Net loss per share attributable to common stockholders - Antidilutive shares (Details) - shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Amounts excluded from computation of diluted net loss per share	7,156,285	5,116,129
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Amounts excluded from computation of diluted net loss per share	6,696,436	4,957,855
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Amounts excluded from computation of diluted net loss per share	301,575
Warrant to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Amounts excluded from computation of diluted net loss per share	158,274	158,274