Collaboration agreements - GlaxoSmithKline (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Aug. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Collaboration agreements
Collaboration revenue		$ 10,654	$ 4,284	$ 18,456	$ 6,320
Deferred revenue		134,697	$ 37,914	134,697	$ 37,914	$ 147,653	$ 3,944
GSK Agreement
Collaboration agreements
Upfront payment received	$ 100,000
Collaboration arrangement, potential option exercise receivable	$ 90,000
Collaboration revenue		600		1,300
Deferred revenue		$ 96,700		$ 96,700		$ 98,000