Significant agreements - Summary of Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019
Contract assets
Beginning Balance	$ 0	$ 0
Additions		149
Deductions		(149)
Impact of Exchange Rates		0
Ending Balance		0
Contract liabilities:
Beginning Balance	5,657	14,635
Additions	31,433	1,172
Deductions	(3,496)	(10,413)
Impact of Exchange Rates	(319)	263
Ending Balance	33,275	5,657
AstraZeneca
Contract liabilities:
Beginning Balance	4,913	4,727
Additions	433	58
Deductions	(118)	(35)
Impact of Exchange Rates	(138)	163
Ending Balance	5,090	4,913
Sanofi
Contract liabilities:
Beginning Balance	0	9,908
Additions		0
Deductions		(9,984)
Impact of Exchange Rates		76
Ending Balance	0	0
Dementia Discovery Fund
Contract assets
Beginning Balance	744	0
Additions		1,114
Deductions		(394)
Impact of Exchange Rates		24
Ending Balance		744
Contract liabilities:
Beginning Balance	744
Deductions	(178)
Impact of Exchange Rates	(16)
Ending Balance	550	$ 744
Genetech
Contract liabilities:
Additions	31,000
Deductions	(3,200)
Impact of Exchange Rates	(165)
Ending Balance	$ 27,635

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Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in measure of progress which increases (decreases) right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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Amount of increase from purchase of right to consideration in exchange for good or service transferred to customer when right is conditioned on passage of time.

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Amount of decrease from sale of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time and other income.

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