Significant agreements - Evaluation and Option Agreement (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaboration revenues	$ 1,808	$ 1,129
Deferred revenue	$ 35,710		$ 35,156	$ 5,657
Evaluation and Option Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Term, Bicycle Research Team (in months)	4 months
Threshold period for receipt of revenue after receipt of the materials and related data package	5 days
Term extension (in years)	2 months
Extension fees receivable	$ 2,000		2,000
Threshold period of notice required for termination of agreement	30 days
Upfront cash payment	$ 3,000
Collaboration revenues	0		3,000
Deferred revenue	3,027		$ 3,000
Transaction price	$ 3,000