Cymabay Therapeutics (CBAY) 10-K 16 Mar 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 29, 2020	Jun. 28, 2019
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
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	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		68,882,459
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			$ 487,988,477

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 24,869	$ 48,995
Marketable securities	166,076	129,669
Accrued interest receivable	687	304
Prepaid research and development expenses	9,910	1,670
Other prepaid expenses	1,381	924
Total current assets	202,923	181,562
Property and equipment, net	2,409	2,905
Operating lease right-of-use assets	235
Other assets	160	2,280
Total assets	205,727	186,747
Current liabilities:
Accounts payable	2,503	1,973
Accrued restructuring	3,193
Accrued research and development expenses	9,218	8,588
Other accrued liabilities	2,722	3,854
Total current liabilities	17,636	14,415
Long-term portion of operating lease liability	1,743
Other liabilities		1,914
Total liabilities	19,379	16,329
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.0001 par value: 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value: 100,000,000 shares authorized; 68,882,459 and 59,456,493 shares issued and outstanding as of December 31, 2019 and 2018, respectively	7	6
Additional paid-in capital	812,133	693,534
Accumulated other comprehensive income (loss)	80	(58)
Accumulated deficit	(625,872)	(523,064)
Total stockholders' equity	186,348	170,418
Total liabilities and stockholders' equity	$ 205,727	$ 186,747

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	68,882,459	59,456,493
Common stock, shares outstanding	68,882,459	59,456,493

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating expenses:
Research and development	$ 83,837	$ 58,124
General and administrative	19,238	14,381
Restructuring charges	5,075
Total operating expenses	108,150	72,505
Loss from operations	(108,150)	(72,505)
Other income (expense):
Interest income	5,342	3,988
Interest expense		(336)
Loss on extinguishment of debt		(407)
Other expense, net		(3,288)
Total other income (expense)	5,342	(43)
Net loss	(102,808)	(72,548)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities	138	(14)
Other comprehensive income (loss)	138	(14)
Comprehensive loss	$ (102,670)	$ (72,562)
Basic net loss per common share	$ (1.53)	$ (1.25)
Diluted net loss per common share	$ (1.53)	$ (1.26)
Weighted average common shares outstanding used to calculate basic net loss per common share	67,033,046	57,808,254
Weighted average common shares outstanding used to calculate diluted net loss per common share	67,033,046	57,838,299

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, 2017	$ 84,947	$ 4	$ 535,503	$ (44)	$ (450,516)
Balance at beginning of period (in shares) at Dec. 31, 2017		44,408,796
Issuance of common stock upon exercise of warrants, value	11,929		11,929
Issuance of common stock upon exercise of warrants (Shares)		956,845
Issuance of common stock upon exercise of stock options and incentive awards	3,571		3,571
Issuance of common stock upon exercise of stock options and incentive awards (Shares)		750,852
Stock-based compensation expense	7,013		7,013
Issuance costs of common stock, net of issuance costs, value	135,520	$ 2	135,518
Issuance of common stock, (in shares)		13,340,000
Net loss	(72,548)				(72,548)
Net unrealized gain (loss) on marketable securities	(14)			(14)
Balance at end of period at Dec. 31, 2018	170,418	$ 6	693,534	(58)	(523,064)
Balance at end of period (in shares) at Dec. 31, 2018		59,456,493
Issuance of common stock upon exercise of warrants, value	386		386
Issuance of common stock upon exercise of warrants (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

Consolidated Statement of Sto_2

Consolidated Statement of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Stock issuance cost	$ 7,254	$ 8,553

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ (102,808)	$ (72,548)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	572	105
Stock-based compensation expense	9,558	7,013
Accelerated vesting of stock-based compensation expense due to restructuring	910
Net accretion and amortization of investments in marketable securities	(2,237)	(1,945)
Non-cash interest associated with debt discount accretion		148
Loss on extinguishment of debt		407
Change in fair value of warrant liability		3,710
Gain on extinguishment of warrant liability		(422)
Accretion of tenant improvement allowance		(263)
Changes in assets and liabilities:
Receivable from collaboration		5,000
Interest receivable and other current assets	(383)	(178)
Prepaid research and development and other prepaid expenses	(8,697)	(1,386)
Other assets	2,120	(1,646)
Accounts payable	530	662
Accrued restructuring	3,193
Accrued liabilities	(669)	6,450
Accrued interest payable		(43)
Net cash used in operating activities	(97,911)	(54,936)
Investing activities
Purchases of property and equipment	(315)	(529)
Purchases of marketable securities	(290,893)	(276,382)
Proceeds from maturities of marketable securities	252,881	222,800
Proceeds from sale of marketable securities	3,980
Net cash used in investing activities	(34,347)	(54,111)
Financing activities
Proceeds from issuance of common stock, net of issuance costs	107,746	135,520
Proceeds from issuance of common stock pursuant to equity award plans	386	3,571
Proceeds from issuance of common stock upon exercise of warrants		2,550
Repayment of facility loan principal		(6,527)
Payment of fees to extinguish facility loan		(126)
Net cash provided by financing activities	108,132	134,988
Net (decrease) increase in cash and cash equivalents	(24,126)	25,941
Cash and cash equivalents at beginning of period	48,995	23,054
Cash and cash equivalents at end of period	24,869	48,995
Supplemental disclosures
Cash paid for amounts included in the measurement of lease liabilities	628
Cash paid for interest		231
Supplemental non-cash investing and financing activities
Issuance of common stock upon warrant exercises		9,379
Operating lease right-of-use assets obtained in exchange for lease liabilities	$ 152
Lessor funded lease incentives included in property and equipment		2,256
Accrued property and equipment		$ 156

