Stock-Based Compensation - Option Activity (Detail) (Stock Option [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Option [Member]
Shares
Outstanding, Beginning Balance	1,828	3,287	3,218
Options granted	31	120	293
Options exercised	(365)	(612)	(211)
Options canceled/forfeited	(178)	(967)	(13)
Outstanding, Ending Balance	1,316	1,828	3,287
Options exercisable	537
Options vested and expected to vest	964
Shares available for future grant	2,638
Weighted Average Exercise Price
Outstanding, Beginning Balance	$ 12.51	$ 10.72	$ 10.32
Options granted	$ 19.38	$ 15.61	$ 14.91
Options exercised	$ 11.48	$ 8.44	$ 10.22
Options canceled/forfeited	$ 13.58	$ 9.38	$ 13.48
Outstanding, Ending Balance	$ 12.81	$ 12.51	$ 10.72
Options exercisable	$ 12.13
Options vested and expected to vest	$ 12.33
Weighted Average Remaining Contractual Life
Outstanding, Contractual life	3 years 11 months 27 days
Options exercisable	2 years 6 months 15 days
Options vested and expected to vest	2 years 7 months 24 days
Aggregate Intrinsic Value
Outstanding intrinsic value	$ 9,402
Options exercisable	4,201
Options vested and expected to vest	$ 7,350