Net Loss Per Share - Anti-dilutive shares excluded from the calculation of diluted net loss per share (Details) - shares shares in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders
Total shares excluded from net loss per share	16,842	18,395
Options to purchase common stock
Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders
Total shares excluded from net loss per share	5,420	9,312
Common stock warrants
Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders
Total shares excluded from net loss per share	0	510
Non-vested restricted stock unit awards
Anti-dilutive shares excluded from the calculation of diluted net loss per share attributable to common stockholders
Total shares excluded from net loss per share	11,422	8,573