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	1. Organization and Description of Business CymaBay Therapeutics, Inc. (the Company or CymaBay) is a clinical-stage biopharmaceutical company focused on developing and providing access to innovative therapies for patients with liver and other chronic diseases with high unmet medical need. The Company’s key clinical development candidate is seladelpar (MBX-8025). Liquidity The Company has incurred net operating losses and negative cash flows from operations since its inception. During the year ended December 31, 2019, the Company incurred a net loss of $102.8 million and used $97.9 million of cash in operations. At December 31, 2019, the Company had an accumulated deficit of $625.9 million. 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 More recently, in the fourth quarter of 2019, the Company terminated its ongoing clinical trials in PBC, PSC, and NASH and placed the further development of seladelpar on clinical hold pending further investigation and review of certain histological observations seen in NASH patients and pending additional discussions with the FDA. In parallel with this review, the Company also commenced a process to evaluate all potential ways to maximize stockholder value including possible mergers and business combinations, a sale of part or all of the Company’s assets, collaboration and licensing agreements, dissolution and liquidation of the Company’s assets, and/or continuing development of internal programs. As of December 31, 2019, the Company had cash, cash equivalents and marketable securities totaling $190.9 million. While the Company completes its clinical review and FDA discussions and evaluates additional ways to maximize shareholder value, cash is considered sufficient to fund the Company’s currently scaled-back operating plan into 2021. Once the Company’s future business strategy is confirmed, its future liquidity and capital resource needs could be impacted by numerous factors, including but not limited to, funding requirements associated with a merger, collaboration, or licensing arrangement and/or the incurrence of costs associated with the continued development of internal programs as well as costs to wind down current seladelpar clinical trials. The Company has historically obtained and, if needed, expects to obtain 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
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. Certain reclassifications have been made to the prior period amounts to conform to the current year presentation. “Prepaid research and development expenses” and “Other prepaid expenses”, which previously were reported as “Prepaid expenses” on the consolidated balance sheet, are now reported as separate line items. 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. The Company believes a higher level of Fair Value of Financial Instruments The Company’s financial instruments during the periods reported consist of cash and cash equivalents, marketable securities, accounts receivable, prepaid expenses, other current assets, accounts payable, 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, accounts receivable, prepaid expenses, other current assets, accounts payable, accrued expenses, and accrued interest payable approximate the related fair values due to the short maturities of these instruments. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Assets and liabilities that are measured at fair value are reported using a three-level fair value hierarchy that prioritizes the inputs used to measure fair value. This hierarchy maximizes the use of observable inputs and maximizes the use of unobservable inputs and is as follows: Level 1—Quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2—Inputs other than quoted prices in active markets that are observable for the asset or liability, either directly or indirectly. Level 3—Inputs that are significant to the fair value measurement and are unobservable (i.e. supported by little market activity), which requires the reporting entity to develop its own valuation techniques and assumptions. The following tables present the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis using the above input categories (in thousands): As of 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 Short-term investments: 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 short-term investments — 166,076 — 166,076 Total assets measured at fair value $ 18,597 $ 166,076 $ — $ 184,673 As of December 31, 2018 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 39,481 $ — $ — $ 39,481 U.S. and foreign commercial paper — 6,469 — 6,469 Total cash equivalents 39,481 6,469 — 45,950 Short-term investments: U.S. and foreign commercial paper — 51,627 — 51,627 U.S. and foreign corporate debt securities — 34,634 — 34,634 Asset-backed securities — 25,472 — 25,472 U.S. treasury securities — 17,936 — 17,936 Total short-term investments — 129,669 — 129,669 Total assets measured at fair value $ 39,481 $ 136,138 $ — $ 175,619 The Company estimates the fair value of its money market funds , corporate debt, asset backed securities, c o aper . There were no transfers between fair value measurement levels for any periods presented. Historically, the Company held a Level 3 liability associated with common stock warrants that were issued in connection with the Company’s financings completed in September and October 2013, January 2014, and August 2015. The warrants were accounted for as liabilities until either they were exercised or expired in September 2018 The following tables set forth a summary of the changes in the fair value of the Company’s liabilities measured using Level 3 inputs (in thousands): Year Ended 2019 2018 Balance, beginning of period $ — $ 6,091 Change in fair value — 3,710 Settlement of financial instruments — (9,379 ) Extinguishment of financial instruments — (422 ) Balance, end of period $ — $ — 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 The Company invests excess cash in marketable securities with high credit ratings that are classified in Level 1 and Level 2 of the fair value hierarchy. These securities consist primarily of corporate debt, commercial paper, asset-backed securities, and U.S. treasury securities and are classified as “available-for-sale.” 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, 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 Leases The Company has one lease, a non-cancelable Subsequent to the adoption of the new leasing standard on January 1, 2019, the Company recognizes a lease asset for its right to use the underlying asset and a lease liability for the corresponding lease obligation. The Company determines whether an arrangement is or contains a lease at contract inception. Operating leases are included in operating lease right-of-use right-of-use The operating lease right-of-use non-lease non-lease 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 of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of subjects and the completion of clinical trial milestones. In amortizing or accruing service fees, the Company estimates the time period over which services will be performed, enrollment of subjects, number of sites activated and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the Company’s estimate, the Company will adjust the accrued or prepaid expense balance accordingly. To date, there have been no material differences from the Company’s estimates to the amounts actually incurred. Restructuring Charges The Company recognizes restructuring charges related to reorganization plans that have been committed to by management and when , , One-time employee termination benefits are recognized in their entirety when communication has occurred and future services are not required. If future services are required, the costs are recorded ratably over the remaining period of service. Contract termination costs to be incurred over the remaining contract term without economic benefit are recorded in their entirety when the contract is canceled. 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 Employee and director stock-based compensation is measured at fair value on the grant date of the award. Compensation cost is recognized as expense on a straight-line basis over the vesting period for options and on an accelerated basis for stock options with performance conditions, net of estimated forfeitures. For stock options with performance conditions, the Company evaluates the probability of achieving performance conditions at each reporting date. The Company begins to recognize the expense when it is deemed probable that the performance conditions will be met. The Company uses the Black-Scholes option-pricing model to determine the fair value of stock option awards. The determination of fair value for stock-based awards using an option-pricing model requires management to make certain assumptions regarding subjective input variables such as expected term, dividends, volatility and risk-free rate. The Company is also required to make estimates as to the probability of achieving the specific performance criteria. If actual results are not consistent with the Company’s assumptions and judgments used in making these estimates, the Company may be required to increase or decrease compensation expense, which could be material to the Company’s results of operations. Equity awards granted to non-employees 2018-07, Compensation – Stock Compensation Common Stock Warrant Liabilities Historically, the Company’s outstanding common stock warrants issued in connection with certain equity and debt financings that occurred in 2013 through 2015 were classified as liabilities in the accompanying consolidated balance sheets because of certain contractual terms that preclude equity classification. All outstanding warrants related to these financings had been exercised or had expired by September 30, 2018. Upon expiration, the remaining fair value of the liability was extinguished and credited to other (expense) income, net in the Company’s consolidated statement of operations. Prior to expiration, the Company estimated the fair value of common stock warrants at each reporting period until the exercise of the warrants, at which time the liability was revalued and reclassified to stockholders’ equity. The determination of fair value of these common stock warrants required management to make certain assumptions regarding subjective input variables such as timing, probability and valuation impact of certain potential strategic events, expected term, dividends, expected volatility and risk-free interest rates. 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. There was no interest or penalties related to income tax reserves during the years ended December 31, 2019 or 2018. 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 and common stock warrants, if dilutive. The calculation of diluted loss per share also requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the common stock warrants and the presumed exercise of such securities are dilutive to earnings (loss) per share for the period, adjustments to net income or net loss used in the calculation are required to remove the change in fair value of the common stock warrant liability for the period. Likewise, adjustments to the denominator are required to reflect the related dilutive shares. In all periods presented, the Company’s outstanding stock options were excluded from the calculation of 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, 2019 2018 Numerator: Net loss allocated to common stock—basic $ (102,808 ) $ (72,548 ) Adjustment for revaluation and extinguishment of common stock warrants — (422 ) Net loss allocated to common stock—diluted $ (102,808 ) $ (72,970 ) Denominator: Weighted average number of common stock shares outstanding—basic 67,033,046 57,808,254 Dilutive securities: Common stock warrants — 30,045 Weighted average number of common stock shares outstanding—diluted 67,033,046 57,838,299 Net loss per share—basic $ (1.53 ) $ (1.25 ) Net loss per share—diluted $ (1.53 ) $ (1.26 ) 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 2019 2018 Common stock options 6,727 5,593 Incentive awards 101 130 Total 6,828 5,723 Recently Adopted Accounting Pronouncements ASU 2016-02 2018-11 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). right-of-use O 2018-11, Leases (Topic 842) Targeted Improvements The Company adopted this standard on January 1, 2019 using the modified retrospective approach and elected the package of practical expedients permitted under transition guidance, which allowed the Company to carry forward its historical assessments of: 1) whether contracts are or contain leases, 2) lease classification and 3) initial direct costs. The Company did not elect the practical expedient allowing the use-of-hindsight The adoption of this standard resulted in the recognition of a ROU asset and lease liabilities of $0.2 million and $2.5 million, respectively, and the derecognition of the deferred rent balance of $2.3 million as of January 1, 2019. The adoption of the standard had no impact on the Company’s condensed consolidated statements of operations and comprehensive loss or to its cash flows from or used in operating, financing, or investing activities on its condensed consolidated statements of cash flows. No cumulative-effect adjustment within accumulated deficit was required to be recorded as a result of adopting this standard. ASU 2018-08 On January 1, 2019 the Company adopted ASU No. 2018-08, Not-For-Profit Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made 2018-08), 2018-08 Not-for-Profit Entities ASU 2018-07 On January 1, 2019, the Company adopted ASU 2018-07, Compensation – Stock Compensation non-employees – non-employees non-employees Recently Issued 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, 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 – Changes to the Disclosure Requirements for Fair Value Measurement ASU In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments available-for-sale securities be recorded as an allowance through net income rather than reducing the carrying amount under the current, other-than-temporary-impairment model. In November 2019, FASB issued ASU No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842)

