Net Loss Per Share - Computation of Basic and Diluted Net Loss 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
Earnings Per Share [Abstract]
Net loss	$ (11,960)	$ (21,628)	$ (34,937)	$ (43,068)
Weighted-average shares used to compute net loss per share (in shares)	100,209	95,820	99,532	94,785
Net loss per share, basic and diluted (in usd per share)	$ (0.12)	$ (0.23)	$ (0.35)	$ (0.45)