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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net loss	$ (22,924)	$ (18,478)	$ (47,174)	$ (36,255)
Denominator:
Weighted-average shares outstanding - basic and diluted	138,777	131,099	137,844	128,943
Net loss per common share - basic and diluted:	$ (0.17)	$ (0.14)	$ (0.34)	$ (0.28)