Arcus Biosciences (RCUS) 10-Q 5 May 20 2020 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Trading Symbol	RCUS
Entity Registrant Name	Arcus Biosciences, Inc.
Entity Central Index Key	0001724521
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-38419
Entity Tax Identification Number	47-3898435
Entity Address, Address Line One	3928 Point Eden Way
Entity Address, City or Town	Hayward
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94545
City Area Code	510
Local Phone Number	694-6200
Entity Common Stock, Shares Outstanding		46,046,026
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, Par Value $0.0001 Per Share
Security Exchange Name	NYSE
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	[1]
Current assets:
Cash and cash equivalents	$ 67,326	$ 57,937
Short-term investments	90,540	130,333
Receivable from collaboration partners	344	132
Prepaid expenses and other current assets	8,007	4,303
Total current assets	166,217	192,705
Property and equipment, net	8,761	9,330
Restricted cash	203	203
Other long-term assets	963	872
Total assets	176,144	203,110
Current liabilities
Accounts payable	2,426	4,704
Accrued liabilities	10,170	9,522
Deferred revenue, current	7,000	7,000
Other current liabilities	1,408	1,480
Total current liabilities	21,004	22,706
Deferred revenue, noncurrent	10,272	12,022
Deferred rent	3,590	3,734
Other long-term liabilities	640	806
Total liabilities	35,506	39,268
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of March 31, 2020 and December 31, 2019; no shares issued and outstanding as of March 31, 2020 and December 31, 2019	0	0
Common stock, $0.0001 par value, 400,000,000 shares authorized as of March 31, 2020 and December 31, 2019; 45,982,788 and 45,925,004 shares issued and outstanding as of March 31, 2020 and December 31, 2019, respectively	4	4
Additional paid-in capital	373,425	369,100
Accumulated deficit	(233,079)	(205,326)
Accumulated other comprehensive income	288	64
Total stockholders’ equity	140,638	163,842	[2]
Total liabilities, convertible preferred stock and stockholders’ equity	$ 176,144	$ 203,110
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2019 has been derived from the audited financial statements as of that date.
[2]	The balances as of December 31, 2019 and 2018 have been derived from the audited financial statements as of that date.

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	45,982,788	45,925,004
Common stock, shares outstanding	45,982,788	45,925,004

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Collaboration and license revenue	$ 1,750	$ 1,750
Type of Revenue [Extensible List]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Operating expenses:
Research and development	$ 23,142	$ 15,554
General and administrative	7,008	4,969
Total operating expenses	30,150	20,523
Loss from operations	(28,400)	(18,773)
Non-operating income (expense):
Interest and other income, net	647	1,534
Gain on deemed sale from equity method investee	482	0
Share of loss from equity method investee	(482)	(431)
Total non-operating income, net	647	1,103
Net loss	(27,753)	(17,670)
Other comprehensive income	224	136
Comprehensive loss	$ (27,529)	$ (17,534)
Net loss per share, basic and diluted	$ (0.63)	$ (0.41)
Weighted-average number of shares used to compute basic and diluted net loss per share	44,282,607	43,508,592

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total		Common Stock		Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Balance at Dec. 31, 2018	[1]	$ 234,942		$ 4		$ 357,873	$ (122,828)	$ (107)
Balance, shares at Dec. 31, 2018	[1]			43,610,823
Cumulative effect adjustment upon adoption of ASC 606 | ASC 606		2,212					2,212
Issuance of common stock upon exercise of stock options, shares				69
Vesting of early exercised stock options and restricted stock		273				273
Vesting of early exercised stock options and restricted stock, shares				114,934
Stock-based compensation		1,674				1,674
Other comprehensive loss		136						136
Net loss		(17,670)					(17,670)
Balance at Mar. 31, 2019		221,567		$ 4		359,820	(138,286)	29
Balance, shares at Mar. 31, 2019				43,725,826
Balance at Dec. 31, 2019	[1]	$ 163,842	[2]	$ 4		369,100	(205,326)	64
Balance, shares at Dec. 31, 2019		45,925,004		44,212,195	[1]
Issuance of common stock upon exercise of stock options		$ 643				643
Issuance of common stock upon exercise of stock options, shares				59,939
Vesting of early exercised stock options and restricted stock		220				220
Vesting of early exercised stock options and restricted stock, shares				77,388
Stock-based compensation		3,462				3,462
Other comprehensive loss		224						224
Net loss		(27,753)					(27,753)
Balance at Mar. 31, 2020		$ 140,638		$ 4		$ 373,425	$ (233,079)	$ 288
Balance, shares at Mar. 31, 2020		45,982,788		44,349,522
[1]	The balances as of December 31, 2019 and 2018 have been derived from the audited financial statements as of that date.
[2]	The Condensed Consolidated Balance Sheet as of December 31, 2019 has been derived from the audited financial statements as of that date.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flow from operating activities
Net loss	$ (27,753)	$ (17,670)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	3,462	1,674
Depreciation and amortization	842	953
Share of loss from equity method investee	482	431
Gain on deemed sale from equity method investee	(482)	0
Amortization of premiums on investments	(248)	(747)
Changes in operating assets and liabilities:
Receivable from collaboration partners	(212)	0
Amounts owed by a related party	0	83
Prepaid expenses and other current assets	(3,704)	(759)
Other long-term assets	(91)	(30)
Accounts payable	(2,342)	(517)
Accrued liabilities	648	1,606
Other current liabilities	0	14
Deferred revenue	(1,750)	(1,750)
Deferred rent	(129)	(127)
Net cash used in operating activities	(31,277)	(16,839)
Cash flow from investing activities
Purchases of short-term and long-term investments	(8,885)	(72,407)
Proceeds from maturities of short-term and long-term investments	49,150	87,314
Purchases of property and equipment	(209)	(628)
Net cash provided by investing activities	40,056	14,279
Cash flow from financing activities
Proceeds from issuance of common stock	643	0
Repurchase of unvested shares of stock	(33)	(5)
Net cash provided by (used in) financing activities	610	(5)
Net increase (decrease) in cash and cash equivalents	9,389	(2,565)
Cash, cash equivalents and restricted cash at beginning of period	58,140	71,267
Cash, cash equivalents and restricted cash at end of period	67,529	68,702
Non-cash investing and financing activities:
Unpaid portion of property and equipment purchases included in accounts payable and accrued liabilities	76	380
Vesting of early exercised stock options and restricted stock	$ 220	$ 273

Organization

Organization	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	Note 1. Description of Business Arcus Biosciences, Inc. (the Company) is a clinical-stage biopharmaceutical company focused on creating best-in-class cancer therapies. The Company’s initial focus has been on well-characterized biological pathways with significant scientific data supporting their importance. Since its inception in 2015, the Company has built a robust and highly efficient drug discovery capability to create highly differentiated small molecules, which the Company is developing in combination with its in-licensed monoclonal antibodies through rationally designed, indication-specific, adaptive clinical trial designs. Liquidity and Capital Resources As of March 31, 2020, the Company had cash and investments of $157.9 million, which are cash, cash equivalents, and investments in marketable securities, which the Company believes will be sufficient to fund its planned operations for a period of at least twelve months following the filing date of this report.