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Marketable Securities	3. Marketable Securities Marketable available-for-sale Amortized Gross Gross Estimated As of December 31, 2019: Cash equivalents: Money market funds $ 18,597 $ — $ — $ 18,597 U.S. and foreign commercial paper — — — — 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 Amortized Gross Gross Estimated As of December 31, 2018: Cash equivalents: Money market funds $ 39,481 $ — $ — $ 39,481 U.S. and foreign commercial paper 6,469 — — 6,469 Total cash equivalents 45,950 — — 45,950 Short-term investments: U.S. and foreign commercial paper 51,627 — — 51,627 U.S. and foreign corporate debt securities 34,668 — (34 ) 34,634 Asset-backed securities 25,494 — (22 ) 25,472 U.S. treasury securities 17,938 — (2 ) 17,936 Total short-term investments 129,727 — (58 ) 129,669 Total marketable securities $ 179,677 $ — $ (58 ) $ 175,619 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. As of December 31, 2019 and 2018, the remaining contractual maturities of the Company’s commercial paper, corporate debt securities, asset-backed securities, and U.S. treasury securities were less than 1 year. There were no realized gains and losses for the years ended December 31, 2019 and 2018. None of these investments have been in a continuous unrealized loss position for more than 12 months as of December 31, 2019 and 2018. 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, 2019
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, 2019 2018 Leasehold improvements $ 2,430 $ 2,417 Office and computer equipment 290 214 Purchased software 44 44 Furniture and fixtures 430 360 Total 3,194 3,035 Less accumulated depreciation and amortization (785 ) (130 ) Property and equipment, net $ 2,409 $ 2,905 Depreciation expense for the years ended December 31, 2019 and 2018 was approximately $0.8 million and $0.1 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. Other accrued liabilities consist of the following (in thousands): December 31, 2019 2018 Accrued compensation $ 2,013 $ 2,759 Operating lease liability 407 — Accrued professional fees and other 302 670 Deferred rent — 425 Other accr u i s $ 2,722 $ 3,854

Collaboration and License Agree

Collaboration and License Agreements	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreements	5. Collaboration and License Agreements Kowa Pharmaceuticals America, Inc. On December 30, 2016, the Company entered into a license agreement with Kowa. Pursuant to the license agreement, the Company granted to Kowa an exclusive license, and right to sublicense, certain patent rights and technology related to arhalofenate. Under the license agreement, Kowa agreed to pay the Company a non-refundable million upon contract execution. Kowa also agreed to pay the million upon initiation of a study evaluating the pharmacokinetics of arhalofenate in subjects with renal impairment, which occurred during the quarter ended December 31, 2017 and payment was received in January 2018. Additional payments of up to million could have been earned based upon the achievement of other specific development and sales milestones. On October 24, 2018, the Company received a notice of Kowa’s intent to terminate the license agreement for the development of arhalofenate. The termination was effective on January 22, 2019. As a result of the termination, the rights licensed to Kowa through the agreement revert to the Company on the termination date and the Company is no longer eligible to receive additional milestone payments or royalties from Kowa. As of the time of the receipt of Kowa’s notice to terminate, all remaining variable consideration under the license agreement had been fully constrained and all performance obligations had been satisfied. 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 right to grant sublicenses to third parties to make, use and sell such PPAR d Products. Under the terms of the agreement, the Company has full control and responsibility over the research, development and registration of any PPAR d Products and is required to use diligent efforts to conduct all such activities. Janssen NV has the sole responsibility for the preparation, filing, prosecution, maintenance of, and defense of the patents with respect to, the PPAR d Products. Janssen NV has a right of first negotiation under the agreement to license PPAR d Products from the Company in the event that the Company elects to seek a third party corporate partner for the research, development, promotion, and/or commercialization of such PPAR d Products. Under the terms of the agreement Janssen NV is entitled to receive up to 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 31, 2019 and 2018. In June 2010, the Company entered into development and license agreements with Janssen Pharmaceuticals, Inc. (Janssen), a subsidiary of Johnson and Johnson, to further develop and discover undisclosed metabolic disease target agonists for the treatment of Type 2 diabetes and other disorders and received a one-time nonrefundable technology access fee related to the agreements. The Company received a termination notice from Janssen, effectively ending these development and licensing agreements in early April 2015. In December 2015, 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 entered into a license agreement with DiaTex, Inc. (DiaTex) relating to products containing halofenate, its enantiomers, derivatives, and analogs (the licensed products). The license agreement provides that DiaTex and the Company are joint owners of all of the patents and patent applications covering the licensed products and methods of producing or using such compounds, as well as certain other know-how sub-license

Term Loan

Term Loan	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Facility Loans	6. Term Loan On August 7, 2015, the Company entered into a Loan and Security Agreement (the 2015 Term Loan Facility) pursuant to which it refinanced its existing term loan facility for an aggregate amount of up to $15.0 million. On June 4, 2018, the Company repaid in full the outstanding balance of the 2015 Term Loan Facility of $4.2 million plus a final fee of $0.7 million and a prepayment penalty of $0.1 million. In conjunction with this prepayment, the Company recorded a $0.4 million loss on early of extinguishment of this debt.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. 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, 2019 and 2018. 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.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	8. 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, 2019 the Company’s lease portfolio had a weighted average remaining term of 4.1 years, with an option to extend for an additional 5 years. The lease requires monthly lease payments that are subject to annual increases throughout the lease term. The optional period has not been considered in the determination of the right-of-use The Company cannot determine the implicit rate in its lease, and therefore the Company uses its incremental borrowing rate rate For the years ended December 31, 2019 and 2018, the Company incurred $0.5 million and $0.4 million, respectively, of lease costs included in operating expenses in the condensed consolidated statements of income and comprehensive income in relation to its operating lease, a portion of which was variable rent expense and not included within the measurement of the Company’s operating ROU assets and lease liabilities. The variable rent expense consists primarily of the Company’s proportionate share of operating expenses, property taxes, and insurance and is classified as lease expense due to the Company’s election to not separate lease and non-lease right-of-use - . As of December 31, 2019, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Operating Year ending December 31, 2020 647 2021 667 2022 686 2023 707 2024 30 Total undiscounted future minimum lease payments $ 2,737 Less: Imputed interest 587 Total operating lease liability $ 2,150 Less: Current portion of operating lease liability (included in other accrued liabilities) 407 Long-term portion of operating lease liability $ 1,743

