Stock-based compensation - Stock Options - (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning balance (in shares) | shares	5,013,193
Granted (in shares) | shares	3,681,075
Exercised (in shares) | shares	(89,012)
Cancelled or forfeited (in shares) | shares	(2,405,685)
Outstanding, ending balance (in shares) | shares	6,199,571
Exercisable (in shares) | shares	2,744,489
Weighted Average Exercise Price
Outstanding (in dollars per share)	$ 12.69
Granted (in dollars per share)	5.17
Exercised (in dollars per share)	7.07
Cancelled or forfeited (in dollars per share)	13.15
Outstanding (in dollars per share)	8.12
Exercisable (in dollars per share)	$ 10.56
Remaining Contractual Life
Outstanding	7 years 10 months 24 days
Exercisable	6 years 6 months
Aggregate Intrinsic Value
Outstanding | $	$ 6,095
Exercisable | $	$ 2,287
Stock options
Options disclosures
Weighted average fair value of grants (in dollars per share)	$ 3.60
Unrecognized stock-based compensation expense | $	$ 12,800
Remaining weighted-average remaining vesting period	2 years 10 months 24 days