Jounce Therapeutics (JNCE) 10-Q 5 Aug 21 2021 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2021	Jul. 30, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	001-37998
Entity Registrant Name	JOUNCE THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-4870634
Entity Address, Address Line One	780 Memorial Drive
Entity Address, City or Town	Cambridge,
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02139
City Area Code	857
Local Phone Number	259-3840
Title of 12(b) Security	Common Stock, $0.001 par value per share
Trading Symbol	JNCE
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		51,232,029
Entity Central Index Key	0001640455
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 140,814	$ 147,493
Short-term investments	79,319	58,985
Accounts receivable — related party	24,976	31
Prepaid expenses and other current assets	12,010	4,882
Total current assets	257,119	211,391
Property and equipment, net	6,026	7,336
Long-term investments	26,015	6,710
Operating lease right-of-use asset	13,403	14,856
Other non-current assets	3,597	3,943
Total assets	306,160	244,236
Current liabilities:
Accounts payable	2,476	2,036
Accrued expenses	9,853	12,044
Deferred revenue, current — related party	0	1,931
Operating lease liability, current	3,478	3,271
Other current liabilities	34	42
Total current liabilities	15,841	19,324
Operating lease liability, net of current portion	11,857	13,618
Total liabilities	27,698	32,942
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value: 5,000 shares authorized at June 30, 2021 and December 31, 2020; no shares issued or outstanding at June 30, 2021 or December 31, 2020	0	0
Common stock, $0.001 par value: 160,000 shares authorized at June 30, 2021 and December 31, 2020; 51,221 and 41,729 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	51	42
Additional paid-in capital	459,982	362,270
Accumulated other comprehensive income	(24)	(17)
Accumulated deficit	(181,547)	(151,001)
Total stockholders’ equity	278,462	211,294
Total liabilities and stockholders’ equity	$ 306,160	$ 244,236

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock (in dollars per share)	$ 0.001	$ 0.001
Preferred stock shares authorized (in shares)	5,000,000	5,000,000
Preferred stock shares issued (in shares)	0	0
Preferred stock shares outstanding (in shares)	0	0
Common stock (in dollars per share)	$ 0.001	$ 0.001
Common stock shares authorized (in shares)	160,000,000	160,000,000
Common stock shares issued (in shares)	51,221,000	41,729,000
Common stock shares outstanding (in shares)	51,221,000	41,729,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
License and collaboration revenue — related party	$ 25,368	$ 0	$ 26,907	$ 0
Operating expenses:
Research and development	22,100	21,023	42,607	40,669
General and administrative	7,317	7,226	14,932	14,765
Total operating expenses	29,417	28,249	57,539	55,434
Operating loss	(4,049)	(28,249)	(30,632)	(55,434)
Other income, net	40	285	89	1,035
Loss before provision for income taxes	(4,009)	(27,964)	(30,543)	(54,399)
Provision for income taxes	2	4	3	12
Net loss	$ (4,011)	$ (27,968)	$ (30,546)	$ (54,411)
Net loss per share, basic (in dollars per share)	$ (0.08)	$ (0.82)	$ (0.63)	$ (1.60)
Net loss per share, diluted (in dollars per share)	$ (0.08)	$ (0.82)	$ (0.63)	$ (1.60)
Weighted-average common shares outstanding, basic (in shares)	51,212	34,053	48,601	34,041
Weighted-average common shares outstanding, diluted (in shares)	51,212	34,053	48,601	34,041
Comprehensive loss:
Net loss	$ (4,011)	$ (27,968)	$ (30,546)	$ (54,411)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities	1	(11)	(7)	79
Comprehensive loss	$ (4,010)	$ (27,979)	$ (30,553)	$ (54,332)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	At The Market Offering	Follow-on Public Offering	Common Stock	Common StockAt The Market Offering	Common StockFollow-on Public Offering	Additional Paid-In Capital	Additional Paid-In CapitalAt The Market Offering	Additional Paid-In CapitalFollow-on Public Offering	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Beginning balance, common stock (in shares) at Dec. 31, 2019				33,738
Beginning balance at Dec. 31, 2019	$ 174,593			$ 34			$ 281,664			$ 54	$ (107,159)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from, net of issuance costs (in shares)					201
Issuance of common stock, net of issuance costs		$ 1,648						$ 1,648
Exercises of common stock options (in shares)				9
Exercises of common stock options	38						38
Vesting of restricted stock units (in shares)				101
Vesting of restricted stock units	0						0
Stock-based compensation expense	2,618						2,618
Other comprehensive income (loss)	90									90
Net loss	(26,443)										(26,443)
Ending balance (in shares) at Mar. 31, 2020				34,049
Ending balance at Mar. 31, 2020	152,544			$ 34			285,968			144	(133,602)
Beginning balance, common stock (in shares) at Dec. 31, 2019				33,738
Beginning balance at Dec. 31, 2019	174,593			$ 34			281,664			54	(107,159)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	79
Net loss	(54,411)
Ending balance (in shares) at Jun. 30, 2020				34,065
Ending balance at Jun. 30, 2020	127,269			$ 34			288,672			133	(161,570)
Beginning balance, common stock (in shares) at Mar. 31, 2020				34,049
Beginning balance at Mar. 31, 2020	152,544			$ 34			285,968			144	(133,602)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)				16
Exercises of common stock options	61						61
Stock-based compensation expense	2,643						2,643
Other comprehensive income (loss)	(11)									(11)
Net loss	(27,968)										(27,968)
Ending balance (in shares) at Jun. 30, 2020				34,065
Ending balance at Jun. 30, 2020	$ 127,269			$ 34			288,672			133	(161,570)
Beginning balance, common stock (in shares) at Dec. 31, 2020	41,729			41,729
Beginning balance at Dec. 31, 2020	$ 211,294			$ 42			362,270			(17)	(151,001)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock from, net of issuance costs (in shares)					3,156	5,750
Issuance of common stock, net of issuance costs		$ 30,221	$ 60,638		$ 3	$ 6		$ 30,218	$ 60,632
Exercises of common stock options (in shares)				342
Exercises of common stock options	1,019						1,019
Vesting of restricted stock units (in shares)				223
Stock-based compensation expense	2,825						2,825
Other comprehensive income (loss)	(8)									(8)
Net loss	(26,535)										(26,535)
Ending balance (in shares) at Mar. 31, 2021				51,200
Ending balance at Mar. 31, 2021	$ 279,454			$ 51			456,964			(25)	(177,536)
Beginning balance, common stock (in shares) at Dec. 31, 2020	41,729			41,729
Beginning balance at Dec. 31, 2020	$ 211,294			$ 42			362,270			(17)	(151,001)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)	363
Other comprehensive income (loss)	$ (7)
Net loss	$ (30,546)
Ending balance (in shares) at Jun. 30, 2021	51,221			51,221
Ending balance at Jun. 30, 2021	$ 278,462			$ 51			459,982			(24)	(181,547)
Beginning balance, common stock (in shares) at Mar. 31, 2021				51,200
Beginning balance at Mar. 31, 2021	279,454			$ 51			456,964			(25)	(177,536)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercises of common stock options (in shares)				21
Exercises of common stock options	83						83
Stock-based compensation expense	2,935						2,935
Other comprehensive income (loss)	1									1
Net loss	$ (4,011)										(4,011)
Ending balance (in shares) at Jun. 30, 2021	51,221			51,221
Ending balance at Jun. 30, 2021	$ 278,462			$ 51			$ 459,982			$ (24)	$ (181,547)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities:
Net loss	$ (30,546)	$ (54,411)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	5,760	5,261
Depreciation expense	1,501	1,795
Net amortization of premiums and discounts on investments	338	(95)
Other non-cash items	0	(4)
Changes in operating assets and liabilities:
Accounts receivable — related party	(24,945)	0
Prepaid expenses and other current assets	(7,126)	745
Other non-current assets	345	(128)
Accounts payable	473	741
Accrued expenses and other current liabilities	(2,232)	1,181
Deferred revenue — related party	(1,931)	0
Other liabilities	(101)	(61)
Net cash used in operating activities	(58,464)	(44,976)
Investing activities:
Purchases of investments	(78,565)	(30,752)
Proceeds from maturities of investments	38,581	95,387
Purchases of property and equipment	(157)	(50)
Net cash (used in) provided by investing activities	(40,141)	64,585
Financing activities:
Proceeds from at the market offering, net of issuance costs	90,826	1,514
Proceeds from exercise of stock options	1,100	99
Net cash provided by financing activities	91,926	1,613
Net increase (decrease) in cash, cash equivalents and restricted cash	(6,679)	21,222
Cash, cash equivalents and restricted cash, beginning of period	148,763	54,511
Cash, cash equivalents and restricted cash, end of period	142,084	75,733
Non-cash investing and financing activities:
Purchases of property and equipment in accounts payable and accrued expenses	33	0
Stock option exercise receivables in prepaid expenses and other current assets	2	0
Supplemental cash flow information:
Cash paid for lease liabilities	2,626	2,190
Cash paid for income taxes	$ 8	$ 45

