Net loss per share - Basic and Diluted Net Loss per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net loss	$ (13,090)	$ (14,930)	$ (11,831)	$ (22,101)	$ (28,020)	$ (33,932)
Accretion of redeemable convertible preferred stock to redemption value			(1,184)			(1,971)
Cumulative redeemable convertible preferred stock dividends			(885)			(2,296)
Net loss attributable to common stockholders - basic	(13,090)		(13,900)		(28,020)	(38,199)
Net loss attributable to common stockholders - diluted	$ (13,090)		$ (13,900)		$ (28,020)	$ (38,199)
Denominator:
Weighted average common shares outstanding - basic	42,494,055		694,698		42,346,607	668,180
Weighted average common shares outstanding - diluted	42,494,055		694,698		42,346,607	668,180
Net loss per share attributable to common stockholders - basic	$ (0.31)		$ (20.01)		$ (0.66)	$ (57.17)
Net loss per share attributable to common stockholders - diluted	$ (0.31)		$ (20.01)		$ (0.66)	$ (57.17)
Common Class A
Denominator:
Weighted average common shares outstanding - basic	36,940,676		694,698		36,443,792	668,180
Weighted average common shares outstanding - diluted	36,940,676		694,698		36,443,792	668,180
Net loss per share attributable to common stockholders - basic	$ (0.31)		$ (20.01)		$ (0.66)	$ (57.17)
Net loss per share attributable to common stockholders - diluted	$ (0.31)		$ (20.01)		$ (0.66)	$ (57.17)
Common Class B
Denominator:
Weighted average common shares outstanding - basic	5,553,379				5,902,815
Weighted average common shares outstanding - diluted	5,553,379				5,902,815
Net loss per share attributable to common stockholders - basic	$ (0.31)				$ (0.66)
Net loss per share attributable to common stockholders - diluted	$ (0.31)				$ (0.66)