Net Loss Per Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net loss	$ (29,237)	$ (22,924)	$ (58,884)	$ (47,174)
Denominator:
Weighted-average shares outstanding - basic and diluted	146,242	138,777	145,467	137,844
Net loss per common share - basic and diluted:	$ (0.20)	$ (0.17)	$ (0.40)	$ (0.34)