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity The Company is authorized to issue 10,000,000 shares of preferred stock as of December 31, 2019 and 2018, respectively. The Company is authorized to issue 100,000,000 shares of common stock as of December 31, 2019 and 2018, respectively. As of December 31, 2019 and 2018, the Company had reserved shares of authorized but unissued common stock as follows: December 31, 2019 2018 Equity incentive plan 9,143,863 6,991,570 Total reserved shares of common stock 9,143,863 6,991,570 Sale of Common Stock On February 1, 2018, pursuant to a $200.0 million shelf registration statement on Form S-3, On December 28, 2018, the Company filed a $200.0 million shelf registration statement on Form S-3 On March 8, 2019, pursuant to a shelf registration statement on Form S-3, Common Stock Warrants In connection with a 2013 financing and the Company’s private placement of common five-year seven-year ten-year The 2013 financing warrants contain anti-dilution provisions that are contingent on the occurrence of a major transaction which precludes them from being indexed to the Company’s common stock and also do not meet other criteria for equity classification. Such provisions could also result in the settlement of the 2013 financing warrants for more shares of common stock than the Company has authorized. Due to these provisions, the Company is required to account for the 2013 financing warrants and the lender warrants as liabilities at fair value. Accordingly, the Company recorded the warrants at fair value upon issuance and remeasured them at fair value at each balance sheet date until they were exercised or expired. During the year ended December 31, 2018, the Company’s warrants were remeasured using Level 3 inputs involving a Black-Scholes option-pricing model, the inputs for which include: the exercise price of the warrants; the market price of the underlying common shares; a risk-free interest rate based on the rates for U.S. treasury zero-coupon Significant The resulting increase in warrant liability fair value of $3.7 million for the year ended December 31, 2018 was recorded as revaluation losses in other (expense) income, net in the Company’s consolidated statement of operations and comprehensive loss. During the year ended December 31, 2018, 443,505 warrants were exercised for cash proceeds of $2.6 million and 938,300 warrants were cashless exercised for 513,340 shares of the Company’s common stock. On September 30, 2018, 79,150 of remaining unexercised warrants expired, resulting in the recognition of a $0.4 million gain on extinguishment of the related warrant liability. As of December 31, 2019 and 2018, no warrants were outstanding.

Stock Plan and Stock-Based Comp

Stock Plan and Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock Plans and Stock-Based Compensation	10. Stock Plan and Stock-Based Compensation Stock Plan 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. The share reserve under the 2013 Plan will automatically increase on January 1 st st st Stock Plan Activity As of December 31, 2019, there were 2,315,727 shares available for grant under the 2013 Plan. In accordance with the provisions of the 2013 Plan, the Board of Directors reduced the automatic share increase in the share reserve on January 1, 2020 to zero shares. 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 (in Outstanding as of December 31, 2018 5,593,132 $ 7.68 Options granted 2,775,360 8.25 Options exercised (223,631 ) 1.67 Options forfeited (1,127,078 ) 8.63 Options expired (291,088 ) 9.42 Outstanding as of December 31, 2019 6,726,695 $ 7.88 $ 7.39 $ 369 Vested and expected to vest as of December 31, 2019 6,726,695 7.88 7.39 $ 369 Exercisable as of December 31, 2019 3,769,835 $ 6.87 $ 6.47 $ 328 The total intrinsic value of options exercised was $0.4 million and $4.9 million, for the years ended December 31, 2019 and 2018, respectively. Vested and Unvested Awards The total fair value of options vested was $9.9 million and $7.0 million for the years ended December 31, 2019 and 2018, respectively. As of December 31, 2019, unamortized employee and non-employee m 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 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 stock - Options Granted to Nonemployees The Company has issued options to purchase shares of common stock to certain scientific advisors and consultants. The stock options have various exercise prices, a term of ten years, and vest over periods up to forty-eight months No options were in 2019 and the Company granted 8 shares of common stock remained 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 December 31, 2019 2018 Research and development $ 4,361 $ 2,760 General and administrative 5,197 4,253 Restructuring charges 910 — Total stock-based compensation expense $ 10,468 $ 7,013 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 December 31, 2019 2018 Expected term (in years) 6.2 6.2 Expected volatility 76 % 77 % Risk-free interest rate 2.13 % 2.62 % Expected dividend yield — % — % Weighted-average grant date fair value per share $ 5.60 $ 8.14 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, 2019 and 2018, the Company has opted 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 limited trading history for its common stock, the expected stock price volatility for the Company’s common stock was estimated by considering the volatility rates of similar publicly traded peer entities within the life sciences industry. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available. 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, 2019
Postemployment Benefits [Abstract]
401(k) Plan	11. 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, 2019 and 2018.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	12. 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 2019 2018 Deferred tax assets: Federal and state net operating loss carryforwards $ 107,213 $ 85,571 Federal and state research and development tax credit carryforwards 25,661 18,590 Capitalized research and development 4,725 10,466 Stock based compensation 3,562 2,848 Other 1,199 1,499 Total deferred tax assets 142,360 118,974 Deferred tax liabilities: Depreciation and amortization (372 ) (622 ) Other (49 ) — Total deferred tax liabilities (421 ) (622 ) Valuation allowance (141,939 ) (118,352 ) 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 $23.6 million and $29.5 million during the years ended December 31, 2019 and 2018, respectively. The following is a reconciliation of the expected statutory federal income tax provision to the actual income tax provision (in thousands): December 31 2019 2018 Income tax benefit at federal statutory tax rate $ (21,589 ) $ (15,235 ) Change in valuation allowance 23,587 29,501 State income taxes, net of federal benefit 3,810 (10,112 ) Research credits (6,555 ) (4,717 ) Other 747 563 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 As of December 31, 2019, the Company h ad had million. If not utilized, the federal net operating losses for the years beginning before January 1, 2018 of $255.7 million , and the federal net operating losses for the tax years beginning after January 1, 2018 of $180.2 million will be carried forward indefinitely (subject to certain utilization limitations). The state net operating loss carryforwards will expire beginning in 2028 through 2039. The federal research and development and federal orphan drug tax credit carryforwards will expire beginning in 2020 through 2039, and the state tax credit will carry forward indefinitely. Interest and penalties for the years ended December 31, 2019 and 2018 were not material. The following table summarizes activity related to the Company’s gross unrecognized tax benefits (in thousands): Total Balances as of December 31, 2017 $ 3,295 Increases related to prior year tax positions 6 Increases related to 2018 tax positions 1,283 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 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, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Related Activities Disclosure	13. 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 25, 2019 announcement that it had halted clinical development of seladelpar. As of December 31, 2019, the restructuring liability is included in current liabilities on the consolidated balance sheet. The Company incurred aggregate restructuring charges of approximately $5.1 million for the year ended December 31, 2019. Restructuring charges incurred under this plan primarily consisted of employee termination benefits and contract termination costs primarily 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 during the year ended December 31, 2019 (in thousands): Termination Contract Total Balances as of January 1, 2019 $ — $ — $ — Restructuring charges 2,912 413 3,325 Reductions for cash payments (132 ) — (132 ) Balances as of December 31, 2019 $ 2,780 $ 413 $ 3,193 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.

