Significant agreements - Ionis Evaluation and Option Agreement (Details) - USD ($) $ in Thousands			1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 27, 2023	Jul. 09, 2021	Jan. 31, 2021	Mar. 31, 2023	Dec. 31, 2020	Dec. 31, 2022	Dec. 31, 2021
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue				$ 108,721		$ 61,873	$ 71,340
Ionis Evaluation and Option Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Term of the Evaluation Period (in months)					4 months
Upfront cash payment		$ 3,000	$ 3,000	$ 3,000	$ 3,000
Threshold period of notice required for termination of agreement				30 days
Deferred revenue					$ 3,000	21,500
Novartis Collaboration Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront cash payment	$ 50,000
Deferred revenue				$ 50,467		$ 0