Stock-Based Compensation - Summary of Stock Options (Detail) (2004 Stock Option Plan [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
2004 Stock Option Plan [Member]
Stock Options [Line Items]
Number of Shares, Outstanding beginning balance	737,291
Number of Shares, Granted
Number of Shares, Exercised	(648,845)
Number of Shares, Forfeited or expired
Number of Shares, Outstanding ending balance	88,446
Number of Shares, Exercisable	88,446
Number of Shares, Vested and expected to vest	88,446
Weighted-Average Exercise Price, Outstanding beginning balance	$ 2.96
Weighted-Average Exercise Price, Granted
Weighted-Average Exercise Price, Exercised	$ 2.81
Weighted-Average Exercise Price, Forfeited or expired
Weighted-Average Exercise price, Outstanding ending balance	$ 4.04
Weighted-Average Exercise Price, Exercisable	$ 4.04
Weighted-Average Exercise Price, Vested and expected to vest	$ 4.04
Weighted-Average Remaining Contractual Term, Outstanding ending balance	9 months 22 days
Weighted-Average Remaining Contractual Term, Exercisable	9 months 22 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	9 months 22 days
Aggregate Intrinsic Value, Outstanding ending balance	$ 203
Aggregate Intrinsic Value, Exercisable	203
Aggregate Intrinsic Value, Vested and expected to vest	$ 203