Stockholders' Equity - Summary of Restricted Stock Unit Activity (Detail) - Restricted Stock $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Number of Units outstanding, beginning of year (in shares) | shares	1,330
Number of Units, Granted (in shares) | shares	989
Number of Units, Released (in shares) | shares	(350)
Number of Units, Forfeited (in shares) | shares	(46)
Number of Units outstanding, end of period (in shares) | shares	1,923
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Grant Date Fair Value, Units outstanding, beginning of year (in dollars per share) | $ / shares	$ 20.40
Weighted Average Grant Date Fair Value, Granted (in dollars per share) | $ / shares	25.17
Weighted Average Grant Date Fair Value, Released (in dollars per share) | $ / shares	18.68
Weighted Average Grant Date Fair Value, Forfeited (in dollars per share) | $ / shares	23.56
Weighted Average Grant Date Fair Value, Units outstanding, end of period (in dollars per share) | $ / shares	$ 23.08
Aggregate intrinsic value at end of period | $	$ 48,344