Significant agreements - Summary of Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Contract liabilities:
Beginning Balance	$ 71,340	$ 35,156
Additions	10,000	49,056
Deductions	(8,238)	(11,697)
Impact of Exchange Rates	(6,723)	(1,175)
Ending Balance	66,379	71,340
Ionis
Contract liabilities:
Beginning Balance	34,115
Additions	0
Deductions	(4,569)
Impact of Exchange Rates	(3,159)
Ending Balance	26,387	34,115
Genentech
Contract liabilities:
Beginning Balance	34,436	27,579
Additions	10,000	13,000
Deductions	(2,346)	(5,660)
Impact of Exchange Rates	(3,412)	(483)
Ending Balance	38,678	34,436
Dementia Discovery Fund
Contract liabilities:
Beginning Balance	428	821
Additions	0	0
Deductions	(158)	(391)
Impact of Exchange Rates	(35)	(2)
Ending Balance	235	428
AstraZeneca
Contract liabilities:
Beginning Balance	2,361	3,756
Additions	0	54
Deductions	(1,165)	(1,404)
Impact of Exchange Rates	(117)	(45)
Ending Balance	1,079	2,361
Ionis Evaluation and Option Agreement
Contract liabilities:
Beginning Balance	$ 34,115	3,000
Additions		36,002
Deductions		(4,242)
Impact of Exchange Rates		(645)
Ending Balance		$ 34,115