Nature of Business

Nature of Business	6 Months Ended
	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	Nature of Business Jounce Therapeutics, Inc. (the “Company”) is a clinical-stage immunotherapy company dedicated to transforming the treatment of cancer by developing therapies that enable the immune system to attack tumors and provide long-lasting benefits to patients through a biomarker-driven approach. The Company is subject to a number of risks similar to those of other clinical-stage companies, including dependence on key individuals; the need to develop commercially viable products; competition from other companies, many of which are larger and better capitalized; and the need to obtain adequate additional financing to fund the development of its products. As of June 30, 2021, the Company had cash, cash equivalents and investments of $246.1 million. The Company expects that its existing cash, cash equivalents and investments will enable it to fund its expected operating expenses and capital expenditure requirements for at least 12 months from August 5, 2021, the filing date of this Quarterly Report on Form 10-Q. The Company expects to finance its future cash needs through a combination of equity or debt financings, collaborations, licensing arrangements and strategic alliances.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements as of June 30, 2021 and December 31, 2020, and for the three and six months ended June 30, 2021 and 2020, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and generally accepted accounting principles in the United States of America (“GAAP”) as found in the Accounting Standards Codification (“ASC”) of the Financial Accounting Standards Board (“FASB”) for condensed consolidated financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, these condensed consolidated financial statements reflect all normal recurring adjustments which are necessary for a fair presentation of the Company’s financial position and results of its operations, as of and for the periods presented. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC on February 25, 2021 (the “Annual Report on Form 10-K”). The information presented in the condensed consolidated financial statements and related notes as of June 30, 2021, and for the three and six months ended June 30, 2021 and 2020, is unaudited. The December 31, 2020 condensed consolidated balance sheet included herein was derived from the audited financial statements as of that date, but does not include all disclosures, including notes, required by GAAP for complete financial statements. Interim results for the six months ended June 30, 2021 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2021, or any future period. The accompanying condensed consolidated financial statements include the accounts of Jounce Therapeutics, Inc. and its wholly-owned subsidiary, Jounce Mass Securities, Inc. All intercompany transactions and balances have been eliminated in consolidation. Summary of Significant Accounting Policies The significant accounting policies and estimates used in the preparation of the condensed consolidated financial statements are described in the Company’s audited financial statements as of and for the year ended December 31, 2020, and the notes thereto, which are included in the Annual Report on Form 10-K. There have been no material changes in the Company’s significant accounting policies during the six months ended June 30, 2021. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates which include, but are not limited to, accrued expenses, stock-based compensation expense and income taxes. The Company bases its estimates on historical experience and other market specific or other relevant assumptions it believes to be reasonable under the circumstances. Actual results could differ from those estimates. In June 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . This standard requires that credit losses be reported using an expected losses model rather than the incurred losses model that is currently used, and it establishes additional disclosure requirements related to credit risks. For available-for-sale debt securities with expected credit losses, this standard now requires allowances to be recorded instead of reducing the amortized cost of the investment. This guidance was originally effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption was permitted. In November 2019, the FASB subsequently issued ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates

