Stockholders' Equity - Summary of Stock Option Activity (Detail) - Non Qualified Stock Option [Member] $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares	Jun. 30, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares, Options Beginning Balance | shares	5,404	5,497
Shares, Granted | shares	3	484
Shares, Exercised | shares	(385)	(921)
Shares, Forfeited | shares	(32)	(70)
Shares, Options Ending Balance | shares	4,990	4,990
Shares, Options exercisable Ending Balance | shares	4,075	4,075
Shares, Options expected to vest | shares	915	915
Weighted Average Option Exercise Price Per Share, Options Beginning Balance | $ / shares	$ 12.65	$ 10.33
Weighted Average Option Exercise Price Per Share, Granted | $ / shares	42.32	38.00
Weighted Average Option Exercise Price Per Share, Exercised | $ / shares	6.65	9.24
Weighted Average Option Exercise Price Per Share, Forfeited or expired | $ / shares	28.16	23.83
Weighted Average Option Exercise Price Per Share, Options Ending Balance | $ / shares	13.03	13.03
Weighted Average Option Exercise Price Per Share, Options exercisable Ending Balance | $ / shares	8.50	8.50
Weighted Average Option Exercise Price Per Share, Options expected to vest | $ / shares	$ 33.16	$ 33.16
Weighted Average Remaining Contractual Term in Years, Options outstanding		4 years 8 months 12 days
Weighted Average Remaining Contractual Term in Years, Options exercisable		3 years 9 months 18 days
Weighted Average Remaining Contractual Term in Years, Options expected to vest		8 years 10 months 25 days
Aggregate Intrinsic Value, Options outstanding as of June 30, 2017 | $	$ 124,780	$ 124,780
Aggregate Intrinsic Value, Options exercisable at June 30, 2017 | $	120,313	120,313
Aggregate Intrinsic Value, Options expected to vest | $	$ 4,467	$ 4,467