GEOGRAPHIC AND SEGMENT INFORMATION - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Long-term assets by reportable segments
Net property, plant and equipment	$ 20,324		$ 20,337
Restricted cash	3,806		3,797
Operating lease right of use assets	454		484
Total long-term assets	24,584		24,618
Statement of Operations, Loss before taxes
Mineral property expenses	728	$ 634
General and administrative	1,779	1,705
Arbitration expenses	669	131
Accretion of asset retirement costs	106	126	390
Depreciation and amortization	13	23
Total operating expenses	3,295	2,619
Loss from operations	(3,295)	(2,619)
Other income (loss)	8	(555)
Loss before taxes	(3,287)	(3,174)
Corporate
Long-term assets by reportable segments
Net property, plant and equipment	103		114
Operating lease right of use assets	435		463
Total long-term assets	538		577
Statement of Operations, Loss before taxes
General and administrative	1,189	1,148
Arbitration expenses	669	131
Depreciation and amortization	12	1
Total operating expenses	1,870	1,280
Loss from operations	(1,870)	(1,280)
Other income (loss)		(555)
Loss before taxes	(1,870)	(1,835)
Uranium
Long-term assets by reportable segments
Net property, plant and equipment	11,249		11,251
Restricted cash	3,796		3,787
Operating lease right of use assets	19		21
Total long-term assets	15,064		15,059
Statement of Operations, Loss before taxes
Mineral property expenses	602	553
General and administrative	426	392
Accretion of asset retirement costs	106	126
Depreciation and amortization	1	22
Total operating expenses	1,135	1,093
Loss from operations	(1,135)	(1,093)
Other income (loss)	8
Loss before taxes	(1,127)	(1,093)
Lithium
Statement of Operations, Loss before taxes
Mineral property expenses		1
Total operating expenses		1
Loss from operations		(1)
Loss before taxes		(1)
Graphite
Long-term assets by reportable segments
Net property, plant and equipment	8,972		8,972
Restricted cash	10		10
Total long-term assets	8,982		$ 8,982
Statement of Operations, Loss before taxes
Mineral property expenses	126	80
General and administrative	164	165
Total operating expenses	290	245
Loss from operations	(290)	(245)
Loss before taxes	$ (290)	$ (245)