Geographic and Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Net property, plant and equipment	$ 35,375		$ 35,409
Restricted cash	3,668		3,668
Notes receivable, non-current	2,548		3,328
Mineral property expenses	(782)	$ (769)
General and administrative	1,805	1,668
Acquisition related expenses	(755)
Accretion of asset retirement costs	(134)	(132)	(1,039)
Depreciation and amortization	(34)	(38)
Total operating expenses	(3,510)	(2,607)
Other income (expense)	91	$ 4,452
Long Term Assets [Member]
Net property, plant and equipment	35,375		35,409
Restricted cash	3,668		3,668
Notes receivable, non-current	2,548		3,328
Total long-term assets	41,591		42,405
Operating Results [Member]
Mineral property expenses	782		769
General and administrative	1,805		1,668
Acquisition related expenses	755
Accretion of asset retirement costs	134		132
Depreciation and amortization	34		38
Total operating expenses	3,510		2,607
Loss from operations	(3,510)		(2,607)
Other income (expense)	91		4,452
Loss before taxes	(3,419)		1,845
Corporate [Member] | Long Term Assets [Member]
Net property, plant and equipment	198		211
Restricted cash
Notes receivable, non-current	1,431		834
Total long-term assets	1,629		1,045
Corporate [Member] | Operating Results [Member]
Mineral property expenses
General and administrative	1,353		1,312
Acquisition related expenses	755
Accretion of asset retirement costs
Depreciation and amortization	1		1
Total operating expenses	2,109		1,313
Loss from operations	(2,109)		(1,313)
Other income (expense)	81		(39)
Loss before taxes	(2,028)		(1,352)
Uranium [Member] | Long Term Assets [Member]
Net property, plant and equipment	35,177		35,198
Restricted cash	3,668		3,668
Notes receivable, non-current	1,117		2,494
Total long-term assets	39,962		41,360
Uranium [Member] | Operating Results [Member]
Mineral property expenses	774		648
General and administrative	452		356
Acquisition related expenses
Accretion of asset retirement costs	134		132
Depreciation and amortization	33		37
Total operating expenses	1,393		1,173
Loss from operations	(1,393)		(1,173)
Other income (expense)	10		4,491
Loss before taxes	(1,383)		3,318
Lithium [Member] | Long Term Assets [Member]
Net property, plant and equipment
Restricted cash
Notes receivable, non-current
Total long-term assets
Lithium [Member] | Operating Results [Member]
Mineral property expenses	8		121
General and administrative
Acquisition related expenses
Accretion of asset retirement costs
Depreciation and amortization
Total operating expenses	8		121
Loss from operations	(8)		(121)
Other income (expense)
Loss before taxes	$ (8)		$ (121)