Geographic and Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Net property, plant and equipment	$ 20,553	$ 35,409
Restricted cash	3,732	3,668
Notes receivable, non-current	1,493	3,328
Mineral property expenses	3,538	4,584
General and administrative	7,357	6,614
Acquisition related expenses	333	1,003
Accretion of asset retirement costs	993	1,039
Depreciation and amortization	116	142
Impairment of uranium properties	23,712	11,436
Total operating expenses	36,049	24,818
Other income	365	5,530
Long Term Assets [Member]
Net property, plant and equipment	20,553	35,409
Restricted cash	3,732	3,668
Notes receivable, non-current	1,493	3,328
Total long-term assets	25,778	42,405
Operating Results [Member]
Mineral property expenses	3,538	4,584
General and administrative	7,357	6,614
Acquisition related expenses	333	1,003
Accretion of asset retirement costs	993	1,039
Depreciation and amortization	116	142
Impairment of uranium properties	23,712	11,436
Total operating expenses	36,049	24,818
Loss from operations	(36,049)	(24,818)
Other income	365	5,530
Loss before taxes	(35,684)	(19,288)
Corporate [Member] | Long Term Assets [Member]
Net property, plant and equipment	162	211
Restricted cash
Notes receivable, non-current		834
Total long-term assets	162	1,045
Corporate [Member] | Operating Results [Member]
Mineral property expenses
General and administrative	4,986	4,791
Acquisition related expenses	333	1,003
Accretion of asset retirement costs
Depreciation and amortization	5	5
Impairment of uranium properties
Total operating expenses	5,324	5,799
Loss from operations	(5,324)	(5,799)
Other income	196	573
Loss before taxes	(5,128)	(5,226)
Uranium [Member] | Long Term Assets [Member]
Net property, plant and equipment	11,418	35,198
Restricted cash	3,722	3,668
Notes receivable, non-current	1,493	2,494
Total long-term assets	16,633	41,360
Uranium [Member] | Operating Results [Member]
Mineral property expenses	2,917	3,383
General and administrative	1,846	1,823
Acquisition related expenses
Accretion of asset retirement costs	993	1,039
Depreciation and amortization	110	137
Impairment of uranium properties	23,712	11,436
Total operating expenses	29,578	17,818
Loss from operations	(29,578)	(17,818)
Other income	168	4,957
Loss before taxes	(29,410)	(12,861)
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	481	1,201
General and administrative
Acquisition related expenses
Accretion of asset retirement costs
Depreciation and amortization
Impairment of uranium properties
Total operating expenses	481	1,201
Loss from operations	(481)	(1,201)
Other income
Loss before taxes	(481)	(1,201)
Graphite [Member] | Long Term Assets [Member]
Net property, plant and equipment	8,973
Restricted cash	10
Notes receivable, non-current
Total long-term assets	8,983
Graphite [Member] | Operating Results [Member]
Mineral property expenses	140
General and administrative	525
Acquisition related expenses
Accretion of asset retirement costs
Depreciation and amortization	1
Impairment of uranium properties
Total operating expenses	666
Loss from operations	(666)
Other income	1
Loss before taxes	$ (665)