Geographic and Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Net property, plant and equipment	$ 26,318		$ 26,318		$ 35,409
Restricted cash	3,668		3,668		3,668
Notes receivable, non-current	1,368		1,368		3,328
Mineral property expenses	955	$ 1,316	2,706	$ 3,637
General and administrative expenses	1,803	1,700	5,662	4,976
Acquisition costs			333
Accretion of asset retirement costs	133	132	401	395	1,039
Impairment of uranium properties			17,968
Depreciation and amortization	27	27	94	104
Total operating expenses	2,918	3,175	27,164	9,112
Other (expense) income	(219)	192	152	5,334
Long Term Assets [Member]
Net property, plant and equipment	26,318		26,318		35,409
Restricted cash	3,668		3,668		3,668
Notes receivable, non-current	1,368		1,368		3,328
Total long-term assets	31,354		31,354		42,405
Operating Results [Member]
Mineral property expenses	955	1,316	2,706	3,637
General and administrative expenses	1,803	1,700	5,662	4,976
Acquisition costs			333
Accretion of asset retirement costs	133	132	401	395
Impairment of uranium properties			17,968
Depreciation and amortization	27	27	94	104
Total operating expenses	2,918	3,175	27,164	9,112
Loss from operations	(2,918)	(3,175)	(27,164)	(9,112)
Other (expense) income	(219)	191	151	5,334
(Loss) Income before taxes	(3,137)	(2,984)	(27,013)	(3,778)
Corporate [Member] | Long Term Assets [Member]
Net property, plant and equipment	175		175		211
Restricted cash
Notes receivable, non-current					834
Total long-term assets	175		175		1,045
Corporate [Member] | Operating Results [Member]
Mineral property expenses
General and administrative expenses	1,184	1,280	3,901	3,799
Acquisition costs			333
Accretion of asset retirement costs
Impairment of uranium properties
Depreciation and amortization	1	3	3	4
Total operating expenses	1,185	1,283	4,237	3,803
Loss from operations	(1,185)	(1,283)	(4,237)	(3,803)
Other (expense) income	(246)	185	7	385
(Loss) Income before taxes	(1,431)	(1,098)	(4,230)	(3,418)
Uranium [Member] | Long Term Assets [Member]
Net property, plant and equipment	17,171		17,171		35,198
Restricted cash	3,668		3,668		3,668
Notes receivable, non-current	1,368		1,368		2,494
Total long-term assets	22,207		22,207		41,360
Uranium [Member] | Operating Results [Member]
Mineral property expenses	600	625	2,204	2,596
General and administrative expenses	478	420	1,383	1,177
Acquisition costs
Accretion of asset retirement costs	133	132	401	395
Impairment of uranium properties			17,968
Depreciation and amortization	26	24	90	100
Total operating expenses	1,237	1,201	22,046	4,268
Loss from operations	(1,237)	(1,201)	(22,046)	(4,268)
Other (expense) income	27	6	144	4,949
(Loss) Income before taxes	(1,210)	(1,195)	(21,902)	681
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	317	691	455	1,041
General and administrative expenses
Acquisition costs
Accretion of asset retirement costs
Impairment of uranium properties
Depreciation and amortization
Total operating expenses	317	691	455	1,041
Loss from operations	(317)	(691)	(455)	(1,041)
Other (expense) income
(Loss) Income before taxes	(317)	(691)	(455)	(1,041)
Graphite [Member] | Long Term Assets [Member]
Net property, plant and equipment	8,972		8,972
Restricted cash
Notes receivable, non-current
Total long-term assets	8,972		8,972
Graphite [Member] | Operating Results [Member]
Mineral property expenses	38		47
General and administrative expenses	141		378
Acquisition costs
Accretion of asset retirement costs
Impairment of uranium properties
Depreciation and amortization			1
Total operating expenses	179		426
Loss from operations	(179)		(426)
Other (expense) income
(Loss) Income before taxes	$ (179)		$ (426)