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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share Basic And Diluted [Abstract]
Net income (loss)	$ 4,840	$ 3,495	$ 3,033	$ 6,113
Denominator:
Weighted average common shares outstanding, basic	88,959,935	90,354,982	89,635,759	90,296,057
Basic earnings per share:
Net income (loss) per share	$ 0.05	$ 0.04	$ 0.03	$ 0.07
Denominator:
Weighted average common shares outstanding, basic	88,959,935	90,354,982	89,635,759	90,296,057
Dilutive securities:
Stock options and restricted stock units	1,062,014	1,678,129	1,169,327	1,601,093
Weighted average common shares outstanding, diluted	90,021,949	92,033,111	90,805,086	91,897,150
Diluted earnings per share:
Net income (loss) per share	$ 0.05	$ 0.04	$ 0.03	$ 0.07