Net loss per share - Antidilutive securities (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive securities (in shares)	20,575,973	19,806,096	8,527,597
Stock options outstanding
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive securities (in shares)	4,488,742	5,330,930	7,234,490
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive securities (in shares)	8,417,357	6,890,938	1,293,107
Shares related to the 2026 Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive securities (in shares)	7,475,897	7,475,897	0
Shares committed under the 2021 ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive securities (in shares)	193,977	108,331	0