License and Collaboration Reven

License and Collaboration Revenue	6 Months Ended
	Jun. 30, 2021
Revenue from Contract with Customer [Abstract]
License and Collaboration Revenue	License and Collaboration Revenue Gilead License Agreement On August 31, 2020, the Company and Gilead Sciences, Inc. (“Gilead”) entered into an exclusive license agreement (the “Gilead License Agreement”) to license the Company’s JTX-1811 program to Gilead, which will be referred to as GS-1811 in Gilead’s pipeline. Concurrently with the license agreement, the Company and Gilead entered into a stock purchase agreement (the “Stock Purchase Agreement”) and a registration rights agreement (the “Registration Rights Agreement”, and together with the License Agreement and the Stock Purchase Agreement, the “Transaction Agreements”). Pursuant to the Gilead License Agreement, the Company granted to Gilead a worldwide and exclusive license to develop, manufacture and commercialize JTX-1811 and certain derivatives thereof (the “Licensed Products”). Gilead paid the Company a one-time, non-refundable upfront payment of $85.0 million pursuant to the Gilead License Agreement and the Company sold Gilead 5,539,727 shares of common stock pursuant to the Stock Purchase Agreement for proceeds of $35.0 million upon the closing in October 2020. The Company continued to develop JTX-1811 during the initial development term, which included conducting activities defined within the agreement to advance JTX-1811 through the clearance of an investigational new drug application (“IND”), which occurred in June 2021, at which time the program transitioned to Gilead. Milestone and Royalties The Company is entitled to receive payments from Gilead upon the achievement of specified clinical, regulatory and sales milestones, including potential clinical development and regulatory milestone payments up to an aggregate total of $510.0 million and potential sales milestone payments up to an aggregate total of $175.0 million. The Company is also eligible to receive tiered royalty payments based on a percentage of annual worldwide net sales ranging from the high-single digits to mid-teens, based on future annual net sales of the Licensed Products, on a Licensed Product-by-Licensed Product and country-by-country basis. In June 2021, the Company received clearance of the IND for JTX-1811 from the U.S. Food and Drug Administration (“FDA”) and achieved a $25.0 million milestone under the Gilead License Agreement. Payment for this milestone was received in July 2021. Termination Gilead may terminate the License Agreement for convenience, at its sole discretion, in its entirety or on a Licensed Product-by-Licensed Product or region-by-region basis, at any time with prior written notice to the Company. Unless terminated earlier in accordance with its terms, the Gilead License Agreement provides that it will expire (i) on a Licensed Product-by-Licensed Product and country-by-country basis on the date of the expiration of the royalty term with respect to such Licensed Product in such country and (ii) in its entirety upon the expiration of all applicable royalty terms with respect to the Licensed Products in all countries, following which the applicable licenses under the Gilead License Agreement will become fully paid-up, perpetual, irrevocable and royalty-free. Accounting Analysis Identification of the Contract(s) The Company assessed the Gilead License Agreement and concluded that it represents a contract with a customer within the scope of ASC 606, Revenue from Contracts with Customers (“ASC 606”). In addition, the Company determined that the Gilead License Agreement and Stock Purchase Agreement should be evaluated as a combined contract in accordance with ASC 606 given that the agreements were executed contemporaneously, negotiated as a package and have the same commercial objective to provide funding to further the Company’s research and development activities. Identification of Promises and Performance Obligations The Company determined that the Gilead License Agreement contains the following promises: (i) delivery of a worldwide and exclusive license to develop, manufacture and commercialize JTX-1811 (the “JTX-1811 License”), (ii) provision of certain research transition activities, specifically outlined within the Gilead License Agreement, related to the advancement of JTX-1811 through the clearance of an IND and transition of the JTX-1811 program to Gilead (the “Research and Transition Services”), (iii) appointment of an individual to act as an alliance manager and primary point of contact for Gilead, (iv) appointment of individuals to participate on the Joint Steering Committee (“JSC”), and (v) optional assistance by Jounce after completion of Research and Transition Services upon the request of Gilead. The Company assessed the above promises and concluded that each of the JTX-1811 License and Research and Transition Services is capable of being distinct and distinct within the context of the Gilead License Agreement. Based upon this evaluation, the Company concluded that its promise to deliver the JTX-1811 License and promise to perform Research and Transition Services represent separate performance obligations in the Gilead License Agreement. The Company determined that the appointment of an individual to act as an alliance manager and primary point of contact for Gilead, participation in alliance management meetings and the appointment of individuals to participate on the JSC do not constitute the transfer of a good or service to Gilead and as such, do not represent performance obligations under the contract. Finally, the Company assessed Gilead’s ability to request optional assistance by Jounce after completion of Research and Transition Services and determined that it was both quantitatively and qualitatively immaterial in the context of the Gilead License Agreement. Accordingly, the Company did not assess the optional assistance as a performance obligation. Determination of Transaction Price As noted above, the Company received a non-refundable upfront payment of $85.0 million upon the closing of the Gilead License Agreement. This upfront payment represents an element of fixed consideration under the Gilead License Agreement. The Company also evaluated as possible variable consideration the milestones and royalties discussed above. With respect to clinical development and regulatory milestones, based upon the high degree of uncertainty and risk associated with these potential payments, the Company concluded that all such amounts should be fully constrained and are not included in the initial transaction price. As part of the evaluation of the constraint the Company considered certain factors, including that receipt of such milestones is outside the control of the Company and the probability of success criteria is estimated. Each of these variable consideration items was evaluated under the most-likely amount method. As for royalties and sales milestones, the Company determined that the royalties and milestones relate solely to the JTX-1811 License, which is a license of intellectual property (“IP”). Accordingly, the Company did not include any potential royalty or sales milestone amounts in the initial transaction price, and the Company will not recognize revenue related to these royalties and sales milestones until the associated sales occur and relevant thresholds are met. The Company will re-evaluate the transaction price in each reporting period as uncertain events are resolved or as other changes in circumstances occur, and if necessary, will adjust its estimate of the transaction price to include milestones as they become probable of occurrence. The Company assessed proceeds of $35.0 million received under the Stock Purchase Agreement and determined that the fair value of the equity component was $55.7 million based on the closing price of $10.06 per share in October 2020. Pursuant to the agreement, the Company sold 5,539,727 shares of common stock for aggregate cash consideration of $35.0 million, or $6.32 per share, which is equal to the daily volume weighted average per share intraday price of the Common Stock on Nasdaq over the 30-trading day period ending on and including August 28, 2020 plus a 30% premium. As a result, the Company determined that the gross proceeds of $35.0 million received under the Stock Purchase Agreement included a discount to the fair value of the Company’s stock as of October 16, 2020 equal to $20.7 million. In accordance with ASC 606, the discount amount will be included in the transaction price for revenue recognition, resulting in an initial transaction price of $64.3 million. Allocation of Transaction Price to Performance Obligations The Company allocated the transaction price to each performance obligation on a relative estimated standalone selling price basis. The Company developed the estimated standalone selling price for the JTX-1811 License based on the present value of expected future cash flows associated with the license and related clinical development and regulatory milestones. In developing such estimate, the Company applied judgement in determining the timing needed to develop the Licensed Product, the probability of success, and the discount rate. The Company developed the estimated standalone selling price for the Research and Transition Services obligation based on the nature of the services to be performed and the Company’s best estimate of the length of time required to perform the services necessary to achieve clearance of an IND for the JTX-1811 program. Based on the above considerations, $60.8 million of the initial transaction price was allocated to the JTX-1811 License performance obligation and $3.5 million was allocated to the Research and Transition Services performance obligation. Recognition of Revenue The Company determined that the JTX-1811 License is a functional license as the underlying IP has significant standalone functionality. In addition, the Company determined that the JTX-1811 License represents a right to use certain of the Company’s IP as it exists at a point in time. Finally, the Company determined that October 16, 2020 represents (i) the date at which the Company made available the IP to Gilead and (ii) the beginning of the period during which Gilead is able to use and benefit from its right to use the IP. Based upon these considerations, the Company recognized the entirety of the initial transaction price allocated to the JTX-1811 License performance obligation during the year ended December 31, 2020. Further, the Company determined the input method under ASC 606 is the most appropriate method of revenue recognition for the Research and Transition Services performance obligation. The method of measuring progress towards delivery of the services incorporated actual internal and external costs incurred, relative to total internal and external costs expected to be incurred to satisfy the performance obligation. The period over which total costs were estimated reflected the Company’s best estimate of the period over which it would perform the research and transition services to achieve clearance of an IND of the JTX-1811 program and transition the program to Gilead. During the three months ended June 30, 2021, the Company recognized $25.4 million in collaboration and license revenue under the Gilead License Agreement, $25.0 million of which was recognized related to the achievement of a clinical development and regulatory milestone for FDA clearance of the IND for JTX-1811 and $0.4 million of which related to the performance of research and transition services. No revenue was recognized during the three months ended June 30, 2020. During the six months ended June 30, 2021, the Company recognized $26.9 million in collaboration and license revenue under the Gilead License Agreement, $25.0 million of which related to the achievement of a clinical development and regulatory milestone for FDA clearance of the IND for JTX-1811 and $1.9 million of which related to the performance of research and transition services. No revenue was recognized during the six months ended June 30, 2020. As of June 30, 2021 and December 31, 2020, receivables due from Gilead of $25.0 million and less than $0.1 million, respectively, were included in “Accounts receivable — related party”. The Company subsequently received payment for the $25.0 million milestone in July 2021. The following table presents changes in the Company’s contract liabilities related to the Gilead License Agreement during the six months ended June 30, 2021 (in thousands): January 1, 2021 Additions Reductions June 30, 2021 Contract liabilities: Deferred revenue — related party 1,931 — (1,931) — Total $ 1,931 $ — $ (1,931) $ — The reductions to deferred revenue - related party during the six months ended June 30, 2021 were comprised of revenue recognized for research and transition services performed during the period.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value is an exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value is determined based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect certain market assumptions. As a basis for considering such assumptions, GAAP establishes a three-tier value hierarchy, which prioritizes the inputs used to develop the assumptions and for measuring fair value as follows: (Level 1) observable inputs such as quoted prices in active markets for identical assets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. The Company measures the fair value of money market funds, U.S. Treasuries and government agency securities based on quoted prices in active markets for identical securities. Investments also include corporate debt securities which are valued either based on recent trades of securities in inactive markets or based on quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data. The carrying amounts reflected in the condensed consolidated balance sheets for cash, prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values, due to their short-term nature. Assets measured at fair value on a recurring basis as of June 30, 2021 were as follows (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Money market funds, included in cash equivalents $ 140,814 $ 140,814 $ — $ — Investments: Corporate debt securities 95,165 — 95,165 — U.S. Treasuries 7,486 7,486 — — Government agency securities 2,683 — 2,683 — Totals $ 246,148 $ 148,300 $ 97,848 $ — Assets measured at fair value on a recurring basis as of December 31, 2020 were as follows (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Money market funds, included in cash equivalents $ 147,492 $ 147,492 $ — $ — Investments: Corporate debt securities 63,691 — 63,691 — Government agency securities 2,005 — 2,005 — Totals $ 213,188 $ 147,492 $ 65,696 $ — There were no changes in valuation techniques during the six months ended June 30, 2021 or during the year ended December 31, 2020. There were no liabilities measured at fair value on a recurring basis as of June 30, 2021 or December 31, 2020.