Significant Accounting Policies

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	Note 2. Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (SEC). Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the Company’s opinion, all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation of the results of operations and cash flows for the periods presented have been included. Operating results for the three months ended March 31, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020 or for any future period. The balance sheet as of December 31, 2019 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2019 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 5, 2020. From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB), or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s condensed consolidated financial statements upon adoption. Under the Jumpstart Our Business Startups Act of 2012, as amended (the JOBS Act), the Company meets the definition of an emerging growth company and has elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. The Company will remain an emerging growth company until the earliest of (1) the last day of its first fiscal year (a) following the fifth anniversary of the completion of its initial public offering, (b) in which the Company has a total annual gross revenue of at least $1.07 billion, or (c) in which the Company is deemed to be a large accelerated filer, which means the market value of the common stock that is held by non-affiliates exceeds $700.0 million of the prior June 30th or (2) the date on which the Company has issued more than $1.0 billion in non-convertible debt securities during the prior three-year period. Principles of Consolidation The Company established a wholly-owned subsidiary in Australia in 2017 and a wholly-owned subsidiary in Ireland in 2019. The condensed consolidated financial statements include the Company’s accounts and those of its wholly-owned subsidiaries. All intercompany accounts, transactions and balances have been eliminated. Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, as well as related disclosures of contingent assets and liabilities. Estimates were used to determine the value of stock-based awards and other issuances, accruals for research and development costs, useful lives of long-lived assets, and uncertain tax positions. Actual results could differ materially from the Company’s estimates. Cash Equivalents and Short-Term Investments Cash equivalents include marketable securities having an original maturity of three months or less at the time of purchase. Short-term investments have maturities of greater than three months and up to twelve months at the time of purchase. Collectively, cash equivalents, short-term and long-term investments are considered available-for-sale and are recorded at fair value. Unrealized gains and losses are recorded in accumulated other comprehensive loss. Realized gains and losses are included in interest and other income, net in the condensed consolidated statements of operations and comprehensive income or loss. The basis on which the cost of a security that is sold or an amount that is reclassified out of accumulated other comprehensive income or loss into earnings is determined using the specific identification method. Reconciliation of Cash, Cash Equivalents, and Restricted Cash as Reported in Condensed Consolidated Statements of Cash Flows Restricted cash at March 31, 2020 and December 31, 2019 represents cash balances held as security in connection with the Company’s facility lease agreements. The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the condensed consolidated balance sheets to the total shown in the condensed consolidated statements of cash flows (in thousands): March 31, 2020 December 31, 2019 Cash and cash equivalents $ 67,326 $ 57,937 Restricted cash 203 203 Cash, cash equivalents and restricted cash $ 67,529 $ 58,140 Concentration of Credit Risk Cash equivalents, short-term and long-term investments are financial instruments that potentially subject the Company to concentrations of credit risk. The Company invests in money market funds, treasury bills and notes, government bonds, commercial paper and corporate notes. The Company limits its credit risk associated with cash equivalents, short-term and long-term investments by placing them with banks and institutions it believes are credit worthy and in highly rated investments. Research and Development Expenses Research and development costs are expensed as incurred. Research and development expenses consist primarily of personnel costs for the Company’s research and development employees, costs incurred to third-party service providers for the conduct of research, preclinical and clinical studies, laboratory supplies and equipment maintenance costs, product license fees, consulting and other related expenses. The Company estimates research, preclinical and clinical study expenses based on services performed, pursuant to contracts with third-party research and development organizations that conduct and manage research, preclinical and clinical activities on its behalf. The Company estimates these expenses based on discussions with internal management personnel and external service providers as to the progress or stage of completion of services and the contracted fees to be paid for such services. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments associated with licensing agreements to acquire licenses to develop, use, manufacture and commercialize products that have not reached technological feasibility and do not have alternative future use are expensed as incurred. Payments made to third parties under these arrangements in advance of the performance of the related services by the third parties are recorded as prepaid expenses until the services are rendered. Recently Adopted Accounting Standards In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. ASU 2019-12 reduces costs and complexity of applying accounting standards while maintaining the usefulness of the information provided to users of financial statements. While not required to be adopted until 2021 for most calendar year public business entities, early adoption is permitted for any financial statements not yet issued. The Company has decided to early adopt this ASU as of January 1, 2020, with an immaterial impact on the financial statements. Recently Issued Accounting Standards or Updates Not Yet Effective In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases In June 2016, the FASB issued ASU No. 2016 Measurement of Credit Losses on Financial Instruments As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASU 2016-13 is effective for the Company for the year ended December 31, 2023, and all interim periods within that fiscal year. Early adoption is permitted. The adoption of this standard is not expected to have a material impact on the Company’s condensed consolidated financial statements. In August 2018, the FASB issued ASU No.2018-13 (Topic 820), Fair Value Measurement. In August 2018, the FASB issued ASU No.2018-15 (Subtopic 350-40), Intangible – Goodwill and Other – Internal-Use Software. In November 2018, the FASB issued ASU No. 2018-18 (Topic 808), Collaborative Arrangements

