Stockholders' Equity - Summary of Stock Option Activity (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding at beginning of period	4,279,919	4,553,251	4,311,539
Number of Shares, Granted	278,794
Number of Shares, Exercised	(115,667)	(789,305)	(129,888)
Number of Shares, Forfeitures	(250,119)	(250,741)	(76,937)
Number of Shares, Outstanding at end of period	4,192,927	4,279,919	4,553,251
Weighted Average Exercise Price Per Share, Outstanding at beginning of period	$ 3.70	$ 3.66	$ 3.65
Weighted average Exercise Price Per Share, Exercised	$ 3.25	$ 2.60	$ 2.69
Weighted Average Exercise Price Per Share, Forfeitures	$ 2.89	$ 3.26	$ 3.09
Weighted Average Exercise Price Per Share, Outstanding at end of period	$ 3.82	$ 3.70	$ 3.66
Aggregate Intrinsic Value, Outstanding at end of period	$ 9,145,780	$ 4,572,205
Officers and Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted	55,659	281,174	209,619
Weighted Average Exercise Price Per Share, Granted	$ 5.39	$ 2.36	$ 3.44
Others [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted	223,135	485,540	238,918
Weighted Average Exercise Price Per Share, Granted	$ 4.47	$ 2.80	$ 3.41