Significant agreements - Dementia Discovery Fund Agreement (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
Significant agreements.
Collaboration revenues		$ 26,976	$ 14,463	$ 11,697
Deferred revenue		135,194	61,873	71,340
Dementia Discovery Fund
Significant agreements.
Upfront cash payment					$ 1,100
Collaboration revenues		0	386	391
Deferred revenue		$ 0	$ 0	$ 428
Dementia Discovery Fund | Specific scientific criteria milestone
Significant agreements.
Milestone payment received	$ 500