Organization and Description _2

Organization and Description of Business (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Liquidity	Liquidity The Company has incurred net operating losses and negative cash flows from operations since its inception. During the year ended December 31, 2019, the Company incurred a net loss of $102.8 million and used $97.9 million of cash in operations. At December 31, 2019, the Company had an accumulated deficit of $625.9 million. 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 More recently, in the fourth quarter of 2019, the Company terminated its ongoing clinical trials in PBC, PSC, and NASH and placed the further development of seladelpar on clinical hold pending further investigation and review of certain histological observations seen in NASH patients and pending additional discussions with the FDA. In parallel with this review, the Company also commenced a process to evaluate all potential ways to maximize stockholder value including possible mergers and business combinations, a sale of part or all of the Company’s assets, collaboration and licensing agreements, dissolution and liquidation of the Company’s assets, and/or continuing development of internal programs. As of December 31, 2019, the Company had cash, cash equivalents and marketable securities totaling $190.9 million. While the Company completes its clinical review and FDA discussions and evaluates additional ways to maximize shareholder value, cash is considered sufficient to fund the Company’s currently scaled-back operating plan into 2021. Once the Company’s future business strategy is confirmed, its future liquidity and capital resource needs could be impacted by numerous factors, including but not limited to, funding requirements associated with a merger, collaboration, or licensing arrangement and/or the incurrence of costs associated with the continued development of internal programs as well as costs to wind down current seladelpar clinical trials. The Company has historically obtained and, if needed, expects to obtain 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.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company’s financial instruments during the periods reported consist of cash and cash equivalents, marketable securities, accounts receivable, prepaid expenses, other current assets, accounts payable, 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, accounts receivable, prepaid expenses, other current assets, accounts payable, accrued expenses, and accrued interest payable approximate the related fair values due to the short maturities of these instruments. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Assets and liabilities that are measured at fair value are reported using a three-level fair value hierarchy that prioritizes the inputs used to measure fair value. This hierarchy maximizes the use of observable inputs and maximizes the use of unobservable inputs and is as follows: Level 1—Quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2—Inputs other than quoted prices in active markets that are observable for the asset or liability, either directly or indirectly. Level 3—Inputs that are significant to the fair value measurement and are unobservable (i.e. supported by little market activity), which requires the reporting entity to develop its own valuation techniques and assumptions. The following tables present the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis using the above input categories (in thousands): As of 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 Short-term investments: 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 short-term investments — 166,076 — 166,076 Total assets measured at fair value $ 18,597 $ 166,076 $ — $ 184,673 As of December 31, 2018 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 39,481 $ — $ — $ 39,481 U.S. and foreign commercial paper — 6,469 — 6,469 Total cash equivalents 39,481 6,469 — 45,950 Short-term investments: U.S. and foreign commercial paper — 51,627 — 51,627 U.S. and foreign corporate debt securities — 34,634 — 34,634 Asset-backed securities — 25,472 — 25,472 U.S. treasury securities — 17,936 — 17,936 Total short-term investments — 129,669 — 129,669 Total assets measured at fair value $ 39,481 $ 136,138 $ — $ 175,619 The Company estimates the fair value of its money market funds , corporate debt, asset backed securities, c o aper . There were no transfers between fair value measurement levels for any periods presented. Historically, the Company held a Level 3 liability associated with common stock warrants that were issued in connection with the Company’s financings completed in September and October 2013, January 2014, and August 2015. The warrants were accounted for as liabilities until either they were exercised or expired in September 2018 The following tables set forth a summary of the changes in the fair value of the Company’s liabilities measured using Level 3 inputs (in thousands): Year Ended 2019 2018 Balance, beginning of period $ — $ 6,091 Change in fair value — 3,710 Settlement of financial instruments — (9,379 ) Extinguishment of financial instruments — (422 ) Balance, end of period $ — $ — 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 The Company invests excess cash in marketable securities with high credit ratings that are classified in Level 1 and Level 2 of the fair value hierarchy. These securities consist primarily of corporate debt, commercial paper, asset-backed securities, and U.S. treasury securities and are classified as “available-for-sale.” 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, 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 Subsequent to the adoption of the new leasing standard on January 1, 2019, the Company recognizes a lease asset for its right to use the underlying asset and a lease liability for the corresponding lease obligation. The Company determines whether an arrangement is or contains a lease at contract inception. Operating leases are included in operating lease right-of-use right-of-use The operating lease right-of-use non-lease non-lease
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 of the expense. Payments under some of these contracts depend on factors such as the successful enrollment of subjects and the completion of clinical trial milestones. In amortizing or accruing service fees, the Company estimates the time period over which services will be performed, enrollment of subjects, number of sites activated and the level of effort to be expended in each period. If the actual timing of the performance of services or the level of effort varies from the Company’s estimate, the Company will adjust the accrued or prepaid expense balance accordingly. To date, there have been no material differences from the Company’s estimates to the amounts actually incurred.
Restructuring Charges	Restructuring Charges The Company recognizes restructuring charges related to reorganization plans that have been committed to by management and when , , One-time employee termination benefits are recognized in their entirety when communication has occurred and future services are not required. If future services are required, the costs are recorded ratably over the remaining period of service. Contract termination costs to be incurred over the remaining contract term without economic benefit are recorded in their entirety when the contract is canceled. 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 Employee and director stock-based compensation is measured at fair value on the grant date of the award. Compensation cost is recognized as expense on a straight-line basis over the vesting period for options and on an accelerated basis for stock options with performance conditions, net of estimated forfeitures. For stock options with performance conditions, the Company evaluates the probability of achieving performance conditions at each reporting date. The Company begins to recognize the expense when it is deemed probable that the performance conditions will be met. The Company uses the Black-Scholes option-pricing model to determine the fair value of stock option awards. The determination of fair value for stock-based awards using an option-pricing model requires management to make certain assumptions regarding subjective input variables such as expected term, dividends, volatility and risk-free rate. The Company is also required to make estimates as to the probability of achieving the specific performance criteria. If actual results are not consistent with the Company’s assumptions and judgments used in making these estimates, the Company may be required to increase or decrease compensation expense, which could be material to the Company’s results of operations. non-employees 2018-07, Compensation – Stock Compensation
Common Stock Warrant Liabilities	Common Stock Warrant Liabilities Historically, the Company’s outstanding common stock warrants issued in connection with certain equity and debt financings that occurred in 2013 through 2015 were classified as liabilities in the accompanying consolidated balance sheets because of certain contractual terms that preclude equity classification. All outstanding warrants related to these financings had been exercised or had expired by September 30, 2018. Upon expiration, the remaining fair value of the liability was extinguished and credited to other (expense) income, net in the Company’s consolidated statement of operations. Prior to expiration, the Company estimated the fair value of common stock warrants at each reporting period until the exercise of the warrants, at which time the liability was revalued and reclassified to stockholders’ equity. The determination of fair value of these common stock warrants required management to make certain assumptions regarding subjective input variables such as timing, probability and valuation impact of certain potential strategic events, expected term, dividends, expected volatility and risk-free interest rates.
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. There was no interest or penalties related to income tax reserves during the years ended December 31, 2019 or 2018.
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 and common stock warrants, if dilutive. The calculation of diluted loss per share also requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of the common stock warrants and the presumed exercise of such securities are dilutive to earnings (loss) per share for the period, adjustments to net income or net loss used in the calculation are required to remove the change in fair value of the common stock warrant liability for the period. Likewise, adjustments to the denominator are required to reflect the related dilutive shares. In all periods presented, the Company’s outstanding stock options were excluded from the calculation of 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, 2019 2018 Numerator: Net loss allocated to common stock—basic $ (102,808 ) $ (72,548 ) Adjustment for revaluation and extinguishment of common stock warrants — (422 ) Net loss allocated to common stock—diluted $ (102,808 ) $ (72,970 ) Denominator: Weighted average number of common stock shares outstanding—basic 67,033,046 57,808,254 Dilutive securities: Common stock warrants — 30,045 Weighted average number of common stock shares outstanding—diluted 67,033,046 57,838,299 Net loss per share—basic $ (1.53 ) $ (1.25 ) Net loss per share—diluted $ (1.53 ) $ (1.26 ) 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 2019 2018 Common stock options 6,727 5,593 Incentive awards 101 130 Total 6,828 5,723
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements ASU 2016-02 2018-11 In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). right-of-use O 2018-11, Leases (Topic 842) Targeted Improvements The Company adopted this standard on January 1, 2019 using the modified retrospective approach and elected the package of practical expedients permitted under transition guidance, which allowed the Company to carry forward its historical assessments of: 1) whether contracts are or contain leases, 2) lease classification and 3) initial direct costs. The Company did not elect the practical expedient allowing the use-of-hindsight ASU 2018-08 On January 1, 2019 the Company adopted ASU No. 2018-08, Not-For-Profit Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made 2018-08), 2018-08 Not-for-Profit Entities ASU 2018-07 On January 1, 2019, the Company adopted ASU 2018-07, Compensation – Stock Compensation non-employees – non-employees non-employees Recently Issued 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, 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 – Changes to the Disclosure Requirements for Fair Value Measurement ASU In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments available-for-sale securities be recorded as an allowance through net income rather than reducing the carrying amount under the current, other-than-temporary-impairment model. In November 2019, FASB issued ASU No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815) and Leases (Topic 842)

