, A.B. 85 and CAA did not have a material impact on the Company’s consolidated financial statements; however, the Company continues to examine the impacts the FFCR Act, CARES Act, A.B. 85 and CAA may have on its business, results of operations, financial condition and liquidity.
Comprehensive Loss	Comprehensive Loss Comprehensive loss includes net loss and net unrealized gains and losses on marketable securities, which are presented in a single continuous statement. Other comprehensive (loss) gain is also disclosed in the consolidated balance sheets and statements of stockholders’ equity in accumulated other comprehensive income (loss), and is stated net of related tax effects, if any.
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per share of common stock is based on the weighted average number of shares of common stock outstanding equivalents during the period. Diluted net loss per share of common stock is calculated as the weighted average number of shares of common stock outstanding adjusted to include the assumed exercises of stock options, if dilutive. In all periods presented, the Company’s outstanding stock options were excluded from the calculation of net loss per share because the effect would be antidilutive. The following table sets forth the computation of basic and diluted net loss per share (in thousands, except share and per share amounts): Year Ended December 31, 2020 2019 Numerator: Net loss $ (50,986 ) $ (102,808 ) Denominator: Weighted average number of common stock shares outstanding 68,893,127 67,033,046 Net loss per share $ (0.74 ) $ (1.53 ) 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): Year Ended December 31, 2020 2019 Common stock options 8,812 6,727 Incentive awards 101 101 Total 8,913 6,828
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements ASU 2018-18 In November 2018, the FASB issued ASU 2018-18, Clarifying the Interaction between Topic 808 and Topic 606 ASU 2018-15 In August 2018, the FASB issued ASU No. 2018-15, Intangibles Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract internal-use ASU 2018-13 In August 2018, the FASB issued ASU 2018-13, ( ): Disclosure Framework — C the reporting period and disclosing the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The amendment became effective for the Company on January 1, 2020. The adoption of this standard did not have a material impact on its consolidated financial statements. Recently Issued Accounting Pronouncements ASU 2016-13 In June 2016, the FASB issued ASU No. 2016-13, s — C Measurement of Credit Losses on Financial Instruments available-for-sale No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842) ASU 2019-12 In December 2019, the FASB issued ASU 2019-12, step-up

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
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 December 31, 2020 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 22,415 $ — $ — $ 22,415 Total cash equivalents 22,415 — — 22,415 Marketable securities: U.S. and foreign commercial paper — 38,561 — 38,561 U.S. and foreign corporate debt securities — 29,189 — 29,189 Asset-backed securities — 7,885 — 7,885 U.S. agency securities — 23,994 — 23,994 U.S. treasury securities — 15,499 — 15,499 Supranational debt securities — 3,002 — 3,002 Total marketable securities — 118,130 — 118,130 Total assets measured at fair value $ 22,415 $ 118,130 $ — $ 140,545 As of December 31, 2019 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 18,597 $ — $ — $ 18,597 Total cash equivalents 18,597 — — 18,597 Marketable securities: U.S. and foreign commercial paper — 51,102 — 51,102 U.S. and foreign corporate debt securities — 56,729 — 56,729 Asset-backed securities — 39,788 — 39,788 U.S. treasury securities — 18,457 — 18,457 Total marketable securities — 166,076 — 166,076 Total assets measured at fair value $ 18,597 $ 166,076 $ — $ 184,673
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): Year Ended December 31, 2020 2019 Numerator: Net loss $ (50,986 ) $ (102,808 ) Denominator: Weighted average number of common stock shares outstanding 68,893,127 67,033,046 Net loss per share $ (0.74 ) $ (1.53 )
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): Year Ended December 31, 2020 2019 Common stock options 8,812 6,727 Incentive awards 101 101 Total 8,913 6,828

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Marketable Available-for-Sale Securities	Marketable available-for-sale securities consist of the following (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of December 31, 2020: Cash equivalents: Money market funds $ 22,415 $ — $ — $ 22,415 Total cash equivalents 22,415 — — 22,415 Short-term investments: U.S. and foreign commercial paper 38,561 — — 38,561 U.S. and foreign corporate debt securities 29,186 7 (4 ) 29,189 Asset-backed securities 7,883 2 — 7,885 U.S. treasury securities 23,991 3 — 23,994 U.S. agency securities 15,498 1 — 15,499 Supranational debt securities 3,003 — (1 ) 3,002 Total short-term investments 118,122 13 (5 ) 118,130 Total marketable securities 140,537 13 (5 ) 140,545 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value As of December 31, 2019: Cash equivalents: Money market funds $ 18,597 $ — $ — $ 18,597 Total cash equivalents 18,597 — — 18,597 Short-term investments: U.S. and foreign commercial paper 51,102 — — 51,102 U.S. and foreign corporate debt securities 56,691 38 — 56,729 Asset-backed securities 39,756 33 — 39,789 U.S. treasury securities 18,447 9 — 18,456 Total short-term investments 165,996 80 — 166,076 Total marketable securities 184,593 80 — 184,673