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 3. Fair Value Measurements Financial assets and liabilities are recorded at fair value. The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value and expands disclosures regarding fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2—Inputs (other than quoted market prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life. Level 3—Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. During the periods presented, the Company has not changed the manner in which it values assets and liabilities that are measured at fair value. The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers within the hierarchy as of March 31, 2020 and December 31, 2019. The following tables set forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): March 31, 2020 Total Level 1 Level 2 Level 3 Money market funds $ 67,326 $ 67,326 $ - $ - U.S. government treasury and agency securities 55,969 - 55,969 - Corporate securities and commercial paper 34,571 - 34,571 - Total assets measured at fair value $ 157,866 $ 67,326 $ 90,540 $ - December 31, 2019 Total Level 1 Level 2 Level 3 Money market funds $ 45,498 $ 45,498 $ - $ - U.S. government treasury and agency securities 74,854 - 74,854 - Corporate securities and commercial paper 67,918 - 67,918 - Total assets measured at fair value $ 188,270 $ 45,498 $ 142,772 $ - Classified as (with contractual maturities): March 31, 2020 December 31, 2019 Cash and cash equivalents $ 67,326 $ 57,937 Short-term investments (due within one year) 90,540 130,333 Total cash, cash equivalents and investments in marketable securities $ 157,866 $ 188,270 Investments in marketable securities are classified as available-for-sale. At March 31, 2020 and December 31, 2019, the balance in the Company’s accumulated other comprehensive loss comprised activity related to the Company’s available-for-sale marketable securities. There were no realized gains or losses recognized on the sale or maturity of available-for-sale marketable securities as of March 31, 2020 and December 31, 2019, and as a result, the Company did not reclassify any amounts out of accumulated other comprehensive loss for the periods then ended. The Company has a limited number of available-for-sale marketable securities in loss positions as of March 31, 2020, which the Company does not intend to sell and has concluded it will not be required to sell before recovery of the amortized cost for the investment at maturity. The fair value and amortized cost of investments in marketable securities by major security type as of March 31, 2020 and December 31, 2019 are presented in the tables that follow (in thousands): Amortized Cost Unrealized Gain Unrealized Loss Fair Value As of March 31, 2020: Money market funds $ 67,326 $ - $ - $ 67,326 U.S. government treasury and agency securities 55,663 306 - 55,969 Corporate securities and commercial paper 34,589 9 (27 ) 34,571 Total $ 157,578 $ 315 $ (27 ) $ 157,866 Amortized Cost Unrealized Gain Unrealized Loss Fair Value As of December 31, 2019: Money market funds $ 45,498 $ - $ - $ 45,498 U.S. government treasury and agency securities 74,854 12 (1 ) 74,865 Corporate securities and commercial paper 67,918 55 (2 ) 67,971 Total $ 188,270 $ 67 $ (3 ) $ 188,334

Equity Investment

Equity Investment	3 Months Ended
	Mar. 31, 2020
Inventory Disclosure [Abstract]
Equity Investment	Note 4: Equity Investment In 2016, the Company purchased approximately 3.6 million shares of common stock of PACT Pharma, Inc. (PACT Pharma), a privately funded, early-stage biopharmaceutical company focused on adoptive cell therapy, and 1.0 million shares of Series A preferred stock. The Company determined the fair value of such investment to be insignificant to the Company’s 2016 financial statements given the start-up nature of operations of PACT Pharma, and it was recorded at a nominal amount. The Company also received certain warrants to purchase PACT Pharma common stock exercisable upon PACT Pharma’s achievement of certain valuation thresholds pursuant to a Master Services Agreement between the Company and PACT Pharma (the PACT Agreement), which agreement has since expired. The Company determined PACT Pharma to be a variable interest entity, and that the Company has a variable interest in PACT. However, because the Company is not the primary beneficiary of PACT Pharma, it is not required to consolidate the results of operations of PACT Pharma within its condensed consolidated financial statements. The Company’s investment in PACT Pharma is accounted for as an equity method investment, and as a result the Company records its share of PACT Pharma’s operating results in interest and other income, net, in its condensed consolidated statements of operations and comprehensive loss. The investment balance was zero at March 31, 2020 and December 31, 2019. In January 2020, PACT Pharma closed its Series C convertible preferred stock financing. The Company did not participate in this financing and therefore its equity ownership percentage in PACT Pharma decreased. As a result of the dilution in its equity ownership percentage and an increase in PACT Pharma’s estimated fair value per share, the Company realized a $1.3 million gain on deemed sale from equity method investee during the quarter ended March 31, 2020. After applying the $0.8 million in losses accumulated in prior periods when the equity investment balance was zero, the Company recorded a gain of $0.5 million and an increase to the fair value of the investment balance in the consolidated balance sheet as of March 31, 2020 by the same amount. The Company’s share of PACT Pharma’s losses for the three months ended March 31, 2020 exceeded the gains on deemed sale recognized as a result of the Series C financing. Since the Company has no obligation to provide cash financing to PACT Pharma, no additional losses are being recorded beyond the investment’s carrying amount. For the three months ended March 31, 2020, the Company recorded $0.5 million for its share of PACT Pharma’s operating losses. No losses were recognized during the three months ended March 31, 2019 because the value of the investment at that date was zero. The unrecognized equity method losses in excess of the Company’s investment was $0.1 million as of March 31, 2020. At March 31, 2020 and December 31, 2019, the Company determined the fair value of the warrants to be insignificant to the condensed consolidated financial statements.

