Net loss per share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net loss	$ (35,542)	$ (27,403)	$ (26,029)	$ (24,330)	$ (28,933)	$ (15,090)	$ (88,974)	$ (68,353)	$ (100,777)	$ (79,207)
Denominator:
Weighted average common shares outstanding, basic	38,663,469			34,862,116			36,364,284	34,807,439
Weighted average common shares outstanding, diluted	38,663,469			34,862,116			36,364,284	34,807,439
Net loss per share, basic	$ (0.92)			$ (0.70)			$ (2.45)	$ (1.96)
Net loss per share, diluted	$ (0.92)			$ (0.70)			$ (2.45)	$ (1.96)
Number of weighted average restricted common stock	0			42			0	10,865