Significant agreements - Collaboration revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Significant agreements.
Collaboration revenues	$ 26,976	$ 14,463	$ 11,697
Bayer
Significant agreements.
Collaboration revenues	1,160	0	0
Novartis
Significant agreements.
Collaboration revenues	1,909
Ionis
Significant agreements.
Collaboration revenues	10,734	9,347	4,242
Genentech
Significant agreements.
Collaboration revenues	11,969	3,565	5,660
Dementia Discovery Fund
Significant agreements.
Collaboration revenues	0	386	391
AstraZeneca
Significant agreements.
Collaboration revenues	$ 1,204	$ 1,165	$ 1,404