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis	The following tables present the fair value of the Company’s financial assets and liabilities measured at fair value on a recurring basis using the above input categories (in thousands): As of 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 Short-term investments: 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 short-term investments — 166,076 — 166,076 Total assets measured at fair value $ 18,597 $ 166,076 $ — $ 184,673 As of December 31, 2018 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 39,481 $ — $ — $ 39,481 U.S. and foreign commercial paper — 6,469 — 6,469 Total cash equivalents 39,481 6,469 — 45,950 Short-term investments: U.S. and foreign commercial paper — 51,627 — 51,627 U.S. and foreign corporate debt securities — 34,634 — 34,634 Asset-backed securities — 25,472 — 25,472 U.S. treasury securities — 17,936 — 17,936 Total short-term investments — 129,669 — 129,669 Total assets measured at fair value $ 39,481 $ 136,138 $ — $ 175,619
Schedule of Changes in Fair Value of Liabilities	The following tables set forth a summary of the changes in the fair value of the Company’s liabilities measured using Level 3 inputs (in thousands): Year Ended 2019 2018 Balance, beginning of period $ — $ 6,091 Change in fair value — 3,710 Settlement of financial instruments — (9,379 ) Extinguishment of financial instruments — (422 ) Balance, end of period $ — $ —
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, 2019 2018 Numerator: Net loss allocated to common stock—basic $ (102,808 ) $ (72,548 ) Adjustment for revaluation and extinguishment of common stock warrants — (422 ) Net loss allocated to common stock—diluted $ (102,808 ) $ (72,970 ) Denominator: Weighted average number of common stock shares outstanding—basic 67,033,046 57,808,254 Dilutive securities: Common stock warrants — 30,045 Weighted average number of common stock shares outstanding—diluted 67,033,046 57,838,299 Net loss per share—basic $ (1.53 ) $ (1.25 ) Net loss per share—diluted $ (1.53 ) $ (1.26 )
Anti-Dilutive Securities Excluded from the Computation of 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, 2019 2018 Numerator: Net loss allocated to common stock—basic $ (102,808 ) $ (72,548 ) Adjustment for revaluation and extinguishment of common stock warrants — (422 ) Net loss allocated to common stock—diluted $ (102,808 ) $ (72,970 ) Denominator: Weighted average number of common stock shares outstanding—basic 67,033,046 57,808,254 Dilutive securities: Common stock warrants — 30,045 Weighted average number of common stock shares outstanding—diluted 67,033,046 57,838,299 Net loss per share—basic $ (1.53 ) $ (1.25 ) Net loss per share—diluted $ (1.53 ) $ (1.26 ) 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 2019 2018 Common stock options 6,727 5,593 Incentive awards 101 130 Total 6,828 5,723

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Marketable Available-for-Sale Securities	Marketable available-for-sale Amortized Gross Gross Estimated As of December 31, 2019: Cash equivalents: Money market funds $ 18,597 $ — $ — $ 18,597 U.S. and foreign commercial paper — — — — 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 Amortized Gross Gross Estimated As of December 31, 2018: Cash equivalents: Money market funds $ 39,481 $ — $ — $ 39,481 U.S. and foreign commercial paper 6,469 — — 6,469 Total cash equivalents 45,950 — — 45,950 Short-term investments: U.S. and foreign commercial paper 51,627 — — 51,627 U.S. and foreign corporate debt securities 34,668 — (34 ) 34,634 Asset-backed securities 25,494 — (22 ) 25,472 U.S. treasury securities 17,938 — (2 ) 17,936 Total short-term investments 129,727 — (58 ) 129,669 Total marketable securities $ 179,677 $ — $ (58 ) $ 175,619

Certain Balance Sheet Items (Ta

Certain Balance Sheet Items (Tables)	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Property and Equipment	Property and equipment consist of the following (in thousands): December 31, 2019 2018 Leasehold improvements $ 2,430 $ 2,417 Office and computer equipment 290 214 Purchased software 44 44 Furniture and fixtures 430 360 Total 3,194 3,035 Less accumulated depreciation and amortization (785 ) (130 ) Property and equipment, net $ 2,409 $ 2,905
Other Accrued Liabilities	Depreciation expense for the years ended December 31, 2019 and 2018 was approximately $0.8 million and $0.1 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. Other accrued liabilities consist of the following (in thousands): December 31, 2019 2018 Accrued compensation $ 2,013 $ 2,759 Operating lease liability 407 — Accrued professional fees and other 302 670 Deferred rent — 425 Other accr u i s $ 2,722 $ 3,854

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Summary of Maturities of Operating Lease Liabilities	As of December 31, 2019, the maturities of the Company’s operating lease liabilities were as follows (in thousands): Operating Year ending December 31, 2020 647 2021 667 2022 686 2023 707 2024 30 Total undiscounted future minimum lease payments $ 2,737 Less: Imputed interest 587 Total operating lease liability $ 2,150 Less: Current portion of operating lease liability (included in other accrued liabilities) 407 Long-term portion of operating lease liability $ 1,743

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Reserved Shares of Authorized but Unissued Common Stock	As of December 31, 2019 and 2018, the Company had reserved shares of authorized but unissued common stock as follows: December 31, 2019 2018 Equity incentive plan 9,143,863 6,991,570 Total reserved shares of common stock 9,143,863 6,991,570

Stock Plan and Stock-Based Co_2

Stock Plan and Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
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 (in Outstanding as of December 31, 2018 5,593,132 $ 7.68 Options granted 2,775,360 8.25 Options exercised (223,631 ) 1.67 Options forfeited (1,127,078 ) 8.63 Options expired (291,088 ) 9.42 Outstanding as of December 31, 2019 6,726,695 $ 7.88 $ 7.39 $ 369 Vested and expected to vest as of December 31, 2019 6,726,695 7.88 7.39 $ 369 Exercisable as of December 31, 2019 3,769,835 $ 6.87 $ 6.47 $ 328
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 December 31, 2019 2018 Research and development $ 4,361 $ 2,760 General and administrative 5,197 4,253 Restructuring charges 910 — Total stock-based compensation expense $ 10,468 $ 7,013
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 December 31, 2019 2018 Expected term (in years) 6.2 6.2 Expected volatility 76 % 77 % Risk-free interest rate 2.13 % 2.62 % Expected dividend yield — % — % Weighted-average grant date fair value per share $ 5.60 $ 8.14

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
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 2019 2018 Deferred tax assets: Federal and state net operating loss carryforwards $ 107,213 $ 85,571 Federal and state research and development tax credit carryforwards 25,661 18,590 Capitalized research and development 4,725 10,466 Stock based compensation 3,562 2,848 Other 1,199 1,499 Total deferred tax assets 142,360 118,974 Deferred tax liabilities: Depreciation and amortization (372 ) (622 ) Other (49 ) — Total deferred tax liabilities (421 ) (622 ) Valuation allowance (141,939 ) (118,352 ) Net deferred tax assets $ — $ —
Summary of Reconciliation of Expected Statutory Federal Income Tax Provision to Actual Income Tax Provision	The following is a reconciliation of the expected statutory federal income tax provision to the actual income tax provision (in thousands): December 31 2019 2018 Income tax benefit at federal statutory tax rate $ (21,589 ) $ (15,235 ) Change in valuation allowance 23,587 29,501 State income taxes, net of federal benefit 3,810 (10,112 ) Research credits (6,555 ) (4,717 ) Other 747 563 Income tax (benefit) expense $ — $ —
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, 2017 $ 3,295 Increases related to prior year tax positions 6 Increases related to 2018 tax positions 1,283 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

