Net Loss per Share - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ 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	$ (25,068)	$ (28,922)	$ (22,960)	$ (21,960)	$ (53,990)	$ (44,920)
Weighted-average common shares outstanding:
Basic and Diluted	46,799,703		39,818,162		46,762,327	39,685,954
Net loss per share, Basic and Diluted	$ (0.54)		$ (0.58)		$ (1.15)	$ (1.13)