Collaboration arrangements and concentration of credit risk - CSL Behring and Bristol-Myers Squibb collaboration - Narrative (Details) $ in Thousands			1 Months Ended	3 Months Ended
	Dec. 01, 2021 item	Dec. 01, 2020 USD ($) item	Apr. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Collaboration arrangements
Number of collaboration targets | item		4
Revenue				$ 1,792	$ 454
CSL Behring collaboration
Collaboration arrangements
Accounts receivable				38,300		$ 2,900
Contract asset				55,000		$ 55,000
Milestone payments collected				20,000
Uncollected submission milestone payment				35,000
CSL Behring collaboration | Subsequent events.
Collaboration arrangements
Uncollected submission milestone payment received			$ 35,000
Collaborative Revenue Including Revenue From Related Party
Collaboration arrangements
Revenue				400	500
Collaborative revenue | CSL Behring collaboration
Collaboration arrangements
Revenue				1,400	0
Collaborative revenue | Bristol Myers Squibb
Collaboration arrangements
Collaboration Agreement, Threshold Number Of Collaboration Targets That Can Be Replaced | item	2
Collaboration Agreement, Threshold Research, Development And Regulatory Milestone Payments Receivable		$ 217,000
Collaborative revenue | Bristol Myers Squibb | Minimum
Collaboration arrangements
Number of collaboration targets | item		4
Collaborative revenue | Bristol Myers Squibb | Maximum
Collaboration arrangements
Number of collaboration targets | item		10
License revenue | CSL Behring collaboration
Collaboration arrangements
Revenue				$ 0	$ 0