Stockholders' Equity - Summary of Stock Options Exercisable (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Exercisable	2,465,513
Weighted Average Remaining Contractual Life (Years)	0 years
Weighted Average Exercise Price
Aggregate Intrinsic Value	$ 32,321,327
$1.00 - 5.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$ 1.00
Range of Exercise Prices, maximum	$ 5.00
Number Exercisable	1,725,513
Weighted Average Remaining Contractual Life (Years)	4 years 8 months 9 days
Weighted Average Exercise Price	$ 2.98
Aggregate Intrinsic Value
$5.01 - 10.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$ 5.01
Range of Exercise Prices, maximum	$ 10.00
Number Exercisable	740,000
Weighted Average Remaining Contractual Life (Years)	2 years 10 months 2 days
Weighted Average Exercise Price	$ 6.35
Aggregate Intrinsic Value
$ 10.01 - 15.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$ 10.01
Range of Exercise Prices, maximum	$ 15.00
Number Exercisable
Weighted Average Remaining Contractual Life (Years)	0 years
Weighted Average Exercise Price
Aggregate Intrinsic Value
$15.01 - 20.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, minimum	$ 15.01
Range of Exercise Prices, maximum	$ 20.00
Number Exercisable
Weighted Average Remaining Contractual Life (Years)	0 years
Weighted Average Exercise Price
Aggregate Intrinsic Value