Net Income (Loss) per Share - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income (loss) - Basic and Diluted	$ 78,909	$ (16,509)	$ (25,068)	$ (28,922)	$ (28,611)	$ (32,842)	$ (22,960)	$ (21,960)	$ 8,410	$ (106,373)	$ (74,013)
Weighted-average common shares outstanding:
Weighted average common shares outstanding - Basic									47,413,250	42,669,333	35,892,786
Stock options									481,254
Restricted stock units									20,526
Weighted-average common shares outstanding - diluted									47,915,030	42,669,333	35,892,786
Net income (loss) per share:
Basic	$ 1.60	$ (0.35)	$ (0.54)	$ (0.62)					$ 0.18	$ (2.49)	$ (2.06)
Diluted	$ 1.59	$ (0.35)	$ (0.54)	$ (0.62)					$ 0.18	$ (2.49)	$ (2.06)