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Collaboration and License Agreements - Amgen, Inc - Additional Information (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		12 Months Ended
	Sep. 29, 2017 USD ($) Target	Oct. 31, 2017 USD ($) $ / shares shares	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, value of shares issued in connection with agreement					$ 0	$ 107,712
Deferred revenue					301,326	284,760	$ 318,707
Amgen Inc | EGFR Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue					18,000
Amgen Inc | Amgen Other Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue					600
Collaboration and License Agreement | Amgen Inc
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received	$ 40,000	$ 40,000
Common stock, shares issuable under agreement | shares		1,156,069
Common stock, shares issuable under agreement, price per share | $ / shares		$ 17.30
Common stock, value of shares issued in connection with agreement		$ 20,000
Number of targets selected | Target	1
Number of additional collaboration target | Target	2
Total transaction price	$ 51,200
Portion of transaction price allocated to premium on sale of common stock	500
Estimated fair value of products	10,700
Collaboration and License Agreement | Amgen Inc | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contingent payments payable	203,000
Collaboration and License Agreement | Amgen Inc | EGFR Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total transaction price	46,400
Estimated research service period			7 years	8 years
Deferred revenue					18,000	21,800
Collaboration and License Agreement | Amgen Inc | EGFR Products | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contingent milestone payments receivable	$ 460,000
Percentage share of profit and losses	50.00%
Collaboration and License Agreement | Amgen Inc | Amgen Products | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contingent milestone payments receivable	$ 950,000
Number of targets | Target	3
Collaboration and License Agreement | Amgen Inc | Amgen Other Products
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Total transaction price	$ 4,800
Estimated research service period	6 years
Revenue recognition upon performance obligation	$ 4,800
Deferred revenue					$ 600	$ 1,800
Sublicense Agreement | Amgen Inc | Maximum | UC Regents
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Sublicense payment percentage	7.50%

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