SHARE-BASED COMPENSATION - RSU Activity - Summary of Change (Details)	6 Months Ended
	Jun. 30, 2018 USD ($) $ / shares shares
Number of Restricted Stock Units [Roll Forward]
RSUs beginning	4,285,290
RSUs awarded	1,279,660
RSUs assumed in Merger	0
RSUs released	(1,485,340)
RSUs forfeited	(238,606)
RSUs ending	3,841,004
Weighted Average Purchase Price RSUs | $ / shares	$ 0
Weighted Average Remaining Contractual Term (Years) RSUs	1 year 7 months 6 days
Aggregate Intrinsic Value RSUs | $	$ 28,811,490
Number of RSUs vested and expected to vest	3,840,828
Weighted Average Purchase Price of RSUs vested and expected to vest | $ / shares	$ 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 | $	$ 28,806,210
Number of RSUs exercisable	48,880
Weighted Average Purchase Price of RUSs exercisable | $ / shares	$ 0
Weighted Average Remaining Contractual Term (Years) of RUSs exercisable	0 years
Aggregate Intrinsic Value RSUs exercisable | $	$ 366,600
Weighted average remaining recognition period in years	2 years 4 months 24 days
Unamortized compensation expense, net of estimated forfeitures | $	$ 30,158,160