Stock Plans - Summary of Option Activity under Plans and Related Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Stock Options Outstanding, Beginning balance	1,570,765
Number of Stock Options Outstanding, Granted	0
Number of Stock Options Outstanding, Exercised	(138,126)
Number of Stock Options Outstanding, Cancelled or forfeited	(73,595)
Number of Stock Options Outstanding, Ending balance	1,359,044	1,570,765
Number of Shares, Vested and expected to vest	1,359,044
Number of Shares, Exercisable	912,169
Weighted Average Exercise Price of Stock Options Outstanding	$ 40.29	$ 39.64
Weighted Average Exercise Price, Granted	0
Weighted Average Exercise Price, Exercised	29.14
Weighted Average Exercise Price, Cancelled or forfeited	47.34
Weighted Average Exercise Price, Vested and expected to vest	40.29
Weighted Average Exercise Price, Exercisable	$ 38.20
Weighted-Average Remaining Contractual Term (in years)	6 years 6 months 4 days	6 years 10 months 24 days
Weighted-Average Remaining Contractual Term (in years), Vested and expected to vest	6 years 6 months 4 days
Weighted-Average Remaining Contractual Term (in years), Exercisable	5 years 11 months 12 days
Aggregate Intrinsic Value	$ 9,272	$ 9,226
Aggregate Intrinsic Value, Vested and expected to vest	9,272
Aggregate Intrinsic Value, Exercisable	$ 7,527