Certain Balance Sheet Items (Ta

Certain Balance Sheet Items (Tables)	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Property and Equipment	Property and equipment consist of the following (in thousands): December 31, 2020 2019 Leasehold improvements $ 2,430 $ 2,430 Office and computer equipment 290 290 Purchased software 44 44 Furniture and fixtures 451 430 Total 3,215 3,194 Less: Accumulated depreciation and amortization (1,454 ) (785 ) Property and equipment, net $ 1,761 $ 2,409
Other Accrued Liabilities	Other accrued liabilities consist of the following (in thousands): December 31, 2020 2019 Accrued compensation $ 3,769 $ 2,013 Accrued professional fees and other 659 302 Current portion of operating lease liability 482 407 Total other accrued liabilities $ 4,910 $ 2,722

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Summary of Maturities of Operating Lease Liabilities	As of December 31, 2020, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Year ending December 31, 2021 667 2022 686 2023 707 2024 30 Total undiscounted future minimum lease payments $ 2,090 Less: imputed interest 346 Total operating lease liability $ 1,744 Less: current portion of operating lease liability 482 Long-term portion of lease liability $ 1,262

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Reserved Shares of Authorized but Unissued Common Stock	The Company had reserved shares of authorized but unissued common stock as follows: December 31, 2020 2019 2013 Plan 9,080,230 9,143,863 2020 Plan 750,000 — Total reserved shares of common stock 9,830,230 9,143,863

Stock Plans and Stock-Based C_2

Stock Plans and Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Summary of Stock Option Grants, Including Performance Options	The following table summarizes activity in the Company’s stock option grants, including performance options: Shares Subject to Outstanding Options Weighted Average Exercise Price of Options Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Outstanding as of December 31, 2019 6,726,695 $ 7.88 Options granted 3,611,593 4.84 Options exercised (63,633 ) 1.44 Options forfeited (492,931 ) 11.46 Options expired (970,094 ) 9.02 Outstanding as of December 31, 2020 8,811,630 $ 6.35 7.60 $ 9,507 Vested and expected to vest as of December 31, 2020 8,811,630 6.35 7.60 $ 9,507 Exercisable as of December 31, 2020 4,789,242 $ 6.57 6.49 $ 5,734
Summary of Stock-Based Compensation Expense	Stock-based compensation expense is included in the consolidated statements of operations and comprehensive loss and is as follows (in thousands): Year Ended 2020 2019 Research and development $ 2,739 $ 4,361 General and administrative 4,396 5,197 Restructuring charges 189 910 Total stock-based compensation expense $ 7,324 $ 10,468
Estimated Weighted-Average Grant Date Fair Value	The following table presents the weighted-average assumptions the Company used in the Black-Scholes option-pricing model to derive the grant date fair values of stock options granted in each of the years presented along with the resulting estimated weighted-average grant date fair values per share: Year Ended 2020 2019 Expected term (years) 6.1 6.2 Expected volatility 105 % 76 % Risk-free interest rate 0.4 % 2.1 % Expected dividend yield — — Weighted-average grant date fair value per share $ 3.91 $ 5.60

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Components of Deferred Tax Assets	Significant components of the Company’s deferred tax assets are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Federal and state net operating loss carryforwards $ 123,144 $ 107,213 State and federal research and development tax credit carryforwards 28,861 25,661 Capitalized research and development 2,363 4,725 Stock-based compensation 3,822 3,562 Other 1,256 1,199 Total deferred tax assets 159,446 142,360 Deferred tax liabilities: Depreciation and amortization (269 ) (372 ) Other (57 ) (49 ) Total deferred tax liabilities (326 ) (421 ) Valuation allowance (159,120 ) (141,939 ) Net deferred tax assets $ — $ —
Summary of Gross Unrecognized Tax Benefits	The following table summarizes activity related to the Company’s gross unrecognized tax benefits (in thousands): Total Balances as of December 31, 2018 $ 4,584 Increases related to prior year tax positions 83 Increases related to 2019 tax positions 1,719 Balances as of December 31, 2019 6,386 Decreases related to prior year tax positions (58 ) Increases related to 2020 tax positions 877 Balances as of December 31, 2020 $ 7,205

