Collaboration and license agreements - Roche Agreement (Details) $ in Millions		1 Months Ended			12 Months Ended
	May 29, 2023	Mar. 31, 2025 USD ($)	Nov. 30, 2020 USD ($) target	Dec. 31, 2018 USD ($) target performanceObligation	Dec. 31, 2025 target
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Number of performance obligations | performanceObligation				12
Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice period for termination of agreement	90 days
Restated Roche Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional upfront consideration received				$ 40.0
Number of potential targets | target			5	6
Number of targets | target			2		2
Annual research plan payments receivables			$ 1.0
Regulatory milestone achieved		$ 2.0
Collaborative Arrangement, Addition To The Transaction Price		$ 4.0
Option exercise fees			8.0
Restated Roche Agreement | Maximum | Research, development and commercial milestone payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive			273.0
Restated Roche Agreement | Maximum | One-time sales-based payments
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Amount eligible to receive			150.0
Restated Roche Agreement | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Written notice period for termination of agreement					90 days
Restated Roche Agreement | Lead series identification achievement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront fees			$ 2.0