License and Collaboration Agree

License and Collaboration Agreements	3 Months Ended
	Mar. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
License and Collaboration Agreements	Note 5. License and Collaboration Agreements Taiho Pharmaceutical Co., Ltd In September 2017, the Company and Taiho entered into an option and license agreement (the Taiho Agreement) to collaborate on the potential development and commercialization of certain investigational products from the Company’s portfolio in Japan and certain other territories in Asia (excluding China) (the Taiho Territory). The Taiho Agreement provides Taiho with exclusive options, over a five-year period (the Option Period), to obtain an exclusive development and commercialization license to clinical stage investigational products from the Company’s programs (each, an Arcus Program). In consideration for the exclusive options and other rights contained in the Taiho Agreement, Taiho agreed to make non-refundable, non-creditable cash payments to the Company totaling $35.0 million, of which the Company received $25.0 million during 2017. An additional $5.0 million was received in 2018 and the remaining $5.0 million was received in 2019. In the event that the Company has not initiated IND enabling studies for at least five Arcus Programs prior to the expiration of the Option Period, Taiho may elect to extend the Option Period, up to a maximum of seven years, subject to an extension fee. For each option that Taiho elects to exercise, Taiho will be obligated to make an option exercise payment of between $3.0 million to $15.0 million, depending on the development stage of the applicable Arcus Program for which the option is exercised. In addition, the Taiho Agreement provides that the Company is eligible to receive additional clinical and regulatory milestones totaling up to $130.0 million per Arcus Program, and it will be eligible to receive contingent payments of up to $145.0 million per Arcus Program associated with the achievement of specified levels of Taiho net sales in the Taiho Territory. In addition, the Company will receive royalties ranging from high single-digits to mid-teens on net sales of licensed products in the Taiho Territory. Royalties will be payable on a licensed product-by-licensed product and country-by-country basis during the period of time commencing on the first commercial sale of a licensed product in a country and ending upon the later of: (a) ten (10) years from the date of first commercial sale of such licensed product in such country; and (b) expiration of the last-to-expire valid claim of the Company’s patents covering the manufacture, use or sale or exploitation of such licensed product in such country (the Royalty Term). The Company evaluated the Taiho Agreement under ASC 606 and determined that the current performance obligations consist of (1) the research and development services, in which the Company will use commercially reasonable efforts to initiate IND enabling studies for at least five Arcus Programs, as well as further develop such Arcus Programs during the term of the Agreement, and (2) the obligation to participate on the joint steering committee. These deliverables are non-contingent in nature. The Company determined that the obligation to participate in the joint steering committee does not have stand-alone value to Taiho because the committee’s primary purpose is to monitor and govern the research and development activities and, hence, it is inseparable from the research and development services. The Company’s assessment of the transaction price included an analysis of amounts it expected to receive, which at contract inception consisted of the upfront cash payment of $20.0 million due upon contract execution in September 2017, a $5.0 million payment due within 30 days of contract execution, an anniversary payment of $5.0 million due in 2018, and a final anniversary payment of $5.0 million due in 2019. All payments were made by Taiho as they became due and payable so given this successful collection history, the Company considers the entire $35.0 million in non-refundable fees to be the initial transaction price. The Company determined that the combined performance obligation of the research and development services and the obligation to participate on the joint steering committee are satisfied over time. The Company uses a time-elapsed input method to measure progress toward satisfying its performance obligation, which is the method the Company believes most faithfully depicts the Company’s performance in transferring the promised services during the time period in which Taiho has access to the Company’s research and development activities. Accordingly, the transaction price of $35.0 million is being recognized using this input method over the estimated performance period of five years. The Company also concluded that, at the inception of the agreement, Taiho’s exclusive options are not considered material rights as the options do not contain a significant and incremental discount. The Company therefore excludes the exclusive options from the initial transaction price and accounts for them as separate contracts. In 2018, Taiho exercised its option to the Company’s adenosine receptor antagonist program, including AB928, for a fee of $3.0 million, which was recognized by the Company as revenue during the year ended December 31, 2018 under Topic 605. The adoption of Topic 606 in 2019 had no effect on the revenue recognized for this fee. In 2019, Taiho exercised its option to the Company’s anti-PD-1 antibody program, including zimberelimab (formerly referred to as AB122) for a fee of $8.0 million. The Company identified one performance obligation, the delivery of the license, which was completed in 2019. The transaction price was determined to be the payment of $8.0 million, which was recognized by the Company as licensing revenue during the year ended December 31, 2019 under Topic 606. Upon the option exercises, Taiho gained sole responsibility for the development and commercialization of the licensed products from within the programs in the Taiho Territory. The Company also determined that the clinical and regulatory milestone payments under the Taiho Agreement are variable consideration under Topic 606 which need to be added to the transaction price when it is probable that a significant revenue reversal will not occur. Based on the nature of the clinical and regulatory milestones, such as the regulatory approvals which are not within the Company’s control, the Company will not consider achievement of such milestones to be probable until the uncertainty associated with the milestones has been resolved. When it is probable that a significant reversal of revenue will not occur, the milestone payment will be added to the transaction price, which will then be allocated to each performance obligation, on a relative standalone selling price basis, for which the Company recognizes revenue. The Company also considers the contingent payments due from Taiho upon the achievement of specified sales volumes to be similar to royalty payments. The Company considers the license to be the predominant item to which the royalties relate. The Company will recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). As of March 31, 2020, no sales milestone or royalty revenue has been recognized. The Taiho Agreement shall remain in effect until expiry of all Royalty Terms for the licensed products, in each case subject to certain exceptions. During each of the three months ended March 31, 2020 and 2019, the Company recognized a total of $1.8 million of revenue under the Taiho Agreement, consisting of revenue recognized for the non-refundable upfront research and development fees. As of March 31, 2020, the Company recorded deferred revenue, current and deferred revenue, noncurrent of $7.0 million and $10.3 million, respectively, in its condensed consolidated balance sheet. Changes in Deferred Revenue Balances The Company recognized the following revenue as a result of changes in the deferred revenue balance during the period below (in thousands): Three Months Ended March 31, Revenue recognized in the period from: 2020 2019 Amounts included in deferred revenue at the beginning of the period $ 1,750 $ 1,750 Performance obligations satisfied in previous period - - WuXi Biologics License Agreement The Company entered into a license agreement (the WuXi Agreement) with WuXi Biologics (Cayman) Inc. (WuXi Biologics) in August 2017, as subsequently amended in June 2019, in which it obtained an exclusive license to develop, use, manufacture, and commercialize products including an anti-PD-1 antibody worldwide except for Greater China and Thailand. From the inception of the WuXi Agreement through March 31, 2020, the Company has made upfront and milestone payments of $26.0 million and incurred a sub-license fee of $1.2 million. The sub-license fee was incurred in the fourth quarter of 2019 and paid in the first quarter of 2020. These payments were recorded as research and development expense, as the products had not reached technological feasibility and do not have an alternative future use. The WuXi Agreement also provides for clinical and regulatory milestone payments, commercialization milestone payments of up to $375.0 million, and tiered royalty payments to be made to WuXi Biologics that range from the high single-digits to low teens of net sales by the Company of licensed products. The Company incurred no expense on the WuXi Agreement during the three months ended March 31, 2020. Abmuno License Agreement In December 2016, the Company entered into a license agreement (the Abmuno Agreement) with Abmuno Therapeutics LLC (Abmuno) for a worldwide exclusive license to develop, use, manufacture, and commercialize products that include an anti-TIGIT antibody, including AB154. Under the Abmuno Agreement, the Company has made upfront and milestone payments totaling $6.6 million as of December 31, 2019. No upfront or milestone payments were made under the Abmuno Agreement during the three months ended March 31, 2020 or 2019, respectively. Genentech Collaboration Agreement In December 2019, the Company and Genentech, through F. Hoffmann-La Roche Ltd (collectively, Genentech) entered into a Master Clinical Collaboration Agreement (the Genentech Agreement) pursuant to which the parties may conduct combination clinical studies involving Genentech’s monoclonal antibody, atezolizumab (TECENTRIQ®) and the Company’s investigational products. Pursuant to the Genentech Agreement, the parties entered into Trial Supplements for the evaluation of AB928 and atezolizumab utilizing the MORPHEUS platform in two separate study indications: second and third line metastatic colorectal cancer; and first line metastatic pancreatic cancer. The Company and Genentech will each supply their respective investigational products for use in the collaboration studies and will share a portion of the development costs under specific terms as set forth in the agreement. No expense was incurred on this collaboration for the quarter ended March 31, 2020. Strata Collaboration Agreement On April 30, 2019, the Company and Strata Oncology, Inc. (Strata) entered into a Co-Development and Collaboration Agreement (the Co-Development and Collaboration Agreement) to pursue a clinical development collaboration utilizing Strata’s precision drug development platform and proprietary biomarkers to evaluate zimberelimab, the Company’s clinical-stage anti-PD-1 antibody, in patients in a tumor-agnostic fashion. Under the terms of the Co-Development and Collaboration Agreement, the parties will share a portion of development costs for the clinical collaboration under specified terms. Strata is eligible to receive $2.5 million upon the achievement of a development milestone, as well as regulatory and commercial milestones of up to $125.0 million and up to double-digit royalties on U.S. net sales of zimberelimab in the biomarker-identified indication. From the inception of the Agreement through March 31, 2020, the Company has made a milestone payment of $2.5 million and has incurred expenses of $1.4 million, of which $0.3 million had been reimbursed by Strata as development cost sharing. These payments were recorded as research and development expense. As further consideration in connection with the Co-Development and Collaboration Agreement, the Company issued to Strata 1,257,651 restricted shares of its common stock with an initial measured fair value of $15.0 million, which are subject to vesting based upon the achievement of specified regulatory milestones within certain timelines. Expense relating to the restricted shares subject to these milestones is recognized if it is considered probable that the associated shares will vest. The probability of achievement is assessed at the end of each quarterly period. As of March 31, 2020, the Company determined that none of the restricted shares were probable of vesting and, as a result, no compensation expense related to the restricted shares has been recognized to date. For the three months ended March 31, 2020, the Company incurred expenses of $0.4 million, of which $0.1 million had been reimbursed by Strata as development cost sharing. Net expenses related to this co-development agreement were recorded within research and development expenses.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	Note 6: Stock-Based Compensation In March 2018, the Company adopted the 2018 Equity Incentive Plan (2018 Plan). The 2018 Plan replaced the Company’s 2015 Stock Plan (2015 Plan) and 3,570,000 shares were reserved under the 2018 Plan, along with any shares remaining available for issuance under the Company’s 2015 Plan or outstanding awards under its 2015 Plan that subsequently expire, lapse unexercised or are forfeited to or repurchased by the Company. In January 2020, the Company adopted the 2020 Inducement Plan (2020 Plan). Under the 2020 Plan, 3,000,000 shares were reserved for issuance. Total stock-based compensation expense was recognized in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three months ended March 31, 2020 2019 Research and development $ 1,736 $ 847 General and administrative 1,726 827 Total stock-based compensation $ 3,462 $ 1,674

