Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Options outstanding beginning	1,715	2,991
Shares, Granted	124	41
Shares, Exercised	(320)	(1,096)
Shares, Cancelled	(89)	(221)
Shares, Options outstanding ending	1,430	1,715
Shares, Vested or expected to vest	1,425
Shares, Exercisable	1,148
Weighted Average Exercise Price, Options outstanding beginning	$ 12.97	$ 12.91
Weighted Average Exercise Price, Granted	17.02	13.86
Weighted Average Exercise Price, Exercised	6.90	11.43
Weighted Average Exercise Price, Cancelled	5.48	20.08
Weighted Average Exercise Price, Options outstanding ending	15.10	$ 12.97
Weighted Average Exercise Price, Vested or expected to vest	15.10
Weighted Average Exercise Price, Exercisable	$ 16.44
Aggregate Intrinsic Value, Options outstanding ending	$ 5,953
Aggregate Intrinsic Value, Vested or expected to vest	5,935
Aggregate Intrinsic Value, Exercisable	$ 3,628
Weighted Average Remaining Term, Options outstanding ending, years	4 years 15 days
Weighted Average Remaining Term, Vested or expected to vest, years	4 years 7 days
Weighted Average Remaining Term, Exercisable, years	3 years 1 month 13 days