INCOME TAXES - SCHEDULE OF DEFERRED TAX ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accrued expenses	$ 5,468	$ 3,527
NOL carryforwards	135,042	12,869
Stock-based compensation	34,408	10,382
Allowance for bad debts	1,999	3,186
Deferred revenue	10,924	0
Property and equipment	650	0
Other	3,575	1,811
Total deferred tax assets	192,066	31,775
Less valuation allowance	(61,563)	(14,180)
Net deferred tax assets	130,503	17,595
Deferred tax liabilities:
Intangible and other assets	(85,227)	(1,818)
Property and equipment	0	(2,661)
Other	(179)	(133)
Total deferred tax liabilities	(85,406)	(4,612)
Net deferred tax assets	$ 45,097	$ 12,983