Stock-Based Compensation - Summary of Stock Option Activity under Company's Stock Option Plan (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options outstanding, beginning balance	5,486,687
Options Outstanding, Granted	10,000
Options Outstanding, Exercised	(566,838)
Options Outstanding, Forfeited	(33,125)
Options Outstanding, Canceled	(429,476)
Options outstanding, ending balance	4,467,248
Options Outstanding, Options exercisable	4,427,873
Options Outstanding, Options vested or expected to vest	4,462,875
Weighted- Average Exercise Price Per Share, Options outstanding, beginning balance	$ 6.88
Weighted- Average Exercise Price Per Share, Granted	$ 7.03
Weighted- Average Exercise Price Per Share, Exercised	$ 2.75
Weighted- Average Exercise Price Per Share, Forfeited	$ 6.44
Weighted- Average Exercise Price Per Share, Canceled	$ 7.98
Weighted- Average Exercise Price Per Share, Options outstanding, ending balance	$ 7.30
Weighted- Average Exercise Price Per Share, Options exercisable	$ 7.30
Weighted- Average Exercise Price Per Share, Options vested or expected to vest	$ 7.30
Weighted- Average Remaining Contractual Term in Years, Options outstanding	3 years 4 months 24 days
Weighted- Average Remaining Contractual Term in Years, Options exercisable	3 years 3 months 18 days
Weighted- Average Remaining Contractual Term in Years, Options vested or expected to vest	3 years 4 months 24 days
Aggregate Intrinsic Value, Options outstanding	$ 2,416
Aggregate Intrinsic Value, Options exercisable	2,411
Aggregate Intrinsic Value, Options vested or expected to vest	$ 2,415