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2019
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 during the year ended December 31, 2019 (in thousands): Termination Contract Total Balances as of January 1, 2019 $ — $ — $ — Restructuring charges 2,912 413 3,325 Reductions for cash payments (132 ) — (132 ) Balances as of December 31, 2019 $ 2,780 $ 413 $ 3,193

Organization and Description _3

Organization and Description of Business - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Segment	Dec. 31, 2018USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments | Segment	1
Net loss	$ (102,808)	$ (72,548)
Cash flows from operating activities	(97,911)	(54,936)
Accumulated deficit	(625,872)	$ (523,064)
Cash and cash equivalents and marketable securities	$ 190,900

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, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 184,673
Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	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	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	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	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	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	39,788
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	18,457
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	18,597	$ 39,481
Level 1 [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	18,597	39,481
Level 1 [Member] | Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	18,597	39,481
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	166,076	136,138
Level 2 [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		6,469
Level 2 [Member] | Cash Equivalents [Member] | U.S. and Foreign Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		6,469
Level 2 [Member] | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	166,076	129,669
Level 2 [Member] | Short-term Investments [Member] | U.S. and Foreign Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	51,102	51,627
Level 2 [Member] | Short-term Investments [Member] | U.S. and Foreign Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	56,729	34,634
Level 2 [Member] | Short-term Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	39,788	25,472
Level 2 [Member] | Short-term Investments [Member] | U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 18,457	17,936
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		175,619
Level 3 [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		45,950
Level 3 [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		39,481
Level 3 [Member] | Cash Equivalents [Member] | U.S. and Foreign Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		6,469
Level 3 [Member] | Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		129,669
Level 3 [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		51,627
Level 3 [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		34,634
Level 3 [Member] | Short-term Investments [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value		25,472
Level 3 [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		$ 17,936

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Product Information [Line Items]
Warrants exercise or expiration period		Sep. 30, 2018
Cash and cash equivalents, maturity description		90 days or less
Interest or penalties related to income taxes		$ 0	$ 0	$ 0
ROU assets		235
Lease liabilities		$ 2,150
ASU 2018-08 [Member]
Product Information [Line Items]
ROU assets	$ 200
Lease liabilities	2,500
Derecognition of the deferred rent	$ 2,300
Maximum [Member]
Product Information [Line Items]
Short-term contractual maturities		1 year
Property and equipment, estimated useful lives		7 years
Minimum [Member]
Product Information [Line Items]
Long-term contractual maturities		1 year
Property and equipment, estimated useful lives		3 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Changes in Fair Value of Liabilities (Detail) - Level 3 [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Balance, beginning of period	$ 6,091
Change in fair value	3,710
Settlement of financial instruments	(9,379)
Extinguishment of financial instruments	$ (422)

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net loss allocated to common stock—basic	$ (102,808)	$ (72,548)
Adjustment for revaluation and extinguishment of common stock warrants		(422)
Net loss allocated to common stock—diluted	$ (102,808)	$ (72,970)
Denominator:
Weighted average number of common stock shares outstanding - basic	67,033,046	57,808,254
Dilutive securities:
Common stock warrants		30,045
Weighted average number of common stock shares outstanding - diluted	67,033,046	57,838,299
Net loss per share—basic	$ (1.53)	$ (1.25)
Net loss per share—diluted	$ (1.53)	$ (1.26)

Summary of Significant Accoun_7

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, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted loss per share	6,828	5,723
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	6,727	5,593
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	130

Marketable Securities - Marketa

Marketable Securities - Marketable Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value	$ 166,076	$ 129,669
Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,597	45,950
Estimated Fair Value	18,597	45,950
Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,597	39,481
Estimated Fair Value	18,597	39,481
Cash and Cash Equivalents [Member] | U.S. and Foreign Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		6,469
Estimated Fair Value		6,469
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	165,996	129,727
Gross Unrealized Gains	80
Gross Unrealized Losses		(58)
Estimated Fair Value	166,076	129,669
Short-term Investments [Member] | U.S. and Foreign Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	51,102	51,627
Estimated Fair Value	51,102	51,627
Short-term Investments [Member] | U.S. and Foreign Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	56,691	34,668
Gross Unrealized Gains	38
Gross Unrealized Losses		(34)
Estimated Fair Value	56,729	34,634
Short-term Investments [Member] | Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	39,756	25,494
Gross Unrealized Gains	33
Gross Unrealized Losses		(22)
Estimated Fair Value	39,789	25,472
Short-term Investments [Member] | U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	18,447	17,938
Gross Unrealized Gains	9
Gross Unrealized Losses		(2)
Estimated Fair Value	18,456	17,936
Maketable Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	184,593	179,677
Gross Unrealized Gains	80
Gross Unrealized Losses		(58)
Estimated Fair Value	$ 184,673	$ 175,619

Marketable Securities - Additio

Marketable Securities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
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, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,194	$ 3,035
Less accumulated depreciation and amortization	(785)	(130)
Property and equipment, net	2,409	2,905
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,430	2,417
Office and Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	290	214
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	$ 430	$ 360

Certain Balance Sheet Items - A

Certain Balance Sheet Items - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 0.8	$ 0.1

Certain Balance Sheet Items - O

Certain Balance Sheet Items - Other Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued compensation	$ 2,013	$ 2,759
Operating lease liability	407
Accrued professional fees and other	302	670
Deferred rent		425
Property and equipment, net	$ 2,722	$ 3,854

Collaboration and License Agr_2

Collaboration and License Agreements - Additional Information (Detail)	1 Months Ended			3 Months Ended	12 Months Ended
	Jun. 30, 2010Agreement	Jun. 30, 2006	Jun. 30, 1998USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jan. 01, 2018USD ($)
Contract Initiation [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligations							$ 5,000,000
Pharmacokinetics of Arhalofenate [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligations							$ 5,000,000
Kowa Pharmaceuticals America Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non-refundable upfront payment				$ 5,000,000
Kowa Pharmaceuticals America Inc [Member] | Pharmacokinetics of Arhalofenate [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments				195,000,000
Kowa Pharmaceuticals America Inc [Member] | Phase 3 Study [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments				$ 195,000,000
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

Term Loan - Additional Informat

Term Loan - Additional Information (Detail) - USD ($)	Jun. 04, 2018	Dec. 31, 2018	Aug. 07, 2015
Debt Instrument [Line Items]
Repayment of facility loan		$ 6,527,000
Loss on extinguishment of debt		$ (407,000)
2015 Term Loan Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 15,000,000
Repayment of facility loan	$ 4,200,000
Facility loan, final fee	700,000
Prepayment penalty	100,000
Loss on extinguishment of debt	$ 400,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Indemnification liabilities	$ 0	$ 0
Accrued in the consolidated balance sheets related to indemnification obligations	$ 0

Leases - Summary of Maturities

Leases - Summary of Maturities of Operating Lease Liabilities (Detail) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 647
2021	667
2022	686
2023	707
2024	30
Total undiscounted future minimum lease payments	2,737
Less: Imputed interest	587
Total operating lease liability	2,150
Less: Current portion of operating lease liability (included in other accrued liabilities)	407
Long-term portion of operating lease liability	$ 1,743

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)ft²Facility	Dec. 31, 2018USD ($)
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term	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%
Operating lease right-of-use asset	$ 235
Operating lease liability	2,150
Short term portion of operating lease liability	$ 407
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherAccruedLiabilitiesCurrent
Long-term portion of operating lease liability	$ 1,743
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OperatingLeaseLiabilityNoncurrent
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	$ 400

