Collaboration and License Agreements - Janssen Collaboration and Option Agreement (Details) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 07, 2020	Apr. 02, 2020	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021	Jun. 30, 2020	Dec. 31, 2021
Collaboration agreement
Collaboration contract asset				$ 8,777,000			$ 9,870,000
Revenue recognized				18,414,000	$ 11,142,000
Janssen Biotech Inc
Collaboration agreement
Upfront, non-refundable and non-creditable payment		$ 50,000,000.0		50,000,000.0
Transaction price of the agreement		66,000,000.0
Equity premium		16,000,000.0
Non-refundable upfront payments recorded as deferred revenue		$ 66,000,000.0
Milestone receivable				3,000,000.0
Milestone receivable with increase in initial transaction price				3,000,000.0
Milestone receivable to deferred revenue				3,000,000.0
Collaboration contract asset				14,000,000.0
Amortization of sublicense consideration				1,100,000	400,000
Revenue recognized				15,900,000	8,600,000
Deferred revenue				45,100,000
Deferred revenue classified as current				22,600,000
Research and development fees cash payments received				39,900
Janssen Biotech Inc | Research And Development
Collaboration agreement
Revenue recognized				9,800,000	6,800,000
Janssen Biotech Inc | Upfront Fee and Equity Premium
Collaboration agreement
Revenue recognized				6,100,000	$ 1,800,000
Janssen Biotech Inc | Sublicense Consideration
Collaboration agreement
Collaboration contract asset				$ 8,800,000
Johnson Johnson Innovation J J D C Inc | Stock Purchase Agreement
Collaboration agreement
Issuance of common stock in conjunction with public offering (in shares)				1,600,000
Common stock per share				$ 31.00
Aggregate purchase price of common stock				$ 50,000,000.0
Equity premium per share				$ 9.93
Aggregate equity premium on shares				$ 16,000,000.0
Proceeds from public offering of common stock, net of issuance costs				$ 34,000,000.0
Johnson Johnson Innovation J J D C Inc | Stock Purchase Agreement | Private Placement
Collaboration agreement
Issuance of common stock in conjunction with public offering (in shares)				50,000,000.0
Proceeds from public offering of common stock, net of issuance costs			$ 50,000,000.0
Share issue price (in dollars per share)			$ 28.31			$ 28.31
Issuance of common stock during period for private placements (in shares)						1,800,000
First Janssen Cancer Target | Maximum | Janssen Agreement
Collaboration agreement
Development, regulatory, and sales milestones	$ 898,000,000.0
Additional candidate milestone Payments	460,000,000.0
Additional Cancer Targets | Maximum | Janssen Agreement
Collaboration agreement
Development, regulatory, and sales milestones	706,000,000.0
Additional candidate milestone Payments	$ 340,000,000.0