Investments

Investments	6 Months Ended
	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Investments	InvestmentsShort-term investments consist of investments with maturities greater than ninety days and less than one year from the balance sheet date. Long-term investments consist of investments with maturities of greater than one year that are not expected to be used to fund current operations. The Company classifies all of its investments as available-for-sale securities. Accordingly, these investments are recorded at fair value. Realized gains and losses, amortization and accretion of discounts and premiums are included in other income, net. Unrealized gains and losses on available-for-sale securities are included in other comprehensive income as a component of stockholders’ equity until realized. Cash equivalents, short-term investments and long-term investments as of June 30, 2021 were comprised as follows (in thousands): June 30, 2021 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 140,814 $ — $ — $ 140,814 Corporate debt securities 79,316 6 (3) 79,319 Total cash equivalents and short-term investments $ 220,130 $ 6 $ (3) $ 220,133 Long-term investments: Corporate debt securities 15,868 — (22) 15,846 U.S. Treasuries 7,487 — (1) 7,486 Government agency securities 2,687 — (4) 2,683 Total long-term investments 26,042 — (27) 26,015 Total cash equivalents and investments $ 246,172 $ 6 $ (30) $ 246,148 Cash equivalents, short-term investments and long-term investments as of December 31, 2020 were comprised as follows (in thousands): December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 147,492 $ — $ — $ 147,492 Corporate debt securities 56,985 9 (13) 56,981 Government agency securities 2,001 4 — 2,005 Total cash equivalents and short-term investments 206,478 13 (13) 206,478 Long-term investments: Corporate debt securities 6,727 — (17) 6,710 Total long-term investments 6,727 — (17) 6,710 Total cash equivalents and investments $ 213,205 $ 13 $ (30) $ 213,188 As of June 30, 2021 and December 31, 2020, the aggregate fair value of securities that were in an unrealized loss position for less than twelve months was $39.8 million and $28.3 million, respectively. There were no securities that were in an unrealized loss position for more than twelve months as of either June 30, 2021 or December 31, 2020. As of June 30, 2021, the Company did not intend to sell, and would not be more likely than not required to sell, the securities in an unrealized loss position before recovery of their amortized cost bases. Furthermore, the Company determined that there was no material change in the credit risk of these securities. As a result, the Company determined it did not hold any securities with any other-than-temporary impairment as of June 30, 2021. There were no realized gains or losses on available-for-sale securities during the three or six months ended June 30, 2021. There were immaterial realized gains on available-for-sale securities during the three and six months ended June 30, 2020.

Restricted Cash

Restricted Cash	6 Months Ended
	Jun. 30, 2021
Cash and Cash Equivalents [Abstract]
Restricted Cash	Restricted CashAs of both June 30, 2021 and December 31, 2020, the Company maintained non-current restricted cash of $1.3 million. This amount is included within “Other non-current assets” in the accompanying condensed consolidated balance sheets and is comprised solely of a letter of credit required pursuant to the lease for the Company’s corporate headquarters. The following table provides a reconciliation of cash, cash equivalents and restricted cash that sums to the total of the same such amounts shown in the condensed consolidated statements of cash flows (in thousands): Six Months Ended Six Months Ended Beginning of Period End of Period Beginning of Period End of Period Cash and cash equivalents $ 147,493 $ 140,814 $ 53,241 $ 74,463 Restricted cash 1,270 1,270 1,270 1,270 Cash, cash equivalents and restricted cash $ 148,763 $ 142,084 $ 54,511 $ 75,733

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2021
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses as of June 30, 2021 and December 31, 2020 were comprised as follows (in thousands): June 30, December 31, 2021 2020 External research and development and professional services $ 4,973 $ 4,855 Employee compensation and benefits 4,453 6,825 Lab consumables and other 427 364 Total accrued expenses $ 9,853 $ 12,044

Common Stock and Preferred Stoc

Common Stock and Preferred Stock	6 Months Ended
	Jun. 30, 2021
Equity [Abstract]
Common Stock and Preferred Stock	Common Stock and Preferred Stock Common Stock The Company is authorized to issue 160,000,000 shares of common stock. Holders of common stock are entitled to one vote per share. Holders of common stock are entitled to receive dividends, if and when declared by the board of directors. On December 17, 2019, the Company entered into a Sales Agreement with Cowen and Company, LLC, or Cowen, pursuant to which the Company offered and sold shares of its common stock with an aggregate offering price of up to $50.0 million under an “at the market” offering program (the “ATM Offering”). The Sales Agreement provided that Cowen would be entitled to a sales commission equal to 3.0% of the gross sales price per share of all shares sold under the ATM Offering. During the first quarter of 2021, the Company sold an aggregate of 3,156,200 shares of common stock at an average price of $9.87 per share under the ATM Offering for net proceeds of $30.2 million, which completed the sale of all available amounts under the ATM Offering. In addition, during the first quarter of 2021, the Company completed a follow-on public offering of its common stock, selling an aggregate of 5,750,000 shares of common stock at a public offering price of $11.25 per share for net proceeds of $60.6 million, after deducting underwriting discounts and commissions and offering fees. Preferred Stock The Company is authorized to issue 5,000,000 shares of undesignated preferred stock in one or more series. As of June 30, 2021, no shares of preferred stock were issued or outstanding. Shares Reserved for Future Issuance As of June 30, 2021 and December 31, 2020, the Company had reserved for future issuance the following number of shares of common stock (in thousands): June 30, December 31, 2021 2020 Shares reserved for vesting of restricted stock units 802 588 Shares reserved for exercises of outstanding stock options 7,476 6,586 Shares reserved for future issuance under the 2017 Stock Option and Incentive Plan 1,486 1,284 Total shares reserved for future issuance 9,764 8,458

