Stock-based compensation - Stock Options - (Details) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022 USD ($) $ / shares shares	Dec. 31, 2021 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	2,965,075
Exercised (in shares) | shares	(74,496)
Cancelled or forfeited (in shares) | shares	(1,274,172)
Outstanding, ending balance (in shares) | shares	6,629,600	5,013,193
Exercisable (in shares) | shares	3,378,945
Weighted Average Exercise Price
Outstanding (in dollars per share) | $ / shares	$ 12.69
Granted (in dollars per share) | $ / shares	4.95
Exercised (in dollars per share) | $ / shares	7.90
Cancelled or forfeited (in dollars per share) | $ / shares	12.42
Outstanding (in dollars per share) | $ / shares	9.33	$ 12.69
Exercisable (in dollars per share) | $ / shares	$ 12.29
Remaining Contractual Life
Outstanding	7 years 2 months 12 days	5 years 7 months 6 days
Exercisable	5 years 3 months 18 days
Aggregate Intrinsic Value
Outstanding | $	$ 5,914	$ 1,165
Exercisable | $	1,575
Stock options
Options disclosures
Unrecognized stock-based compensation expense | $	$ 13,000
Remaining weighted-average remaining vesting period	3 years 1 month 6 days