SHARE-BASED COMPENSATION - RSU Activity - Summary of Change (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Number of Restricted Stock Units [Roll Forward]
RSUs beginning	1,258,685
RSUs awarded	645,601
RSUs released	(336,229)
RSUs forfeited	(13,499)
RSUs ending	1,554,558
Weighted Average Purchase Price RSUs	$ 0
Weighted Average Remaining Contractual Term (Years) RSUs	1 year 8 months 12 days
Aggregate Intrinsic Value RSUs	$ 18,887,880
Number of RSUs vested and expected to vest	1,414,787
Weighted Average Purchase Price of RSUs vested and expected to vest	$ 0
Weighted Average Remaining Contractual Term (Years) of RUSs vested and expected to vest	1 year 7 months 6 days
Aggregate Intrinsic Value RSUs vested and expected to vest	16,161,731
Number of RSUs exercisable	84,603
Weighted Average Purchase Price of RUSs exercisable	$ 0
Weighted Average Remaining Contractual Term (Years) of RUSs exercisable	0 years
Aggregate Intrinsic Value RSUs exercisable	1,027,926
Weighted average remaining recognition period in years	2 years 4 months 24 days
Unamortized compensation expense, net of estimated forfeitures	$ 10,435,775