License and Collaboration Agreements - Summary of Research and Development Costs Related to Collaboration and License Agreements (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development costs		$ 12,680	$ 9,913	$ 36,873	$ 26,582	[1]
Collaboration and License Agreements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development costs		46	1,443	3,117	2,341
Collaboration and License Agreements | Cullinan Oncology - Adimab
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development costs		$ 46		46	318
Collaboration and License Agreements | Amber - MIT
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development costs				71	276
Collaboration and License Agreements | Apollo - Wistar
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development costs					304
Collaboration and License Agreements | Florentine - Tubingen
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development costs			912		912
Collaboration and License Agreements | Pearl - Taiho
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development costs	$ 3,000		$ 531	$ 3,000	$ 531

[1] The shares and per share amounts for the nine months ended September 30, 2020 were derived from the unaudited consolidated financial statements as of that date and were retroactively adjusted as a result of the Reorganization and Reverse Stock Split. See Note 3 to the unaudited consolidated financial statements for additional details.