Stock-based Compensation

Stock-based Compensation	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Stock-based Compensation	Stock-based Compensation 2013 Stock Option and Grant Plan In February 2013, the board of directors adopted and the Company’s stockholders approved the 2013 Stock Option and Grant Plan (the “2013 Plan”), as amended and restated, under which it could grant incentive stock options (“ISOs”), non-qualified stock options, restricted stock awards (“RSAs”) and restricted stock units (“RSUs”) to eligible employees, officers, directors, and consultants. The 2013 Plan was subsequently amended in January 2015, April 2015, July 2015, March 2016 and October 2016 to allow for the issuance of additional shares of common stock. 2017 Stock Option and Incentive Plan In January 2017, the board of directors adopted and the Company’s stockholders approved the 2017 Stock Option and Incentive Plan (the “2017 Plan”). Upon the adoption of the 2017 Plan, no further awards will be granted under the 2013 Plan. The 2017 Plan provides for the grant of ISOs, non-qualified stock options, RSAs, RSUs, stock appreciation rights and other stock-based awards. The Company’s employees, officers, directors and consultants and advisors are eligible to receive awards under the 2017 Plan. The terms of awards, including vesting requirements, are determined by the board of directors, subject to the provisions of the 2017 Plan. The Company initially registered on Form S-8 1,753,758 shares of common stock under the 2017 Plan, which was comprised of (i) 1,510,000 shares of common stock reserved for issuance under the 2017 Plan, plus (ii) 243,758 shares of common stock originally reserved for issuance under the 2013 Plan that became available for issuance under the 2017 Plan upon the completion of the Company’s IPO. The 2017 Plan also provides that an additional number of shares will automatically be added to the shares authorized for issuance under the 2017 Plan on January 1, 2018 and each January 1 st thereafter. The number of shares added each year will be equal to the lesser of (i) 4% of the outstanding shares on the immediately preceding December 31 st or (ii) such amount as determined by the compensation committee of the board of directors. Effective January 1, 2020 and 2021, 1,349,526 and 1,669,162 additional shares, respectively, were automatically added to the shares authorized for issuance under the 2017 Plan. As of June 30, 2021, there were 1,485,743 shares available for future issuance under the 2017 Plan. Inducement Stock Options The Company may grant, upon approval by the compensation committee of the board of directors, options to purchase shares of common stock as an inducement to employment in accordance with Nasdaq Listing Rule 5635(c)(4). The securities are issued pursuant to Section 4(a)(2) under the Securities Act of 1933, as amended, relating to transactions by an issuer not involving any public offering. These options are subject to substantially the same terms of the 2017 Plan. During the three months ended June 30, 2021, the Company granted an option to purchase 225,000 shares of common stock as an inducement award. 2017 Employee Stock Purchase Plan In January 2017, the board of directors adopted and the Company’s stockholders approved the 2017 Employee Stock Purchase Plan (the “2017 ESPP”). The Company initially reserved 302,000 shares of common stock for future issuance under the 2017 ESPP. The 2017 ESPP also provides that an additional number of shares will automatically be added to the shares authorized for issuance under the 2017 ESPP on January 1, 2018 and each January 1 st thereafter through January 1, 2027. The number of shares added each year will be equal to the lesser of (i) 1% of the outstanding shares on the immediately preceding December 31 st , (ii) 603,000 shares or (iii) such amount as determined by the compensation committee of the board of directors. Effective January 1, 2020 and 2021, 337,381 and 417,291 additional shares, respectively, were automatically added to the shares authorized for issuance under the 2017 ESPP. No offering periods under the 2017 ESPP had been initiated as of June 30, 2021. Stock-based Compensation Expense Total stock-based compensation expense recognized in the condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2021 and 2020 was as follows (in thousands): Three Months Ended Six Months Ended 2021 2020 2021 2020 Research and development $ 1,286 $ 1,196 $ 2,501 $ 2,377 General and administrative 1,649 1,447 3,259 2,884 Total stock-based compensation expense $ 2,935 $ 2,643 $ 5,760 $ 5,261 RSU Activity The Company has also granted RSUs to its employees under the 2017 Plan. The following table summarizes RSU activity for the six months ended June 30, 2021 (in thousands, except per share amounts): RSUs Weighted-Average Grant Date Fair Value per Share Unvested as of December 31, 2020 588 $ 5.82 Issued 472 $ 11.90 Vested (223) $ 5.64 Cancelled (35) $ 8.65 Unvested as of June 30, 2021 802 $ 9.33 No RSUs vested during the three months ended June 30, 2021 or 2020. The aggregate fair value of RSUs that vested during the six months ended June 30, 2021 and 2020, based upon the fair values of the stock underlying the RSUs on the day of vesting, was $1.5 million and $0.8 million, respectively. As of June 30, 2021, there was unrecognized stock-based compensation expense related to unvested RSUs of $6.0 million, which the Company expects to recognize over a weighted-average period of approximately 2.0 years. Stock Option Activity The fair value of stock options granted during the three and six months ended June 30, 2021 and 2020 was calculated on the date of grant using the following weighted-average assumptions: Three Months Ended Six Months Ended 2021 2020 2021 2020 Risk-free interest rate 1.1 % 0.4 % 0.8 % 1.3 % Expected dividend yield — % — % — % — % Expected term (in years) 5.9 5.6 6.0 6.0 Expected volatility 82.5 % 75.4 % 81.8 % 72.0 % Using the Black-Scholes option pricing model, the weighted-average grant date fair value of stock options granted during the three months ended June 30, 2021 and 2020 was $6.21 per share and $4.15 per share, respectively. The weighted-average grant date fair value of stock options granted during the six months ended June 30, 2021 and 2020 was $7.63 per share and $4.22 per share, respectively. The following table summarizes stock option activity during the six months ended June 30, 2021 (in thousands, except per share amounts): Options Weighted-Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at December 31, 2020 6,586 $ 8.30 6.5 $ 13,110 Granted 1,475 $ 11.03 Exercised (363) $ 3.04 Cancelled (222) $ 11.58 Outstanding at June 30, 2021 7,476 $ 9.00 6.8 $ 10,719 Exercisable at June 30, 2021 4,680 $ 8.75 5.6 $ 9,239 The aggregate intrinsic value of stock options exercised during each of the three months ended June 30, 2021 and 2020 was less than $0.1 million. The aggregate intrinsic value of stock options exercised during each of the six months ended June 30, 2021 and 2020 was $2.9 million and less than $0.1 million, respectively. As of June 30, 2021, there was unrecognized stock-based compensation expense related to unvested stock options of $15.6 million, which the Company expects to recognize over a weighted-average period of approximately 2.5 years.

Related-party Transactions

Related-party Transactions	6 Months Ended
	Jun. 30, 2021
Related Party Transactions [Abstract]
Related-party Transactions	Related-party TransactionsIn August 2020, the Company entered into the Gilead License Agreement and Stock Purchase Agreement under which it received a non-refundable upfront payment of $85.0 million and cash consideration of $35.0 million for Gilead’s purchase of 5,539,727 shares of the Company’s common stock. As of June 30, 2021, the Company had a $25.0 million receivable due from Gilead for the achievement of a clinical development and regulatory milestone under the Gilead License Agreement during the period and payment was subsequently received in July 2021. As of December 31, 2020, the Company had recorded less than $0.1 million of reimbursable expenses due from Gilead within accounts receivable in the accompanying consolidated balance sheets.

Net Loss per Share

Net Loss per Share	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Net Loss per Share	Net Loss per Share For purposes of the diluted net loss per share calculation, outstanding stock options and unvested RSUs are considered to be potentially dilutive securities, however the following weighted-average amounts were excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive (in thousands): Three Months Ended Six Months Ended 2021 2020 2021 2020 Outstanding stock options 7,332 6,670 7,143 6,504 Unvested RSUs 809 754 745 689 Total 8,141 7,424 7,888 7,193

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	The accompanying condensed consolidated financial statements as of June 30, 2021 and December 31, 2020, and for the three and six months ended June 30, 2021 and 2020, have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”) and generally accepted accounting principles in the United States of America (“GAAP”) as found in the Accounting Standards Codification (“ASC”) of the Financial Accounting Standards Board (“FASB”) for condensed consolidated financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, these condensed consolidated financial statements reflect all normal recurring adjustments which are necessary for a fair presentation of the Company’s financial position and results of its operations, as of and for the periods presented. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC on February 25, 2021 (the “Annual Report on Form 10-K”). The information presented in the condensed consolidated financial statements and related notes as of June 30, 2021, and for the three and six months ended June 30, 2021 and 2020, is unaudited. The December 31, 2020 condensed consolidated balance sheet included herein was derived from the audited financial statements as of that date, but does not include all disclosures, including notes, required by GAAP for complete financial statements.
Principles of Consolidation	The accompanying condensed consolidated financial statements include the accounts of Jounce Therapeutics, Inc. and its wholly-owned subsidiary, Jounce Mass Securities, Inc. All intercompany transactions and balances have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company’s management evaluates its estimates which include, but are not limited to, accrued expenses, stock-based compensation expense and income taxes. The Company bases its estimates on historical experience and other market specific or other relevant assumptions it believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements, Not Yet Adopted In June 2016, the FASB issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . This standard requires that credit losses be reported using an expected losses model rather than the incurred losses model that is currently used, and it establishes additional disclosure requirements related to credit risks. For available-for-sale debt securities with expected credit losses, this standard now requires allowances to be recorded instead of reducing the amortized cost of the investment. This guidance was originally effective for annual reporting periods beginning after December 15, 2019, including interim periods within those annual reporting periods, and early adoption was permitted. In November 2019, the FASB subsequently issued ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates
Fair Value Measurement Policy	Fair value is an exit price, representing the amount that would be received from the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. Fair value is determined based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect certain market assumptions. As a basis for considering such assumptions, GAAP establishes a three-tier value hierarchy, which prioritizes the inputs used to develop the assumptions and for measuring fair value as follows: (Level 1) observable inputs such as quoted prices in active markets for identical assets; (Level 2) inputs other than the quoted prices in active markets that are observable either directly or indirectly; and (Level 3) unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions. This hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. The Company measures the fair value of money market funds, U.S. Treasuries and government agency securities based on quoted prices in active markets for identical securities. Investments also include corporate debt securities which are valued either based on recent trades of securities in inactive markets or based on quoted market prices of similar instruments and other significant inputs derived from or corroborated by observable market data. The carrying amounts reflected in the condensed consolidated balance sheets for cash, prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values, due to their short-term nature.

