Summary of Significant Accounting Policies - Contract Balances from Contracts with Customers - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Feb. 28, 2023	Dec. 31, 2022	Feb. 28, 2022	Dec. 31, 2021
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with customer liability	$ 44,606	$ 59,247	$ 44,606	$ 59,247		$ 50,211		$ 92,068
Revenue from contract with customer	83,153	14,162	133,022	52,240
Revenue recognized, previously deferred	2,893	10,864	5,605	36,624
Current portion of deferred revenue	14,389		14,389			$ 13,856
License and milestone fees
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer	40	$ 6,973	15,071	$ 37,865
Future Technological Improvements
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer			100
Revenue recognized, previously deferred			200
Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd | License and milestone fees
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue recognized, previously deferred			28,500
Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd | Upfront payment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
License agreement upfront payment receivable	45,000		45,000
Lilly
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
License agreement upfront payment receivable							$ 13,000
Lilly | License and milestone fees
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer			9,200
Lilly | Upfront payment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
License agreement upfront payment receivable	$ 13,000		13,000
KADCYLA | Royalty revenue
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net proceeds from sale of residual rights to receive royalty payments			5,500
Revenue recognized, previously deferred			8,000
Vertex | License and milestone fees
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customer			15,000
Vertex | Upfront payment
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
License agreement upfront payment receivable					$ 15,000
Revenue from contract with customer			$ 15,000