SUPPLEMENTAL FINANCIAL INFORMATION - Schedule of Other Nonoperating Income (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest income	$ 482	$ 336	$ 161
Change in value of investments accounted for at fair value	(153)	769	509
Change in value of warrant liabilities	3,726	(3,469)	784
Change in value of Convertible Debentures	291	(612)	(940)
Foreign exchange loss	(46)	0	0
Sales and property tax refunds	0	341	0
Sale of surplus assets	0	293	1,913
Other	(322)	14	142
Other income (loss)	$ 3,978	$ (2,328)	$ 2,569