Stock-based compensation - Schedule of Stock Options Outstanding and Exercisable (Details)	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options outstanding (in shares) | shares	23,253,963
Options exercisable (in shares) | shares	9,954,974
Exercise Price at $0.18
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price, lower range limit (in dollars per share)	$ 0.18
Exercise price, upper range limit (in dollars per share)	$ 0.18
Options outstanding (in shares) | shares	5,037,657
Options outstanding, weighted average remaining contractual life (years)	8 years 3 months 18 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 0.18
Options exercisable (in shares) | shares	3,256,438
Options exercisable, weighted average exercise price (in dollars per share)	$ 0.18
Exercise Price at $0.21
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price, lower range limit (in dollars per share)	0.21
Exercise price, upper range limit (in dollars per share)	$ 0.21
Options outstanding (in shares) | shares	9,300,668
Options outstanding, weighted average remaining contractual life (years)	8 years 6 months
Options outstanding, weighted average exercise price (in dollars per share)	$ 0.21
Options exercisable (in shares) | shares	3,454,922
Options exercisable, weighted average exercise price (in dollars per share)	$ 0.21
Exercise Price at $1.42
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price, lower range limit (in dollars per share)	1.42
Exercise price, upper range limit (in dollars per share)	$ 1.42
Options outstanding (in shares) | shares	7,524,114
Options outstanding, weighted average remaining contractual life (years)	8 years 6 months
Options outstanding, weighted average exercise price (in dollars per share)	$ 1.42
Options exercisable (in shares) | shares	2,664,790
Options exercisable, weighted average exercise price (in dollars per share)	$ 1.42
Exercise Price at $1.49
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price, lower range limit (in dollars per share)	1.49
Exercise price, upper range limit (in dollars per share)	$ 1.49
Options outstanding (in shares) | shares	40,581
Options outstanding, weighted average remaining contractual life (years)	5 years 9 months 18 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 1.49
Options exercisable (in shares) | shares	40,418
Options exercisable, weighted average exercise price (in dollars per share)	$ 1.49
Exercise Price at $5.24
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price, lower range limit (in dollars per share)	5.24
Exercise price, upper range limit (in dollars per share)	$ 5.24
Options outstanding (in shares) | shares	705,146
Options outstanding, weighted average remaining contractual life (years)	4 years
Options outstanding, weighted average exercise price (in dollars per share)	$ 5.24
Options exercisable (in shares) | shares	538,406
Options exercisable, weighted average exercise price (in dollars per share)	$ 5.24
Exercise Price at $10.26
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price, lower range limit (in dollars per share)	10.26
Exercise price, upper range limit (in dollars per share)	$ 10.26
Options outstanding (in shares) | shares	645,797
Options outstanding, weighted average remaining contractual life (years)	9 years 1 month 6 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 10.26
Options exercisable (in shares) | shares	0
Options exercisable, weighted average exercise price (in dollars per share)	$ 0