Significant agreements - Bayer Collaboration Agreement (Details) $ in Thousands, £ in Millions		3 Months Ended		9 Months Ended
	May 04, 2023 USD ($) item	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	May 04, 2023 GBP (£) item	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Significant agreements.
Revenue from collaborative arrangement		$ 5,352	$ 3,040	$ 21,645	$ 11,278
Deferred revenue		134,772		134,772			$ 61,873	$ 71,340
Bayer Collaboration Agreement
Significant agreements.
Number of collaboration targets | item	2					2
Upfront cash payment	$ 45,000
Milestone payments, receivable | £						£ 583.5
Period to terminate agreement upon written notice for uncured material breach	90 days
Number of business days to terminate agreement upon non payment by Bayer	20 days
Transaction price	$ 47,500
Estimated amount payable to CROs	$ 2,500
Expected period for satisfaction of performance obligations	4 years
Material rights exercise period	7 years
Revenue from collaborative arrangement		434	$ 0	434	$ 0
Deferred revenue		$ 42,521		$ 42,521			$ 0
Bayer Collaboration Agreement | Minimum
Significant agreements.
Number of candidate compounds into further development | item	1					1
Threshold period to terminate agreement upon written notice by Bayer	60 days
Bayer Collaboration Agreement | Maximum
Significant agreements.
Number of collaboration targets | item	3					3
Milestone payments receivable | £						£ 194.5
Threshold period to terminate agreement upon written notice by Bayer	90 days
Bayer Collaboration Agreement | Development and regulatory milestones | Maximum
Significant agreements.
Milestone payments receivable | £						178.3
Bayer Collaboration Agreement | Across all three potential target programs
Significant agreements.
Milestone payments receivable | £						£ 534.9