Stockholders' equity - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018
Options Outstanding
Outstanding, beginning balance (in shares)	20,342,259
Outstanding, ending balance (in shares)	19,703,879		20,342,259
2021 Stock incentive Plan
Options Outstanding
Outstanding, beginning balance (in shares)	19,942,259
Granted (in shares)	0
Exercised (in shares)	(376,578)
Canceled (in shares)	(261,802)
Outstanding, ending balance (in shares)	19,303,879		19,942,259
Weighted Average Exercise Price
Outstanding, beginning balance (in USD per share)	$ 9.70
Granted (in USD per share)	0
Exercised (in USD per share)	4.03
Canceled (in USD per share)	15.06
Outstanding, ending balance (in USD per share)	$ 9.74		$ 9.70
Outstanding, Weighted Average Remaining Contractual Term (in years)	7 years 10 months 17 days		8 years 1 month 20 days
Outstanding, Aggregate Intrinsic Value	$ 102,880		$ 226,350
Vested and Expected to Vest, Awards Outstanding (in shares)	19,303,879
Vested and Expected to Vest, Weighted Average Exercise Price (in USD per shares)	$ 9.74
Vested and Expected to Vest, Weighted Average Remaining Contractual Term (in years)	7 years 10 months 17 days
Vested and Expected to Vest, Aggregate Intrinsic Value	$ 102,880
Exercisable, Awards Outstanding (in shares)	9,129,677
Exercisable, Weighted Average Exercise Price (in USD per share)	$ 5.30
Exercisable, Weighted Average Remaining Contractual Term (in years)	7 years 3 months
Exercisable, Aggregate Intrinsic Value	$ 67,191
Performance-Based Awards
Options Outstanding
Granted (in shares)				350,000	50,000
Performance-Based Awards | Amended and Restated 2010 Equity Incentive Plan
Options Outstanding
Outstanding, beginning balance (in shares)	400,000
Granted (in shares)	0
Exercised (in shares)	0
Canceled (in shares)	0
Outstanding, ending balance (in shares)	400,000		400,000
Weighted Average Exercise Price
Outstanding, beginning balance (in USD per share)	$ 10.12
Granted (in USD per share)
Exercised (in USD per share)
Canceled (in USD per share)
Outstanding, ending balance (in USD per share)	$ 10.12		$ 10.12
Outstanding, Weighted Average Remaining Contractual Term (in years)	8 years 4 months 9 days	8 years 7 months 6 days
Outstanding, Aggregate Intrinsic Value	$ 936		$ 3,768
Vested and Expected to Vest, Awards Outstanding (in shares)	400,000
Vested and Expected to Vest, Weighted Average Exercise Price (in USD per shares)	$ 10.12
Vested and Expected to Vest, Weighted Average Remaining Contractual Term (in years)	8 years 4 months 9 days
Vested and Expected to Vest, Aggregate Intrinsic Value	$ 936
Exercisable, Awards Outstanding (in shares)	179,166
Exercisable, Weighted Average Exercise Price (in USD per share)	$ 10.94
Exercisable, Weighted Average Remaining Contractual Term (in years)	8 years 7 months 2 days
Exercisable, Aggregate Intrinsic Value	$ 272