Stockholders' equity - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Number of Shares
Options outstanding at beginning of period (in shares)	6,846,289
Options granted (in shares)	3,346,049
Options exercised (in shares)	(124,928)
Options cancelled/forfeited (in shares)	(1,103,465)
Options outstanding at end of period (in shares)	8,963,945	6,846,289
Options exercisable, Number of options (in shares)	3,665,224
Weighted Average Exercise Price
Options outstanding at beginning of period (in dollars per share)	$ 6.42
Options granted (in dollars per share)	8.70
Options exercised (in dollars per share)	3.28
Options cancelled/forfeited (in dollars per share)	7.31
Options outstanding at end of period (in dollars per share)	7.20	$ 6.42
Options exercisable, Weighted average exercise price (in dollars per share)	$ 5.99
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, Weighted average remaining contractual life (in years)	8 years 3 months 25 days	8 years 8 months 15 days
Options exercisable, Weighted average remaining contractual life (in years)	7 years 5 months 12 days
Options outstanding at beginning of period, Aggregate intrinsic value (in dollars)	$ 53,127
Options outstanding at end of period, Aggregate intrinsic value (in dollars)	6,912	$ 53,127
Options exercisable, Aggregate intrinsic value (in dollars)	$ 4,729