Equity Incentive Plans - Summary of Stock Option and Restricted Stock Bonus Activities (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding Beginning Balance, Number of Restricted Stock Bonuses			291,061
Granted, Number of Restricted Stock Bonuses	0	0	0
Released from restriction, Number of Restricted Stock Bonuses			(287,596)
Forfeited, Number of Restricted Stock Bonuses			(3,465)
Exercised, Number of Restricted Stock Bonuses	0	0	0
Outstanding Ending Balance, Number of Restricted Stock Bonuses				291,061
Outstanding Beginning Balance, Number of Options	3,077,481	2,008,960	1,957,760
Granted, Number of Options	455,000	1,319,500	181,125
Released from restriction, Number of Options			0
Forfeited, Number of Options	(8,360)	(95,271)	(39,920)
Exercised, Number of Options	(579,476)	(155,708)	(90,005)
Outstanding Ending Balance, Number of Options	2,944,645	3,077,481	2,008,960	1,957,760
Vested and expected to vest, Number of Options	2,916,184	3,021,937	1,974,611
Exercisable, Number of Options	1,946,475	1,726,891	1,212,445
Outstanding Beginning Balance, Weighted Average Exercise Price of Stock Options	$ 7.35	$ 6.79	$ 6.32
Granted, Weighted Average Exercise Price of Stock Options	$ 17.08	$ 8.29	$ 11.68
Forfeited, Weighted Average Exercise Price of Stock Options	$ 10.89	$ 11.07	$ 8.37
Exercised, Weighted Average Exercise Price of Stock Options	$ 7.44	$ 5.88	$ 5.88
Outstanding Ending Balance, Weighted Average Exercise Price of Stock Options	$ 8.82	$ 7.35	$ 6.79	$ 6.32
Vested and expected to vest, Weighted Average Exercise Price of Stock Options	$ 8.78	$ 7.32	$ 6.75
Exercisable, Weighted Average Exercise Price of Stock Options	$ 7.00	$ 6.54	$ 6.37
Outstanding Beginning Balance, Aggregate Intrinsic Value of Stock Options	$ 26,385	$ 2,773	$ 14,158
Outstanding Ending Balance, Aggregate Intrinsic Value of Stock Options	31,558	26,385	2,773	14,158
Vested and expected to vest, Aggregate Intrinsic Value of Stock Options	31,376	25,988	2,742
Exercisable, Aggregate Intrinsic Value of Stock Options	$ 24,325	$ 16,203	$ 1,819
Outstanding, Weighted Average Remaining Contractual Life of Stock Options	7 years 3 months 18 days	7 years 10 months 24 days	8 years 1 month 6 days	9 years
Vested and expected to vest, Weighted Average Remaining Contractual Life of Stock Options	7 years 3 months 18 days	7 years 10 months 24 days	8 years 1 month 6 days
Exercisable, Weighted Average Remaining Contractual Life of Stock Options	6 years 8 months 12 days	7 years	8 years 1 month 6 days