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2020
Restructuring and Related Activities [Abstract]
Schedule Of Restructuring And Related Costs	The following table summarizes the accrued restructuring liabilities and utilization by cost type associated with the restructuring activities (in thousands): Termination Contract Total Balances as of December 31, 2018 $ — $ — $ — Restructuring charges 2,912 413 3,325 Reductions for cash payments (132 ) — (132 ) Balances as of December 31, 2019 2,780 413 3,193 Change in estimates (539 ) (413 ) (952 ) Reductions for cash payments (2,223 ) — (2,223 ) Balances as of December 31, 2020 $ 18 $ — $ 18

Organization and Description _3

Organization and Description of Business - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)Segment	Dec. 31, 2019USD ($)	Jul. 31, 2020USD ($)	Jul. 13, 2020USD ($)
Class of Stock [Line Items]
Common Stock, Value, Registered For Issuance				$ 200,000
Number of operating segments | Segment	1
Net loss	$ (50,986)	$ (102,808)
Cash flows from operating activities	(44,725)	(97,911)
Accumulated deficit	(676,858)	$ (625,872)
Cash and cash equivalents and marketable securities	$ 146,300
ATM Offering [Member]
Class of Stock [Line Items]
Common stock value subscribed			$ 75,000	$ 75,000
Common Stock, Value, Registered For Issuance			$ 200,000

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	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 140,545	$ 184,673
Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	22,415	18,597
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	22,415	18,597
Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	118,130	166,076
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	38,561	51,102
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	29,189	56,729
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	7,885	39,788
Short-term Investments [Member] | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	23,994
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	15,499	18,457
Short-term Investments [Member] | Supranational Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	3,002
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	22,415	18,597
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	22,415	18,597
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	22,415	18,597
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	118,130	166,076
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	118,130	166,076
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	38,561	51,102
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	29,189	56,729
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	7,885	39,788
Level 2 [Member] | Short-term Investments [Member] | U.S. agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	23,994
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	15,499	$ 18,457
Level 2 [Member] | Short-term Investments [Member] | Supranational Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 3,002

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020
Product Information [Line Items]
Minimum taxable income fixed for suspension of tax credit offset		$ 5
Average taxable income fixed for suspension of use of net operating losses		1
Maximum Threshold On Tax Credit Offset		$ 5
Cash and cash equivalents, maturity description	90 days or less
Maximum [Member]
Product Information [Line Items]
Short-term contractual maturities	1 year
Property and equipment, estimated useful lives	7 years
Minimum [Member]
Product Information [Line Items]
Short-term contractual maturities	1 year

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net loss	$ (50,986)	$ (102,808)
Denominator:
Weighted average number of common stock shares outstanding	68,893,127	67,033,046
Net loss per share	$ (0.74)	$ (1.53)

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Anti-Dilutive Securities Excluded from the Computation of Diluted Net Loss per Share (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share	8,913	6,828
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	8,812	6,727
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	101	101

Marketable Securities - Marketa

Marketable Securities - Marketable Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 118,130	$ 166,076
Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	22,415	18,597
Estimated Fair Value	22,415	18,597
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	22,415	18,597
Estimated Fair Value	22,415	18,597
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	118,122	165,996
Gross Unrealized Gains	13	80
Gross Unrealized Losses	(5)
Estimated Fair Value	118,130	166,076
Short-term Investments [Member] | U.S. and Foreign Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	38,561	51,102
Estimated Fair Value	38,561	51,102
Short-term Investments [Member] | U.S. and Foreign Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	29,186	56,691
Gross Unrealized Gains	7	38
Gross Unrealized Losses	(4)
Estimated Fair Value	29,189	56,729
Short-term Investments [Member] | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,883	39,756
Gross Unrealized Gains	2	33
Estimated Fair Value	7,885	39,789
Short-term Investments [Member] | U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,991	18,447
Gross Unrealized Gains	3	9
Estimated Fair Value	23,994	18,456
Short-term Investments [Member] | US Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,498
Gross Unrealized Gains	1
Estimated Fair Value	15,499
Short-term Investments [Member] | Supranational Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,003
Gross Unrealized Losses	(1)
Estimated Fair Value	3,002
Maketable Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	140,537	184,593
Gross Unrealized Gains	13	80
Gross Unrealized Losses	(5)
Estimated Fair Value	$ 140,545	$ 184,673