License and Collaboration Rev_2

License and Collaboration Revenue (Tables)	6 Months Ended
	Jun. 30, 2021
Revenue from Contract with Customer [Abstract]
Contract with Customer, Asset and Liability	The following table presents changes in the Company’s contract liabilities related to the Gilead License Agreement during the six months ended June 30, 2021 (in thousands): January 1, 2021 Additions Reductions June 30, 2021 Contract liabilities: Deferred revenue — related party 1,931 — (1,931) — Total $ 1,931 $ — $ (1,931) $ —

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value	Assets measured at fair value on a recurring basis as of June 30, 2021 were as follows (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Money market funds, included in cash equivalents $ 140,814 $ 140,814 $ — $ — Investments: Corporate debt securities 95,165 — 95,165 — U.S. Treasuries 7,486 7,486 — — Government agency securities 2,683 — 2,683 — Totals $ 246,148 $ 148,300 $ 97,848 $ — Assets measured at fair value on a recurring basis as of December 31, 2020 were as follows (in thousands): Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Money market funds, included in cash equivalents $ 147,492 $ 147,492 $ — $ — Investments: Corporate debt securities 63,691 — 63,691 — Government agency securities 2,005 — 2,005 — Totals $ 213,188 $ 147,492 $ 65,696 $ —

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-sale Securities by Security Type	Cash equivalents, short-term investments and long-term investments as of June 30, 2021 were comprised as follows (in thousands): June 30, 2021 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 140,814 $ — $ — $ 140,814 Corporate debt securities 79,316 6 (3) 79,319 Total cash equivalents and short-term investments $ 220,130 $ 6 $ (3) $ 220,133 Long-term investments: Corporate debt securities 15,868 — (22) 15,846 U.S. Treasuries 7,487 — (1) 7,486 Government agency securities 2,687 — (4) 2,683 Total long-term investments 26,042 — (27) 26,015 Total cash equivalents and investments $ 246,172 $ 6 $ (30) $ 246,148 Cash equivalents, short-term investments and long-term investments as of December 31, 2020 were comprised as follows (in thousands): December 31, 2020 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents and short-term investments: Money market funds, included in cash equivalents $ 147,492 $ — $ — $ 147,492 Corporate debt securities 56,985 9 (13) 56,981 Government agency securities 2,001 4 — 2,005 Total cash equivalents and short-term investments 206,478 13 (13) 206,478 Long-term investments: Corporate debt securities 6,727 — (17) 6,710 Total long-term investments 6,727 — (17) 6,710 Total cash equivalents and investments $ 213,205 $ 13 $ (30) $ 213,188

Restricted Cash (Tables)

Restricted Cash (Tables)	6 Months Ended
	Jun. 30, 2021
Cash and Cash Equivalents [Abstract]
Schedule of Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash that sums to the total of the same such amounts shown in the condensed consolidated statements of cash flows (in thousands): Six Months Ended Six Months Ended Beginning of Period End of Period Beginning of Period End of Period Cash and cash equivalents $ 147,493 $ 140,814 $ 53,241 $ 74,463 Restricted cash 1,270 1,270 1,270 1,270 Cash, cash equivalents and restricted cash $ 148,763 $ 142,084 $ 54,511 $ 75,733
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash that sums to the total of the same such amounts shown in the condensed consolidated statements of cash flows (in thousands): Six Months Ended Six Months Ended Beginning of Period End of Period Beginning of Period End of Period Cash and cash equivalents $ 147,493 $ 140,814 $ 53,241 $ 74,463 Restricted cash 1,270 1,270 1,270 1,270 Cash, cash equivalents and restricted cash $ 148,763 $ 142,084 $ 54,511 $ 75,733

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2021
Payables and Accruals [Abstract]
Schedule of Accrued Expenses	Accrued expenses as of June 30, 2021 and December 31, 2020 were comprised as follows (in thousands): June 30, December 31, 2021 2020 External research and development and professional services $ 4,973 $ 4,855 Employee compensation and benefits 4,453 6,825 Lab consumables and other 427 364 Total accrued expenses $ 9,853 $ 12,044

Common Stock and Preferred St_2

Common Stock and Preferred Stock (Tables)	6 Months Ended
	Jun. 30, 2021
Equity [Abstract]
Schedule of Stock by Class	As of June 30, 2021 and December 31, 2020, the Company had reserved for future issuance the following number of shares of common stock (in thousands): June 30, December 31, 2021 2020 Shares reserved for vesting of restricted stock units 802 588 Shares reserved for exercises of outstanding stock options 7,476 6,586 Shares reserved for future issuance under the 2017 Stock Option and Incentive Plan 1,486 1,284 Total shares reserved for future issuance 9,764 8,458

Stock-based Compensation (Table

Stock-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Share-based Payment Arrangement [Abstract]
Schedule of Stock-Based Compensation Expense	Total stock-based compensation expense recognized in the condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2021 and 2020 was as follows (in thousands): Three Months Ended Six Months Ended 2021 2020 2021 2020 Research and development $ 1,286 $ 1,196 $ 2,501 $ 2,377 General and administrative 1,649 1,447 3,259 2,884 Total stock-based compensation expense $ 2,935 $ 2,643 $ 5,760 $ 5,261
Schedule of Restricted Stock Activity	The Company has also granted RSUs to its employees under the 2017 Plan. The following table summarizes RSU activity for the six months ended June 30, 2021 (in thousands, except per share amounts): RSUs Weighted-Average Grant Date Fair Value per Share Unvested as of December 31, 2020 588 $ 5.82 Issued 472 $ 11.90 Vested (223) $ 5.64 Cancelled (35) $ 8.65 Unvested as of June 30, 2021 802 $ 9.33
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The fair value of stock options granted during the three and six months ended June 30, 2021 and 2020 was calculated on the date of grant using the following weighted-average assumptions: Three Months Ended Six Months Ended 2021 2020 2021 2020 Risk-free interest rate 1.1 % 0.4 % 0.8 % 1.3 % Expected dividend yield — % — % — % — % Expected term (in years) 5.9 5.6 6.0 6.0 Expected volatility 82.5 % 75.4 % 81.8 % 72.0 %
Schedule of Stock Options, Activity	The following table summarizes stock option activity during the six months ended June 30, 2021 (in thousands, except per share amounts): Options Weighted-Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at December 31, 2020 6,586 $ 8.30 6.5 $ 13,110 Granted 1,475 $ 11.03 Exercised (363) $ 3.04 Cancelled (222) $ 11.58 Outstanding at June 30, 2021 7,476 $ 9.00 6.8 $ 10,719 Exercisable at June 30, 2021 4,680 $ 8.75 5.6 $ 9,239

Net Loss per Share (Tables)

Net Loss per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Net Loss per Share	For purposes of the diluted net loss per share calculation, outstanding stock options and unvested RSUs are considered to be potentially dilutive securities, however the following weighted-average amounts were excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive (in thousands): Three Months Ended Six Months Ended 2021 2020 2021 2020 Outstanding stock options 7,332 6,670 7,143 6,504 Unvested RSUs 809 754 745 689 Total 8,141 7,424 7,888 7,193

Nature of Business (Details)

