The Company and Significant Accounting Policies - Reconciliation of Basic and Diluted Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share Basic And Diluted [Abstract]
Net income (loss)	$ (12,217)	$ (16,279)	$ 1,424	$ 2,215	$ 4,840	$ (1,808)	$ (27,072)	$ 5,248
Denominator:
Weighted average common shares outstanding, basic	84,765,694			88,852,342			85,404,250	89,371,750
Basic earnings per share:
Net income (loss) per share	$ (0.14)			$ 0.02			$ (0.32)	$ 0.06
Denominator:
Weighted average common shares outstanding, basic	84,765,694			88,852,342			85,404,250	89,371,750
Dilutive securities:
Stock options and restricted stock units				1,270,083				1,202,913
Weighted average common shares outstanding, diluted	84,765,694			90,122,425			85,404,250	90,574,663
Diluted earnings per share:
Net income (loss) per share	$ (0.14)			$ 0.02			$ (0.32)	$ 0.06