Stockholders' Equity - Summary of Option Activity (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding at beginning of period	4,192,927
Number of Shares, Granted	152,265
Number of Shares, Exercised	(1,337,878)
Number of Shares, Forfeitures
Number of Shares, Outstanding at end of period	3,007,314
Weighted Average Exercise Price Per Share, Outstanding at beginning of period	$ 3.82
Weighted average Exercise Price Per Share, Exercised	$ 3.48
Weighted Average Exercise Price Per Share, Forfeitures
Weighted Average Exercise Price Per Share, Outstanding at end of period	$ 4.26
Aggregate Intrinsic Value, Outstanding at beginning of period
Aggregate Intrinsic Value, Outstanding at end of period	$ 38,598,170
Officers and Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted
Weighted Average Exercise Price Per Share, Granted
Others [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Granted	152,265
Weighted Average Exercise Price Per Share, Granted	$ 9.41