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Asset-backed Securities [Member] | Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Remaining contractual maturities of marketable securities	1 year	1 year
U.S. and Foreign Commercial Paper [Member] | Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Remaining contractual maturities of marketable securities	1 year	1 year
U.S. and Foreign Corporate Debt Securities [Member] | Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Remaining contractual maturities of marketable securities	1 year	1 year
U.S. Treasury Securities [Member] | Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Remaining contractual maturities of marketable securities	1 year	1 year
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Realized gains and losses	$ 0	$ 0
Marketable investments continuous unrealized loss position	$ 0	$ 0

Certain Balance Sheet Items - P

Certain Balance Sheet Items - Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,215	$ 3,194
Less: Accumulated depreciation and amortization	(1,454)	(785)
Property and equipment, net	1,761	2,409
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,430	2,430
Office and Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	290	290
Purchased Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	44	44
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 451	$ 430

Certain Balance Sheet Items - A

Certain Balance Sheet Items - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 0.6	$ 0.6

Certain Balance Sheet Items - O

Certain Balance Sheet Items - Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued compensation	$ 3,769	$ 2,013
Accrued professional fees and other	659	302
Current portion of operating lease liability	482	407
Total other accrued liabilities	$ 4,910	$ 2,722

Collaboration and License Agree

Collaboration and License Agreements - Additional Information (Detail)	1 Months Ended		12 Months Ended
	Jun. 30, 2006	Jun. 30, 1998USD ($)	Dec. 31, 2020USD ($)Agreement	Dec. 31, 2019USD ($)
Janssen Pharmaceutical NV [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Accrued royalties			$ 0	$ 0
Janssen Pharmaceutical NV [Member] | Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales	8.00%
Janssen Pharmaceuticals, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of development and license agreements | Agreement			2
DiaTex, Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Royalty payment			$ 0	0
Monthly license fees		$ 2,000
Potential future development payments		$ 800,000
Development payment			$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Jan. 15, 2021	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Indemnification liabilities		$ 0	$ 0
Accrued in the consolidated balance sheets related to indemnification obligations		$ 0
Subsequent Event [Member]
Loss Contingencies [Line Items]
Loss Contingency, Lawsuit Filing Date	January 15, 2021
Loss Contingency, Name of Plaintiff	Genfit S.A.
Loss Contingency, Allegations	alleging misappropriation of trade secrets and related causes of action based on the Company’s receipt of a Genfit protocol synopsis for Genfit’s Phase 3 clinical trial of its drug candidate elafibranor in patients with PBC
Loss Contingency, Actions Taken by Defendant	The Company intends to defend itself vigorously and does not believe that the ultimate outcome of this matter as a loss is probable nor that any amount is reasonably estimable

Leases - Summary of Maturities

Leases - Summary of Maturities of Operating Lease Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
2021	$ 667
2022	686
2023	707
2024	30
Total undiscounted future minimum lease payments	2,090
Less: Imputed interest	346
Total operating lease liability	1,744	$ 2,100
Less: current portion of operating lease liability	482	407
Long-term portion of lease liability	$ 1,262	$ 1,743

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)ft²Facility	Dec. 31, 2019USD ($)
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term	3 years 1 month 6 days	4 years 1 month 6 days
Lease, option to extend	option to extend for an additional 5 years
Weighted average lease discount rate	12.60%	12.60%
Operating lease right-of-use asset	$ 272	$ 235
Operating lease liability	1,744	2,100
Short term portion of operating lease liability	$ 482	$ 407
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other accrued liabilities	Other accrued liabilities
Long-term portion of operating lease liability	$ 1,262	$ 1,743
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-term portion of operating lease liability	Long-term portion of operating lease liability
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
Operating Expense [Member]
Lessee, Lease, Description [Line Items]
Lease costs	$ 500	$ 500

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Mar. 08, 2019	Dec. 31, 2020	Jul. 31, 2020	Jul. 13, 2020	Mar. 11, 2019
Class of Stock [Line Items]
Common Stock, Value, Registered For Issuance					$ 200,000
Preferred stock, shares authorized	10,000,000		10,000,000
Common stock, shares authorized	100,000,000		200,000,000
Common stock, shares issued	68,882,459	8,000,000	68,946,092			1,200,000
Common stock offering price		$ 12.50
Net proceeds from public offering	$ 107,746	$ 107,700
ATM Offering [Member]
Class of Stock [Line Items]
Common Stock, Value, Registered For Issuance				$ 200,000
Common stock value subscribed				$ 75,000	$ 75,000

