Equity Compensation Plans (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Shares
Outstanding at March 31, 2015	539
Exercisable at March 31, 2015	261
Expected to Vest at March 31, 2015	218
Weighted-Average Exercise Price (usd per share)
Outstanding at March 31, 2015	$ 15.35
Exercisable at March 31, 2015	$ 9.96
Expected to Vest at March 31, 2015	$ 20.61
Weighted- Average Remaining Contractual Term (years)
Outstanding at March 31, 2015	6 years 11 months 0 days
Exercisable at March 31, 2015	5 years 0 months 0 days
Expected to Vest at March 31, 2015	8 years 8 months 0 days
Aggregate Intrinsic Value
Outstanding at March 31, 2015	$ 8,816
Exercisable at March 31, 2015	5,684
Expected to Vest at March 31, 2015	$ 2,421