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2018	Feb. 01, 2018	Aug. 07, 2015	Feb. 28, 2019	Sep. 30, 2013	Dec. 31, 2019	Mar. 08, 2019	Dec. 31, 2018	Dec. 31, 2013	Mar. 11, 2019	Dec. 28, 2018
Class of Stock [Line Items]
Preferred stock, shares authorized						10,000,000		10,000,000
Common stock, shares authorized						100,000,000		100,000,000
Common stock, shares issued		13,340,000				68,882,459	8,000,000	59,456,493		1,200,000
Common stock offering price		$ 10.80					$ 12.50
Net proceeds from public offering		$ 135,500				$ 107,746	$ 107,700	$ 135,520
Registration filed on Form S-3		$ 200,000									$ 200,000
Terminated amount of shelf registration statement				$ 200,000
Change in fair value of warrant liability								$ 3,710
Warrants exercised								443,505
Cash proceeds from exercise of warrants								$ 2,550
Common stock warrants exercised in cashless transactions								938,300
Net shares issued through cashless warrant exercises								513,340
Number of unexercised warrants expired	79,150
Gain on extinguishment of warrant liability	$ 400							$ 422
Number of warrants outstanding						0
Warrants, Exercise price of $5.75 per share [Member]
Class of Stock [Line Items]
Issued warrants to purchase common stock									1,741,788
Exercise price of common stock									$ 5.75
Warrant term									5 years
Warrants, Exercise Price of $5.00 Per Share [Member]
Class of Stock [Line Items]
Issued warrants to purchase common stock					121,739
Exercise price of common stock					$ 5
Warrant term					7 years
Warrants, Exercise Price of $2.84 Per Share [Member]
Class of Stock [Line Items]
Issued warrants to purchase common stock			114,436
Exercise price of common stock			$ 2.84
Warrant term			10 years

Stockholder's Equity - Reserved

Stockholder's Equity - Reserved Shares of Authorized but Unissued Common Stock (Detail) - shares	Dec. 31, 2019	Dec. 31, 2018
Common Stock Warrants [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	9,143,863	6,991,570
Equity Incentive Plan [Member]
Class of Stock [Line Items]
Total reserved shares of common stock	9,143,863	6,991,570

Stock Plan and Stock-Based Co_3

Stock Plan and Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jan. 01, 2020	Sep. 30, 2013	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2013	Jun. 30, 2014	Apr. 30, 2014	Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised			$ 400	$ 4,900
Fair value of options vested			9,900	7,000
Unamortized employee and non-employee stock-based compensation expense			$ 15,000
Unamortized employee and non-employee stock-based compensation expense recognized period			2 years 4 months 24 days
Stock-based compensation expense			$ 9,558	$ 7,013
Stock options outstanding			6,726,695	5,593,132
Options to purchase common stock, unvested			0
Scientific Advisors and Consultants [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			48 months
Stock-based compensation expense			$ 100	$ 100
Issued warrants to purchase common stock				10,000
Options to purchase common stock, unvested			9,646
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			2,315,727
2013 Equity Incentive Plan [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in shares reserved for issuance	0
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						252,752	500,000	252,752	252,752
Exercisable weighted average price per share						$ 5.21		$ 5.21	$ 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	129,776
Incentive Awards [Member] | First Tranche [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incentive awards vested percentage						100.00%

Stock Plan and Stock-Based Co_4

Stock Plan and Stock-Based Compensation - Summary of Stock Option Grants, Including Performance Options (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)$ / sharesshares
Shares Subject to Outstanding Options
Outstanding at the beginning of period | shares	5,593,132
Options granted | shares	2,775,360
Options exercised | shares	(223,631)
Options forfeited | shares	(1,127,078)
Options expired | shares	(291,088)
Outstanding as end of period | shares	6,726,695
Vested and expected to vest | shares	6,726,695
Exercisable | shares	3,769,835
Weighted-Average Exercise Price of Options
Outstanding at the beginning of period | $ / shares	$ 7.68
Options granted | $ / shares	8.25
Options exercised | $ / shares	1.67
Options forfeited | $ / shares	8.63
Options expired | $ / shares	9.42
Outstanding as end of period | $ / shares	7.88
Vested and expected to vest | $ / shares	7.88
Exercisable | $ / shares	$ 6.87
Weighted-Average Remaining Contractual Term (Years)
Outstanding	7 years 4 months 20 days
Vested and expected to vest	7 years 4 months 20 days
Exercisable	6 years 5 months 19 days
Aggregate Intrinsic Value (In Thousands)
Outstanding | $	$ 369
Vested and expected to vest | $	369
Exercisable | $	$ 328

Stock Plan and Stock-Based Co_5

Stock Plan and Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 9,558	$ 7,013
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	4,361	2,760
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	5,197	4,253
Restructuring charges [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	910
Stock-Based Compensation Expense Including Restructuring charges [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 10,468	$ 7,013

Stock Plan and Stock-Based Co_6

Stock Plan and Stock-Based Compensation - Estimated Weighted-Average Grant Date Fair Value (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	6 years 2 months 12 days	6 years 2 months 12 days
Expected volatility	76.00%	77.00%
Risk-free interest rate	2.13%	2.62%
Expected dividend yield	0.00%
Weighted-average grant date fair value per share	$ 5.60	$ 8.14

401(k) Plan - Additional Inform

401(k) Plan - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Pension And Other Postretirement Plans Disclosure [Abstract]
Employees contribution to qualified savings plan	$ 750,000	$ 750,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	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 2039. The federal research and development and federal orphan drug tax credit carryforwards will expire beginning in 2020 through 2039, and the state tax credit will carry forward indefinitely.
Provision for income taxes	$ 0	$ 0
Net valuation allowance increase (decrease)	$ 23,600,000	29,500,000
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	$ 435,900,000
Net operating loss carryforward	435,900,000
Research and development tax credit carry forwards	18,100,000
Domestic Tax Authority [Member] | Orphan Drug [Member]
Income Tax [Line Items]
Research and development tax credit carry forwards	$ 9,800,000
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	$ 224,500,000
Net operating loss carryforward	224,500,000
Research and development tax credit carry forwards	$ 5,300,000
State and Local Jurisdiction [Member] | Federal [member]
Income Tax [Line Items]
Federal net operating loss		180,200,000	$ 255,700,000
Net operating loss carryforward		$ 180,200,000	$ 255,700,000
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			2039

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Federal and state net operating loss carryforwards	$ 107,213	$ 85,571
Federal and state research and development tax credit carryforwards	25,661	18,590
Capitalized research and development	4,725	10,466
Stock based compensation	3,562	2,848
Other	1,199	1,499
Total deferred tax assets	142,360	118,974
Deferred tax liabilities:
Depreciation and amortization	(372)	(622)
Other	(49)
Total deferred tax liabilities	(421)	(622)
Valuation allowance	(141,939)	(118,352)
Net deferred tax assets

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, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax benefit at federal statutory tax rate	$ (21,589)	$ (15,235)
Change in valuation allowance	23,587	29,501
State income taxes, net of federal benefit	3,810	(10,112)
Research credits	(6,555)	(4,717)
Other	747	$ 563
Income tax (benefit) expense

Income Taxes - Summary of Gross

Income Taxes - Summary of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Balance at beginning of period	$ 4,584	$ 3,295
Increases related to prior year tax positions	83	6
Increases related to tax positions	1,719	1,283
Balance at end of period	$ 6,386	$ 4,584

Restructuring (Details)

Restructuring (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Restructuring Cost and Reserve [Line Items]
Balances as of January 1, 2019
Restructuring charges	3,325
Reductions for cash payments	(132)
Balances as of December 31, 2019	3,193
Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Balances as of January 1, 2019
Restructuring charges	2,912
Reductions for cash payments	(132)
Balances as of December 31, 2019	2,780
Contract Termination Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balances as of January 1, 2019
Restructuring charges	413
Balances as of December 31, 2019	$ 413

Restructuring - Additional Info

Restructuring - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and Impairment charges	$ 5,100
Restructuring charges	5,075
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