Net loss per share - Potentially Dilutive Securities Excluded From Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Securities excluded from computation of diluted net loss per share (in shares)	4,919	6,001
Employee stock options
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Securities excluded from computation of diluted net loss per share (in shares)	1,205	1,897
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Securities excluded from computation of diluted net loss per share (in shares)	3,340	3,365
Market-based restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Securities excluded from computation of diluted net loss per share (in shares)	134	305
Performance-based restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Securities excluded from computation of diluted net loss per share (in shares)	240	90
Employee stock purchase plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Securities excluded from computation of diluted net loss per share (in shares)	0	344