Accrued Liabilities

Accrued Liabilities	3 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Accrued Liabilities	Note 7. Accrued Liabilities Accrued liabilities consisted of the following (in thousands): As of March 31, 2020 As of December 31, 2019 Accrued personnel expenses $ 2,566 $ 4,571 Accrued research and development expenses 6,798 4,572 Professional fees 323 183 Other 483 196 Total $ 10,170 $ 9,522

Net Loss per Share

Net Loss per Share	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
Net Loss per Share	Note 8. 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 data): Three Months Ended March 31, 2020 2019 Numerator: Net loss $ (27,753 ) $ (17,670 ) Denominator: Weighted-average common shares outstanding 45,953,213 44,532,073 Less: weighted-average common shares subject to vesting (1,670,606 ) (1,023,481 ) Weighted-average common shares used to compute basic and diluted net loss per share 44,282,607 43,508,592 Net loss per share: basic and diluted $ (0.63 ) $ (0.41 ) The following outstanding potentially dilutive securities were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive: As of March 31, 2020 2019 Common stock options issued and outstanding 6,725,835 3,222,103 Unvested restricted common stock issued as part of collaboration agreement 1,257,651 - Unvested early exercised common stock options 375,615 811,300 Unvested restricted common stock - 115,741 Total 8,359,101 4,149,144

