SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition and Inventory (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Revenue recognized on an accrual basis	$ 57,646	$ 19,579	$ 101,500	$ 33,255
Revenue recognized when cash is received		1,606	4,509	2,765
Total	57,646	$ 21,185	106,009	$ 36,020
Inventory
Raw materials	5,009		5,009		$ 2,408
Semi-finished and finished goods	7,401		7,401		4,425
Total inventory	$ 12,410		$ 12,410		$ 6,833