PREPAID EXPENSES AND OTHER ASSETS (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid license	$ 2,217	$ 1,919
Prepaid catalyst	620	779
Prepaid insurance	26	0
Spare parts	1,557	954
Other prepaid expenses and assets	1,046	772
Total	$ 5,466	$ 4,424