Nature of Business (Details) - USD ($) $ in Millions	Aug. 05, 2021	Jun. 30, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cash, cash equivalents, and marketable securities		$ 246.1
Subsequent Event
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Duration of funding requirement	12 months

License and Collaboration Rev_3

License and Collaboration Revenue - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Aug. 31, 2020	Jul. 31, 2021	Jun. 30, 2021	Oct. 31, 2020	Aug. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Oct. 16, 2020
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone revenue						$ 25,368	$ 0	$ 26,907	$ 0
Reimbursable expenses due from related party (less than for December 31, 2020)			$ 24,976			24,976		24,976		$ 31
Gilead Transaction Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Non-refundable upfront payment received				$ 85,000
Aggregate revenue for clinical and regulatory milestones	$ 510,000
Aggregate revenue for sales milestones	$ 175,000
Transaction price				$ 64,300
Milestone revenue						25,400		26,900
Reimbursable expenses due from related party (less than for December 31, 2020)			25,000			25,000		25,000		100
Gilead Transaction Agreements | Subsequent Event
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Proceeds from milestone achievement earned		$ 25,000
Gilead Transaction Agreements | Gilead Sciences, Inc.
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Non-refundable upfront payment received					$ 85,000
Gilead Transaction Agreements | Gilead Sciences, Inc. | Gilead Transaction Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Reimbursable expenses due from related party (less than for December 31, 2020)			25,000			25,000		25,000		$ 100
Gilead Transaction Agreements | JTX-1811 License
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Milestone achievement earned			$ 25,000
Transaction price											$ 60,800
Milestone revenue						25,000		25,000
Gilead Transaction Agreements | Research and Transition Services
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Transaction price											3,500
Milestone revenue						$ 400		$ 1,900
Gilead Stock Purchase Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Sale of stock, shares issued (in shares)				5,539,727
Proceeds from stock offering, net				$ 35,000
Aggregate fair value of shares issued on transaction				$ 55,700
Closing price per share (in USD per share)				$ 10.06
Sale of stock, price per share (USD per share)				$ 6.32
Consecutive trading days to determine weighted average share price				30 days
Sale amount over weighted average share price, percent				30.00%
Discount on shares issued transaction											$ 20,700
Gilead Stock Purchase Agreement | Gilead Sciences, Inc. | Gilead Transaction Agreements
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Sale of stock, shares issued (in shares)					5,539,727
Proceeds from stock offering, net					$ 35,000

License and Collaboration Rev_4

License and Collaboration Revenue - Schedule of Contract Liabilities (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Beginning balance	$ 1,931
Additions	0
Reductions	(1,931)
Ending balance	0
Gilead Sciences, Inc. | Gilead Transaction Agreements
Revenue from Contract with Customer [Abstract]
Beginning balance	1,931
Additions	0
Reductions	(1,931)
Ending balance	$ 0

Fair Value Measurements - Asset

Fair Value Measurements - Assets Measured at Fair Value (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Measurements, Recurring
Investments:
Totals	$ 246,148,000	$ 213,188,000
Liabilities measured at fair value	0	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Investments:
Totals	148,300,000	147,492,000
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Investments:
Totals	97,848,000	65,696,000
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Investments:
Totals	0	0
Corporate debt securities | Fair Value, Measurements, Recurring
Investments:
Available-for-sale debt securities, fair value	95,165,000	63,691,000
Corporate debt securities | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Investments:
Available-for-sale debt securities, fair value	0	0
Corporate debt securities | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Investments:
Available-for-sale debt securities, fair value	95,165,000	63,691,000
Corporate debt securities | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Investments:
Available-for-sale debt securities, fair value	0	0
U.S. Treasuries | Fair Value, Measurements, Recurring
Investments:
Available-for-sale debt securities, fair value	7,486,000
U.S. Treasuries | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Investments:
Available-for-sale debt securities, fair value	7,486,000
U.S. Treasuries | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Investments:
Available-for-sale debt securities, fair value	0
U.S. Treasuries | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Investments:
Available-for-sale debt securities, fair value	0
Government agency securities | Fair Value, Measurements, Recurring
Investments:
Available-for-sale debt securities, fair value	2,683,000	2,005,000
Government agency securities | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Investments:
Available-for-sale debt securities, fair value	0	0
Government agency securities | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Investments:
Available-for-sale debt securities, fair value	2,683,000	2,005,000
Government agency securities | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Investments:
Available-for-sale debt securities, fair value	0	0
Money market funds, included in cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	140,814,000	147,492,000
Money market funds, included in cash equivalents | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	140,814,000	147,492,000
Money market funds, included in cash equivalents | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	140,814,000	147,492,000
Money market funds, included in cash equivalents | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	0	0
Money market funds, included in cash equivalents | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds, included in cash equivalents	$ 0	$ 0

Investments - Available-for-sal

Investments - Available-for-sale Securities by Security Type (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Unrealized Gains	$ 6	$ 13
Unrealized Losses	(30)	(30)
Cash equivalents, short-term and long-term investments, carrying value	246,172	213,205
Cash equivalents, short-term and long-term investments, fair vale disclosure	246,148	213,188
Short-term Investments
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Unrealized Gains	6	13
Unrealized Losses	(3)	(13)
Total cash equivalents and short-term investments, carrying value	220,130	206,478
Total cash equivalents and short-term investments, fair value	220,133	206,478
Short-term Investments | Corporate debt securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Available-for-sale debt securities, amortized cost basis	79,316	56,985
Unrealized Gains	6	9
Unrealized Losses	(3)	(13)
Available-for-sale debt securities, fair value	79,319	56,981
Short-term Investments | Government agency securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Available-for-sale debt securities, amortized cost basis		2,001
Unrealized Gains		4
Unrealized Losses		0
Available-for-sale debt securities, fair value		2,005
Long-term Investments
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Available-for-sale debt securities, amortized cost basis	26,042	6,727
Unrealized Gains	0	0
Unrealized Losses	(27)	(17)
Available-for-sale debt securities, fair value	26,015	6,710
Long-term Investments | Corporate debt securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Available-for-sale debt securities, amortized cost basis	15,868	6,727
Unrealized Gains	0	0
Unrealized Losses	(22)	(17)
Available-for-sale debt securities, fair value	15,846	6,710
Long-term Investments | U.S. Treasuries
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Available-for-sale debt securities, amortized cost basis	7,487
Unrealized Gains	0
Unrealized Losses	(1)
Available-for-sale debt securities, fair value	7,486
Long-term Investments | Government agency securities
Debt Securities, Available-for-sale, Fair Value to Amortized Cost [Abstract]
Available-for-sale debt securities, amortized cost basis	2,687
Unrealized Gains	0
Unrealized Losses	(4)
Available-for-sale debt securities, fair value	2,683
Money market funds, included in cash equivalents
Debt Securities, Available-for-sale [Line Items]
Cash equivalents at carrying value	140,814	147,492
Cash equivalents at fair value	$ 140,814	$ 147,492

Investments - Narrative (Detail

Investments - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities in an unrealized loss position for less than twelve months	$ 39,800,000		$ 39,800,000		$ 28,300,000
Aggregate fair value of securities in an unrealized position for more than twelve months	0		0		$ 0
Realized gains or losses on available-for-sale securities	$ 0	$ 0	$ 0	$ 0

Restricted Cash - Narrative (De

Restricted Cash - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Cash and Cash Equivalents [Abstract]
Non-current restricted cash	$ 1.3	$ 1.3

Restricted Cash - Schedule of C

Restricted Cash - Schedule of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 140,814	$ 147,493	$ 74,463	$ 53,241
Restricted cash	1,270	1,270	1,270	1,270
Cash, cash equivalents and restricted cash	$ 142,084	$ 148,763	$ 75,733	$ 54,511

