Net loss per share - Antidilutive Securities Excluded from Computation of Net Income per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share (shares)		10,598	1,682	14,652
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)		10,598	1,682	14,652
Share-based Payment Arrangement
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share (shares)	1,772
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	1,772