Stockholder's Equity - Reserved

Stockholder's Equity - Reserved Shares of Authorized but Unissued Common Stock (Detail) - shares	Jan. 01, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Total reserved shares of common stock		9,830,230	9,143,863
Equity Incentive Plan Two Thousand And Thirteen [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	2,757,843	9,080,230	9,143,863
Equity Incentive Plan Two Thousand and Twenty Plan [Member]
Class of Stock [Line Items]
Total reserved shares of common stock		750,000

Stock Plans and Stock-Based C_3

Stock Plans and Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2013	Jan. 01, 2021	Jun. 30, 2014	Apr. 30, 2014	Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant		917,159
Intrinsic value of options exercised		$ 400	$ 400
Fair value of options vested		3,300	$ 9,900
Unamortized employee and non-employee stock-based compensation expense		$ 17,900
Unamortized employee and non-employee stock-based compensation expense recognized period		2 years 9 months 18 days
Options exercised		3,611,593
Share reserved for issue		9,830,230	9,143,863
Stock-based compensation expense		$ 7,135	$ 9,558
Stock options outstanding		8,811,630	6,726,695
Equity Incentive Plan Two Thousand and Twenty Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, exercise price percentage		85.00%
Shares available for grant		750,000
Options exercised		0
Share reserved for issue		750,000
2013 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, expiration period	10 years
Share based compensation arrangement percentage increase in share reserved	5.00%
Shares available for grant		167,159
Share reserved for issue		9,080,230	9,143,863				2,757,843
2013 Equity Incentive Plan [Member] | Incentive Stock Options for Employees and Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, exercise price percentage	100.00%
2013 Equity Incentive Plan [Member] | Nonqualified Options to Employees, Directors and Consultants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, exercise price percentage	85.00%
2013 Equity Incentive Plan [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, exercise price percentage	85.00%
Share based compensation arrangement by share based payment award, award vesting period	4 years
2013 Equity Incentive Plan [Member] | Stock Options to 10% Stockholders [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, exercise price percentage					110.00%
Share based compensation arrangement by share based payment award, award vesting period					5 years
Incentive Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award, expiration period				10 years
Share based compensation arrangement by share based payment award, award vesting period						4 years
Share reserved for issue								500,000	252,752
Exercisable weighted average price per share										$ 5.21
Stock option plan, Description		vest monthly over four years effective from their grant date
Stock-based compensation expense		$ 0	$ 0
Stock options outstanding		101,441	101,441
Incentive Awards [Member] | First Tranche [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting of shares						100.00%
Maximum [Member] | 2013 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting of shares		5.00%
Minimum [Member] | 2013 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vesting of shares		4.00%

Stock Plans and Stock-Based C_4

Stock Plans and Stock-Based Compensation - Summary of Stock Option Grants, Including Performance Options (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)$ / sharesshares
Shares Subject to Outstanding Options
Outstanding at the beginning of period | shares	6,726,695
Options granted | shares	3,611,593
Options exercised | shares	(63,633)
Options forfeited | shares	(492,931)
Options expired | shares	(970,094)
Outstanding as end of period | shares	8,811,630
Vested and expected to vest | shares	8,811,630
Exercisable | shares	4,789,242
Weighted-Average Exercise Price of Options
Outstanding at the beginning of period | $ / shares	$ 7.88
Options granted | $ / shares	4.84
Options exercised | $ / shares	1.44
Options forfeited | $ / shares	11.46
Options expired | $ / shares	9.02
Outstanding as end of period | $ / shares	6.35
Vested and expected to vest | $ / shares	6.35
Exercisable | $ / shares	$ 6.57
Weighted-Average Remaining Contractual Term (Years)
Outstanding	7 years 7 months 6 days
Vested and expected to vest	7 years 7 months 6 days
Exercisable	6 years 5 months 26 days
Aggregate Intrinsic Value (In Thousands)
Outstanding | $	$ 9,507
Vested and expected to vest | $	9,507
Exercisable | $	$ 5,734

Stock Plans and Stock-Based C_5

Stock Plans and Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 7,324	$ 10,468
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	2,739	4,361
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	4,396	5,197
Restructuring charges [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 189	$ 910

Stock Plans and Stock-Based C_6

Stock Plans and Stock-Based Compensation - Estimated Weighted-Average Grant Date Fair Value (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	6 years 1 month 6 days	6 years 2 months 12 days
Expected volatility	105.00%	76.00%
Risk-free interest rate	0.40%	2.10%
Expected dividend yield	0.00%
Weighted-average grant date fair value per share	$ 3.91	$ 5.60

