Collaboration and license agreements - Narrative (Details) $ in Thousands	1 Months Ended						3 Months Ended		40 Months Ended
	Sep. 30, 2021 USD ($)	Aug. 31, 2021	Nov. 30, 2020 USD ($) target	Feb. 29, 2020 USD ($) protein	Dec. 31, 2018 USD ($) target	Mar. 31, 2017 USD ($) target_protein	Mar. 31, 2023 USD ($) target performanceObligation	Mar. 31, 2022 USD ($)	Jun. 30, 2020 USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized that was included in the contract liability at the beginning of the period							$ 3,231	$ 6,267
Transaction price allocated to performance obligation							$ 67,822
Restated Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional upfront consideration received					$ 40,000
Number of potential targets | target			5		6
Number of targets | target							3
Annual research plan payments receivables			$ 1,000
Annual research plan payments periods			3 years
Restated Roche Agreement | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Option exercise fees			$ 7,000
Written notice period for termination of agreement							90 days
Restated Roche Agreement | Minimum | Research, development and commercial milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive			260,000
Restated Roche Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Option exercise fees			12,000
Option exercise fees, through Phase 1 trials			20,000
Restated Roche Agreement | Maximum | Research, development and commercial milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive			275,000
Restated Roche Agreement | Maximum | One-time sales-based payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive			150,000
Restated Roche Agreement | Lead Series Identification Achievement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront fees			2,000
Restated Roche Agreement | Good Laboratory Practice (“GLP”) Toxicology (“Tox”) Study Phase
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront fees			$ 3,000
Biogen License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of targets | performanceObligation							5
Research agreement, period				54 months
Nonrefundable upfront payment				$ 45,000
Number of performance obligation | performanceObligation							1
Number of additional targets | target							2
Biogen License Agreement | Research and development services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized that was included in the contract liability at the beginning of the period							$ 55,000
Transaction price allocated to performance obligation							$ 9,100
Biogen License Agreement | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice period for termination of agreement				90 days
Biogen License Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of targeted protein degradation | protein				5
Biogen License Agreement | Maximum | Research and development milestones
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received				$ 35,000
Biogen License Agreement | Maximum | One-time sales-based payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received				$ 26,000
Calico License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of targets | target							5
Number of performance obligation | performanceObligation							1
Research term						5 years
Amount payable for extend research term option	$ 1,000
Research extend term		1 year
Upfront payment									$ 5,000
Annual payments									$ 5,000
Initial contractual term on straight line basis							5 years
Additional transaction price allocated to performance obligation	$ 1,000
Contractual term	6 years
Calico License Agreement | Research and development services
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized that was included in the contract liability at the beginning of the period							$ 13,000
Calico License Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of target proteins | target_protein						5
Calico License Agreement | Maximum | One-time sales-based payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received						$ 65,000
Calico License Agreement | Maximum | Potential research, development and commercial milestone payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payment received						$ 132,000
Restated Roche Agreement And Biogen License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Transaction price allocated to performance obligation							$ 36,800