Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net loss	$ (32,393)	$ (31,806)	$ (25,683)	$ (21,940)	$ (64,199)	$ (47,623)
Weighted average shares outstanding, basic and diluted	53,369		45,814		51,938	45,526
Net loss per share, basic and diluted	$ (0.61)		$ (0.56)		$ (1.24)	$ (1.05)