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (U.S. GAAP) for interim financial information and pursuant to Form 10-Q and Article 10 of Regulation S-X of the Securities and Exchange Commission (SEC). Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the Company’s opinion, all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation of the results of operations and cash flows for the periods presented have been included. Operating results for the three months ended March 31, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020 or for any future period. The balance sheet as of December 31, 2019 has been derived from audited consolidated financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2019 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 5, 2020. From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB), or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the impact of recently issued standards that are not yet effective will not have a material impact on the Company’s condensed consolidated financial statements upon adoption. Under the Jumpstart Our Business Startups Act of 2012, as amended (the JOBS Act), the Company meets the definition of an emerging growth company and has elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act. The Company will remain an emerging growth company until the earliest of (1) the last day of its first fiscal year (a) following the fifth anniversary of the completion of its initial public offering, (b) in which the Company has a total annual gross revenue of at least $1.07 billion, or (c) in which the Company is deemed to be a large accelerated filer, which means the market value of the common stock that is held by non-affiliates exceeds $700.0 million of the prior June 30th or (2) the date on which the Company has issued more than $1.0 billion in non-convertible debt securities during the prior three-year period.
Principles of Consolidation	Principles of Consolidation The Company established a wholly-owned subsidiary in Australia in 2017 and a wholly-owned subsidiary in Ireland in 2019. The condensed consolidated financial statements include the Company’s accounts and those of its wholly-owned subsidiaries. All intercompany accounts, transactions and balances have been eliminated.
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, as well as related disclosures of contingent assets and liabilities. Estimates were used to determine the value of stock-based awards and other issuances, accruals for research and development costs, useful lives of long-lived assets, and uncertain tax positions. Actual results could differ materially from the Company’s estimates.
Cash Equivalents and Short-Term Investments	Cash Equivalents and Short-Term Investments Cash equivalents include marketable securities having an original maturity of three months or less at the time of purchase. Short-term investments have maturities of greater than three months and up to twelve months at the time of purchase. Collectively, cash equivalents, short-term and long-term investments are considered available-for-sale and are recorded at fair value. Unrealized gains and losses are recorded in accumulated other comprehensive loss. Realized gains and losses are included in interest and other income, net in the condensed consolidated statements of operations and comprehensive income or loss. The basis on which the cost of a security that is sold or an amount that is reclassified out of accumulated other comprehensive income or loss into earnings is determined using the specific identification method.
Reconciliation of Cash, Cash Equivalents, and Restricted Cash as Reported in Condensed Consolidated Statements of Cash Flows	Reconciliation of Cash, Cash Equivalents, and Restricted Cash as Reported in Condensed Consolidated Statements of Cash Flows Restricted cash at March 31, 2020 and December 31, 2019 represents cash balances held as security in connection with the Company’s facility lease agreements. The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the condensed consolidated balance sheets to the total shown in the condensed consolidated statements of cash flows (in thousands): March 31, 2020 December 31, 2019 Cash and cash equivalents $ 67,326 $ 57,937 Restricted cash 203 203 Cash, cash equivalents and restricted cash $ 67,529 $ 58,140
Concentration of Credit Risk	Concentration of Credit Risk Cash equivalents, short-term and long-term investments are financial instruments that potentially subject the Company to concentrations of credit risk. The Company invests in money market funds, treasury bills and notes, government bonds, commercial paper and corporate notes. The Company limits its credit risk associated with cash equivalents, short-term and long-term investments by placing them with banks and institutions it believes are credit worthy and in highly rated investments.
Research and Development Expenses	Research and Development Expenses Research and development costs are expensed as incurred. Research and development expenses consist primarily of personnel costs for the Company’s research and development employees, costs incurred to third-party service providers for the conduct of research, preclinical and clinical studies, laboratory supplies and equipment maintenance costs, product license fees, consulting and other related expenses. The Company estimates research, preclinical and clinical study expenses based on services performed, pursuant to contracts with third-party research and development organizations that conduct and manage research, preclinical and clinical activities on its behalf. The Company estimates these expenses based on discussions with internal management personnel and external service providers as to the progress or stage of completion of services and the contracted fees to be paid for such services. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments associated with licensing agreements to acquire licenses to develop, use, manufacture and commercialize products that have not reached technological feasibility and do not have alternative future use are expensed as incurred. Payments made to third parties under these arrangements in advance of the performance of the related services by the third parties are recorded as prepaid expenses until the services are rendered.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. ASU 2019-12 reduces costs and complexity of applying accounting standards while maintaining the usefulness of the information provided to users of financial statements. While not required to be adopted until 2021 for most calendar year public business entities, early adoption is permitted for any financial statements not yet issued. The Company has decided to early adopt this ASU as of January 1, 2020, with an immaterial impact on the financial statements.
Recently Issued Accounting Standards or Updates Not Yet Effective	Recently Issued Accounting Standards or Updates Not Yet Effective In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases In June 2016, the FASB issued ASU No. 2016 Measurement of Credit Losses on Financial Instruments As a result of the Company having elected the extended transition period for complying with new or revised accounting standards pursuant to Section 107(b) of the JOBS Act, ASU 2016-13 is effective for the Company for the year ended December 31, 2023, and all interim periods within that fiscal year. Early adoption is permitted. The adoption of this standard is not expected to have a material impact on the Company’s condensed consolidated financial statements. In August 2018, the FASB issued ASU No.2018-13 (Topic 820), Fair Value Measurement. In August 2018, the FASB issued ASU No.2018-15 (Subtopic 350-40), Intangible – Goodwill and Other – Internal-Use Software. In November 2018, the FASB issued ASU No. 2018-18 (Topic 808), Collaborative Arrangements

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the condensed consolidated balance sheets to the total shown in the condensed consolidated statements of cash flows (in thousands): March 31, 2020 December 31, 2019 Cash and cash equivalents $ 67,326 $ 57,937 Restricted cash 203 203 Cash, cash equivalents and restricted cash $ 67,529 $ 58,140

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Financial Instruments Measured at Fair Value on Recurring Basis	The following tables set forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): March 31, 2020 Total Level 1 Level 2 Level 3 Money market funds $ 67,326 $ 67,326 $ - $ - U.S. government treasury and agency securities 55,969 - 55,969 - Corporate securities and commercial paper 34,571 - 34,571 - Total assets measured at fair value $ 157,866 $ 67,326 $ 90,540 $ - December 31, 2019 Total Level 1 Level 2 Level 3 Money market funds $ 45,498 $ 45,498 $ - $ - U.S. government treasury and agency securities 74,854 - 74,854 - Corporate securities and commercial paper 67,918 - 67,918 - Total assets measured at fair value $ 188,270 $ 45,498 $ 142,772 $ -
Schedule of Investments Classified as Available for Sale Securities with Contractual Maturities	Classified as (with contractual maturities): March 31, 2020 December 31, 2019 Cash and cash equivalents $ 67,326 $ 57,937 Short-term investments (due within one year) 90,540 130,333 Total cash, cash equivalents and investments in marketable securities $ 157,866 $ 188,270
Schedule of Fair Value and Amortized Cost of Investments in Marketable Securities by Major Security Type	. The fair value and amortized cost of investments in marketable securities by major security type as of March 31, 2020 and December 31, 2019 are presented in the tables that follow (in thousands): Amortized Cost Unrealized Gain Unrealized Loss Fair Value As of March 31, 2020: Money market funds $ 67,326 $ - $ - $ 67,326 U.S. government treasury and agency securities 55,663 306 - 55,969 Corporate securities and commercial paper 34,589 9 (27 ) 34,571 Total $ 157,578 $ 315 $ (27 ) $ 157,866 Amortized Cost Unrealized Gain Unrealized Loss Fair Value As of December 31, 2019: Money market funds $ 45,498 $ - $ - $ 45,498 U.S. government treasury and agency securities 74,854 12 (1 ) 74,865 Corporate securities and commercial paper 67,918 55 (2 ) 67,971 Total $ 188,270 $ 67 $ (3 ) $ 188,334

