Stockholders' equity - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 31, 2022
Class of Stock [Line Items]
Accumulated deficit subject to restriction	$ 10.5
Accumulated profits (at least)	10.00%
Employee stock options
Class of Stock [Line Items]
Common stock reserved for future issuance (in shares)		6,256,346