401(k) Plan - Additional Inform

401(k) Plan - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Employees contribution to qualified savings plan	$ 750,000	$ 750,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax [Line Items]
Description of net operating loss carryforwards, expire period	The state net operating loss carryforwards will expire beginning in 2028 through 2040. The federal research and development and federal orphan drug tax credit carryforwards expire 2021 through 2040, and the state tax credit will carry forward indefinitely.
Provision for income taxes	$ 0	$ 0
Net valuation allowance increase (decrease)	$ 17,200	$ 23,600
Cumulative change in ownership	50.00%
Cumulative change in ownership period	3 years
Significant change to its unrecognized tax benefits over the next twelve months	$ 0
Income tax examination years	all years remain open for income tax examination by tax authorities
Domestic Tax Authority [Member]
Income Tax [Line Items]
Federal net operating loss	$ 490,400
Net operating loss carryforward	490,400
Research and development tax credit carry forwards	21,400
Domestic Tax Authority [Member] | Orphan Drug [Member]
Income Tax [Line Items]
Research and development tax credit carry forwards	$ 10,100
Domestic Tax Authority [Member] | Minimum [Member]
Income Tax [Line Items]
NOL carry forward expiry date	2024
Domestic Tax Authority [Member] | Maximum [Member]
Income Tax [Line Items]
NOL carry forward expiry date	2037
State and Local Jurisdiction [Member]
Income Tax [Line Items]
Federal net operating loss	$ 288,600
Net operating loss carryforward	288,600
Research and development tax credit carry forwards	$ 5,800
State and Local Jurisdiction [Member] | Federal [member]
Income Tax [Line Items]
Federal net operating loss			$ 234,700	$ 255,700
Net operating loss carryforward			$ 234,700	$ 255,700
State and Local Jurisdiction [Member] | Minimum [Member] | Federal [member]
Income Tax [Line Items]
NOL carry forward expiry date	2028
State and Local Jurisdiction [Member] | Maximum [Member] | Federal [member]
Income Tax [Line Items]
NOL carry forward expiry date	2040

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Federal and state net operating loss carryforwards	$ 123,144	$ 107,213
State and federal research and development tax credit carryforwards	28,861	25,661
Capitalized research and development	2,363	4,725
Stock based compensation	3,822	3,562
Other	1,256	1,199
Total deferred tax assets	159,446	142,360
Deferred tax liabilities:
Depreciation and amortization	(269)	(372)
Other	(57)	(49)
Total deferred tax liabilities	(326)	(421)
Valuation allowance	(159,120)	$ (141,939)
Net deferred tax assets	$ 0

Income Taxes - Summary of Recon

Income Taxes - Summary of Reconciliation of Expected Statutory Federal Income Tax Provision to Actual Income Tax Provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income tax benefit at federal statutory tax rate	$ (10,707)	$ (21,589)
Change in valuation allowance	17,181	23,587
State income taxes, net of federal benefit	(4,768)	3,810
Research credits	(2,911)	(6,555)
Cancelled options	982	315
Other	223	432
Income tax (benefit) expense	$ 0	$ 0

Income Taxes - Summary of Gross

Income Taxes - Summary of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Balance at beginning of period	$ 6,386	$ 4,584
Increases related to prior year tax positions	877	83
Decreases related to prior year tax positions	(58)
Increases related to tax positions		1,719
Balance at end of period	$ 7,205	$ 6,386

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Balances as of January	$ 3,193
Restructuring charges		3,325
Change in estimates	(952)
Reductions for cash payments	(2,223)	(132)
Balances as of December	18	3,193
Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Balances as of January	2,780
Restructuring charges		2,912
Change in estimates	(539)
Reductions for cash payments	(2,223)	(132)
Balances as of December	18	2,780
Contract Termination Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balances as of January	413
Restructuring charges		413
Change in estimates	(413)
Balances as of December		$ 413

Restructuring - Additional Info

Restructuring - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring and Impairment charges		$ 5,100
Restructuring charges	$ (705)	5,075
Restructuring benefit	700
Change in estimates	952
Non cash,Restructuring Stock based compensation expense	200
Special Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Change in estimates	539
Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Change in estimates	$ 413
Restructuring Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		1,800
Nonrefundable prepaid research and development costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		900
Stock based compensation [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 900