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
External research and development and professional services	$ 4,973	$ 4,855
Employee compensation and benefits	4,453	6,825
Lab consumables and other	427	364
Total accrued expenses	$ 9,853	$ 12,044

Common Stock and Preferred St_3

Common Stock and Preferred Stock - Narrative (Details) $ / shares in Units, $ in Millions	Dec. 17, 2019USD ($)	Mar. 31, 2021USD ($)$ / sharesshares	Jun. 30, 2021voteshares	Dec. 31, 2020shares
Subsidiary, Sale of Stock [Line Items]
Common stock shares authorized (in shares)			160,000,000	160,000,000
Common stock, votes per share | vote			1
Preferred stock shares authorized (in shares)			5,000,000	5,000,000
Preferred stock shares issued (in shares)			0	0
Preferred stock shares outstanding (in shares)			0	0
ATM Offering
Subsidiary, Sale of Stock [Line Items]
Aggregate offering price shares | $	$ 50
Sales commission percentage	3.00%
Sale of stock, shares issued (in shares)		3,156,200
Sale of stock, price per share (USD per share) | $ / shares		$ 9.87
Proceeds from stock offering, net | $		$ 30.2
Follow-on Public Offering
Subsidiary, Sale of Stock [Line Items]
Sale of stock, shares issued (in shares)		5,750,000
Sale of stock, price per share (USD per share) | $ / shares		$ 11.25
Proceeds from stock offering, net | $		$ 60.6

Common Stock and Preferred St_4

Common Stock and Preferred Stock - Shares Reserved for Future Issuance (Details) - shares	Jun. 30, 2021	Dec. 31, 2020	Jan. 31, 2017
Conversion of Stock [Line Items]
Common stock reserved for potential conversion (in shares)	9,764,000	8,458,000	1,753,758
Shares reserved for vesting of restricted stock units
Conversion of Stock [Line Items]
Common stock reserved for potential conversion (in shares)	802,000	588,000
Shares reserved for exercises of outstanding stock options
Conversion of Stock [Line Items]
Common stock reserved for potential conversion (in shares)	7,476,000	6,586,000
Shares reserved for future issuance under the 2017 Stock Option and Incentive Plan
Conversion of Stock [Line Items]
Common stock reserved for potential conversion (in shares)	1,486,000	1,284,000

Stock-based Compensation - Narr

Stock-based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 01, 2021	Jan. 01, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Jan. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock eligible to be purchased (in shares)			9,764,000		9,764,000		8,458,000	1,753,758
Options granted (in shares)					1,475,000
Weighted average fair value of options granted (in dollars per share)			$ 6.21	$ 4.15	$ 7.63	$ 4.22
Intrinsic value of stock options exercised (less than for all periods other than current period YTD)			$ 0.1	$ 0.1	$ 2.9	$ 0.1
Unrecognized stock-based compensation expense, options			$ 15.6		$ 15.6
Inducement Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)			225,000
Shares reserved for future issuance under the 2017 Stock Option and Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance (in shares)			1,485,743		1,485,743
Shares of common stock eligible to be purchased (in shares)			1,486,000		1,486,000		1,284,000
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock eligible to be purchased (in shares)			802,000		802,000		588,000
Vested (in shares)			0	0	223,000
Aggregate fair value of awards vested in period					$ 1.5	$ 0.8
Unrecognized stock-based compensation expense, RSUs			$ 6		$ 6
Remaining weighted average vesting period					2 years
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining weighted average vesting period					2 years 6 months
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance (in shares)								0
Shares of common stock eligible to be purchased (in shares)								243,758
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock eligible to be purchased (in shares)								1,510,000
Percent of outstanding shares able to be added each year								4.00%
Additional shares authorized (in shares)	1,669,162	1,349,526
2017 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock eligible to be purchased (in shares)								302,000
Percent of outstanding shares able to be added each year								1.00%
Additional shares authorized (in shares)	417,291	337,381
Shares of common stock to determine number of additional shares (in shares)								603,000

Stock-based Compensation - Stoc

Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,935	$ 2,643	$ 5,760	$ 5,261
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,286	1,196	2,501	2,377
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,649	$ 1,447	$ 3,259	$ 2,884

Stock-based Compensation - RSU

Stock-based Compensation - RSU Activity (Details) - RSUs - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021
RSUs
Beginning unvested balance (in shares)			588,000
Issued (in shares)			472,000
Vested (in shares)	0	0	(223,000)
Cancelled (in shares)			(35,000)
Ending unvested balance (in shares)	802,000		802,000
Weighted-Average Grant Date Fair Value per Share
Beginning unvested balance (in dollars per share)			$ 5.82
Issued (in dollars per share)			11.90
Vested (in dollars per share)			5.64
Cancelled (in dollars per share)			8.65
Ending unvested balance (in dollars per share)	$ 9.33		$ 9.33

Stock-based Compensation - Weig

Stock-based Compensation - Weighted Average Assumptions (Details) - Employee Stock Option	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.10%	0.40%	0.80%	1.30%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Expected term (in years)	5 years 10 months 24 days	5 years 7 months 6 days	6 years	6 years
Expected volatility	82.50%	75.40%	81.80%	72.00%

Stock-based Compensation - St_2

Stock-based Compensation - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares
Options
Beginning outstanding balance (in shares) | shares	6,586
Granted (in shares) | shares	1,475
Exercises of common stock options (in shares) | shares	(363)
Cancelled or forfeited (in shares) | shares	(222)
Ending outstanding balance (in shares) | shares	7,476	6,586
Exercisable (in shares) | shares	4,680
Weighted-Average Exercise Price
Beginning outstanding balance (in dollars per share) | $ / shares	$ 8.30
Granted (in dollars per share) | $ / shares	11.03
Exercised (in dollars per share) | $ / shares	3.04
Cancelled or forfeited (in dollars per share) | $ / shares	11.58
Ending outstanding balance (in dollars per share) | $ / shares	9	$ 8.30
Exercisable (in dollars per share) | $ / shares	$ 8.75
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Remaining contractual life, outstanding (in years)	6 years 9 months 18 days	6 years 6 months
Remaining contractual life, exercisable (in years)	5 years 7 months 6 days
Aggregate intrinsic value, outstanding | $	$ 10,719	$ 13,110
Aggregate intrinsic value, exercisable | $	$ 9,239

Related-party Transactions (Det

Related-party Transactions (Details) - USD ($) $ in Thousands	1 Months Ended
	Oct. 31, 2020	Aug. 31, 2020	Jun. 30, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Reimbursable expenses due from related party (less than for December 31, 2020)			$ 24,976	$ 31
Gilead Transaction Agreements
Related Party Transaction [Line Items]
Non-refundable upfront payment received	$ 85,000
Reimbursable expenses due from related party (less than for December 31, 2020)			25,000	100
Gilead Stock Purchase Agreement
Related Party Transaction [Line Items]
Proceeds from stock offering, net	$ 35,000
Sale of stock, shares issued (in shares)	5,539,727
Gilead Sciences, Inc. | Gilead Transaction Agreements
Related Party Transaction [Line Items]
Non-refundable upfront payment received		$ 85,000
Gilead Sciences, Inc. | Gilead Transaction Agreements | Gilead Transaction Agreements
Related Party Transaction [Line Items]
Reimbursable expenses due from related party (less than for December 31, 2020)			$ 25,000	$ 100
Gilead Sciences, Inc. | Gilead Stock Purchase Agreement | Gilead Transaction Agreements
Related Party Transaction [Line Items]
Proceeds from stock offering, net		$ 35,000
Sale of stock, shares issued (in shares)		5,539,727

Net Loss per Share - Schedule o

Net Loss per Share - Schedule of Antidilutive Securities Excluded from Computation of Net Loss per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of net loss per share (in shares)	8,141	7,424	7,888	7,193
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of net loss per share (in shares)	7,332	6,670	7,143	6,504
RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of net loss per share (in shares)	809	754	745	689