License and Collaboration Agr_2

License and Collaboration Agreements (Tables)	3 Months Ended
	Mar. 31, 2020
License And Collaboration Agreements [Abstract]
Summary of Revenue Recognized as a Result of Changes in Deferred Revenue	The Company recognized the following revenue as a result of changes in the deferred revenue balance during the period below (in thousands): Three Months Ended March 31, Revenue recognized in the period from: 2020 2019 Amounts included in deferred revenue at the beginning of the period $ 1,750 $ 1,750 Performance obligations satisfied in previous period - -

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock-Based Compensation Expense	Total stock-based compensation expense was recognized in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three months ended March 31, 2020 2019 Research and development $ 1,736 $ 847 General and administrative 1,726 827 Total stock-based compensation $ 3,462 $ 1,674

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Summary of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): As of March 31, 2020 As of December 31, 2019 Accrued personnel expenses $ 2,566 $ 4,571 Accrued research and development expenses 6,798 4,572 Professional fees 323 183 Other 483 196 Total $ 10,170 $ 9,522

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2020
Earnings Per Share [Abstract]
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 data): Three Months Ended March 31, 2020 2019 Numerator: Net loss $ (27,753 ) $ (17,670 ) Denominator: Weighted-average common shares outstanding 45,953,213 44,532,073 Less: weighted-average common shares subject to vesting (1,670,606 ) (1,023,481 ) Weighted-average common shares used to compute basic and diluted net loss per share 44,282,607 43,508,592 Net loss per share: basic and diluted $ (0.63 ) $ (0.41 )
Summary of Outstanding Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss per Share	The following outstanding potentially dilutive securities were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive: As of March 31, 2020 2019 Common stock options issued and outstanding 6,725,835 3,222,103 Unvested restricted common stock issued as part of collaboration agreement 1,257,651 - Unvested early exercised common stock options 375,615 811,300 Unvested restricted common stock - 115,741 Total 8,359,101 4,149,144

Organization - Additional Infor

Organization - Additional Information (Details) $ in Millions	Mar. 31, 2020USD ($)
Cash, Cash Equivalents and Investments in Marketable Securities
Class Of Stock [Line Items]
Cash and investments	$ 157.9

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Jun. 29, 2017
Accounting Policies [Abstract]
Description to be remained in emerging growth company	The Company will remain an emerging growth company until the earliest of (1) the last day of its first fiscal year (a) following the fifth anniversary of the completion of its initial public offering, (b) in which the Company has a total annual gross revenue of at least $1.07 billion, or (c) in which the Company is deemed to be a large accelerated filer, which means the market value of the common stock that is held by non-affiliates exceeds $700.0 million of the prior June 30th or (2) the date on which the Company has issued more than $1.0 billion in non-convertible debt securities during the prior three-year period.
Minimum annual gross revenue in order to remain classified as emerging growth company	$ 1,070
Maximum market value of common stock held by non-affiliates to be remained in emerging growth company		$ 700
Additional non-convertible debt securities to be remained in emerging growth company	$ 1,000

Significant Accounting Polici_5

Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019		Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash and cash equivalents	$ 67,326	$ 57,937	[1]
Restricted cash	203	203	[1]
Cash, cash equivalents and restricted cash	$ 67,529	$ 58,140		$ 68,702	$ 71,267
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2019 has been derived from the audited financial statements as of that date.

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair value assets transferred from level 1 to level 2	$ 0	$ 0
Fair value assets transferred from level 2 to level 1	0	0
Fair value liabilities transferred from level 1 to level 2	0	0
Fair value liabilities transferred from level 2 to level 1	0	0
Fair value assets transferred into level 3	0	0
Fair value assets transferred out of level 3	0	0
Fair value liabilities transferred into level 3	0	0
Fair value liabilities transferred out of level 3	0	0
Realized gains (loss) on sale or maturity of available-for-sale marketable securities	0	0
Reclassification out of accumulated other comprehensive loss	$ 0	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Instruments Measured at Fair Value on Recurring Basis (Details) - Fair Value On Recurring Basis - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 157,866	$ 188,270
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	67,326	45,498
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	90,540	142,772
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	67,326	45,498
Money Market Funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	67,326	45,498
Corporate Securities and Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	34,571	67,918
Corporate Securities and Commercial Paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	34,571	67,918
U.S. Government Treasury and Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	55,969	74,854
U.S. Government Treasury and Agency Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets measured at fair value	$ 55,969	$ 74,854

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Investments Classified as Available for Sale Securities with Contractual Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Cash and cash equivalents	$ 67,326	$ 57,937
Short-term investments (due within one year)	90,540	130,333	[1]
Total cash, cash equivalents and investments in marketable securities	$ 157,866	$ 188,270
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2019 has been derived from the audited financial statements as of that date.

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Fair Value and Amortized Cost of Investments in Marketable Securities by Major Security Type (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	$ 157,578	$ 188,270
Unrealized Gain	315	67
Unrealized Loss	(27)	(3)
Fair Value	157,866	188,334
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	67,326	45,498
Fair Value	67,326	45,498
Corporate Securities and Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	34,589	67,918
Unrealized Gain	9	55
Unrealized Loss	(27)	(2)
Fair Value	34,571	67,971
U.S. Government Treasury and Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	55,663	74,854
Unrealized Gain	306	12
Unrealized Loss		(1)
Fair Value	$ 55,969	$ 74,865

Equity Investment - Additional

Equity Investment - Additional Information (Details) - USD ($) shares in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Gain on deemed sale from equity method investee	$ 482,000	$ 0
Loss from equity method investments	482,000	431,000
PACT Pharma
Schedule of Equity Method Investments [Line Items]
Investment balance	0	0	$ 0
Gain on deemed sale from equity method investee	1,300,000
Loss from equity method investments	500,000	$ 0	$ 800,000
Gain on equity investments net of prior period losses	500,000
Unrealized loss on equity method investments	$ 100,000
PACT Pharma | Series A Preferred Stock
Schedule of Equity Method Investments [Line Items]
Purchase of common stock, shares				1
PACT Pharma | Common Stock
Schedule of Equity Method Investments [Line Items]
Purchase of common stock, shares				3.6

License and Collaboration Agr_3

License and Collaboration Agreements - Additional Information (Details)

Apr. 30, 2019USD ($)shares

Oct. 31, 2017USD ($)

Sep. 30, 2017USD ($)Program

Aug. 31, 2017USD ($)

Mar. 31, 2020USD ($)shares

Dec. 31, 2019USD ($)

Mar. 31, 2019USD ($)

Mar. 31, 2020USD ($)shares

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Mar. 31, 2020USD ($)shares

License And Collaboration Agreements [Line Items]

Revenue recognized

$ 1,750,000

$ 1,750,000

Development expense

23,142,000

15,554,000

Compensation expense recognized

3,462,000

1,674,000

Research and Development Expenses

License And Collaboration Agreements [Line Items]

Compensation expense recognized

$ 1,736,000

847,000

Taiho Pharmaceutical Co., Ltd | Taiho Agreement

License And Collaboration Agreements [Line Items]

Option period

5 years

Non refundable and non creditable cash payments

$ 35,000,000

Payment received for license agreement

$ 5,000,000

$ 5,000,000

$ 5,000,000

$ 25,000,000

Range of royalties receivable on net sales

high single-digits to mid-teens

Royalties payable description

Royalties will be payable on a licensed product-by-licensed product and country-by-country basis during the period of time commencing on the first commercial sale of a licensed product in a country and ending upon the later of: (a) ten (10) years from the date of first commercial sale of such licensed product in such country; and (b) expiration of the last-to-expire valid claim of the Company’s patents covering the manufacture, use or sale or exploitation of such licensed product in such country (the Royalty Term).

Upfront cash payment

$ 20,000,000

Non-refundable, non-creditable upfront cash payments

$ 35,000,000

Estimated performance period

5 years

Payment for first option exercise

8,000,000

$ 3,000,000

Licensing revenue recognized

8,000,000

Clinical and regulatory milestones achieved

$ 0

Sales milestone or royalty revenue recognized

0

Revenue recognized

1,800,000

$ 1,800,000

Deferred revenue, current

7,000,000

$ 7,000,000

$ 7,000,000

Deferred revenue, noncurrent

$ 10,300,000

10,300,000

10,300,000

Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Minimum

License And Collaboration Agreements [Line Items]

Number of programs, IND enabling studies not initiated | Program

5

Payment for option exercise

$ 3,000,000

Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Maximum

License And Collaboration Agreements [Line Items]

Extended option agreement period

7 years

Payment for option exercise

$ 15,000,000

Additional clinical and regulatory milestone payments receivable

130,000,000

Contingent payments receivable

$ 145,000,000

WuXi Biologics License Agreement

License And Collaboration Agreements [Line Items]

Range of tiered royalty payments on net sales

high single-digits to low teens

Development expense

$ 0

WuXi Biologics License Agreement | Research and Development Expenses

License And Collaboration Agreements [Line Items]

Upfront and milestone payments

$ 26,000,000

Sub-license fees incurred

$ 1,200,000

Sub-license fees paid

1,200,000

WuXi Biologics License Agreement | Maximum

License And Collaboration Agreements [Line Items]

Clinical, regulatory and commercialization milestone payments

$ 375,000,000

Abmuno License Agreement

License And Collaboration Agreements [Line Items]

Upfront and milestone payments

$ 6,600,000

Abmuno License Agreement | Maximum

License And Collaboration Agreements [Line Items]

Clinical, regulatory and commercialization remaining milestone payments

101,000,000

Genentech

License And Collaboration Agreements [Line Items]

Development expense

0

Strata Oncology Inc | Co-Development and Collaboration Agreement

License And Collaboration Agreements [Line Items]

Development milestone payable

$ 2,500,000

Development cost recorded within research and development expenses

400,000

1,400,000

Development cost reimbursed

$ 100,000

$ 300,000

Number of restricted shares of common stock issued | shares

1,257,651

Fair value of restricted shares of common stock issued

$ 15,000,000

Strata Oncology Inc | Co-Development and Collaboration Agreement | Non-vested Restricted Stock

License And Collaboration Agreements [Line Items]

Shares probable of vesting | shares

0

0

0

Compensation expense recognized

$ 0

Strata Oncology Inc | Co-Development and Collaboration Agreement | Research and Development Expenses

License And Collaboration Agreements [Line Items]

Milestone payments

$ 2,500,000

Strata Oncology Inc | Co-Development and Collaboration Agreement | Maximum

License And Collaboration Agreements [Line Items]

Regulatory and commercial milestone payable

$ 125,000,000

License and Collaboration Agr_4

License and Collaboration Agreements - Summary of Revenue Recognized as a Result of Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
License And Collaboration Agreements [Abstract]
Revenue recognized	$ 1,750	$ 1,750

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - shares	Jan. 31, 2020	Mar. 31, 2018
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued or transferred		3,570,000
2020 Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued or transferred	3,000,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 3,462	$ 1,674
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	1,736	847
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 1,726	$ 827

Accrued Liabilities - Summary o

Accrued Liabilities - Summary of Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accrued Liabilities Current [Abstract]
Accrued personnel expenses	$ 2,566	$ 4,571
Accrued research and development expenses	6,798	4,572
Professional fees	323	183
Other	483	196
Total	$ 10,170	$ 9,522	[1]
[1]	The Condensed Consolidated Balance Sheet as of December 31, 2019 has been derived from the audited financial statements as of that date.

Net Loss per Share - Computatio

Net Loss per Share - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Net loss	$ (27,753)	$ (17,670)
Denominator:
Weighted-average common shares outstanding	45,953,213	44,532,073
Less: weighted-average common shares subject to vesting	(1,670,606)	(1,023,481)
Weighted-average number of shares used to compute basic and diluted net loss per share	44,282,607	43,508,592
Net loss per share: basic and diluted	$ (0.63)	$ (0.41)

Net Loss per Share - Summary of

Net Loss per Share - Summary of Outstanding Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss per Share (Details) - shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	8,359,101	4,149,144
Common Stock Options Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	6,725,835	3,222,103
Unvested Restricted Stock Issued as Part of Collaboration Agreement
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	1,257,651
Unvested Early Exercised Common Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share	375,615	811,300
Unvested Restricted Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of diluted net loss per share		115,741