Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Paid-In Capital [Member]	Accumulated Other Comprehensive Gain (Loss) [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2016	$ 17	$ 280,191		$ (236,902)	$ (258)	$ 43,048
Balance, shares at Dec. 31, 2016	16,667,394
Net loss				(19,288)		(19,288)
Common stock issued, net of issuance costs	$ 10	15,311				15,321
Common stock issued, net of issuance costs, shares	9,926,396
Common stock issued for settlement of accounts payable		325				325
Common stock issued for settlement of accounts payable, shares	177,700
Common stock issued for purchase of lithium mineral interests		110				110
Common stock issued for purchase of lithium mineral interests, shares	100,000
Common stock issued for commitment fees	$ 1	1,213				1,214
Common stock issued for commitment fees, shares	880,000
Stock compensation expense and related share issuances, net of shares withheld for payment of taxes		101				101
Stock compensation expense and related share issuances, net of shares withheld for payment of taxes, shares	38,834
Minimum withholding taxes on net share settlements of equity awards		(1)				(1)
Unrealized holding gain loss on marketable securities			287			287
Transfer to realized loss upon sale of available-for-sale securities
Balance at Dec. 31, 2017	$ 28	297,250	287	(256,190)	(258)	41,117
Balance, shares at Dec. 31, 2017	27,790,324
Net loss				(35,684)		(35,684)
Common stock issued, net of issuance costs	$ 32	8,683				8,715
Common stock issued, net of issuance costs, shares	32,018,551
Common stock issued for consulting services		95				95
Common stock issued for consulting services, shares	172,727
Common stock issued for purchase of lithium mineral interests		114				114
Common stock issued for purchase of lithium mineral interests, shares	200,000
Common stock, warrants and options issued for acquisition of Alabama Graphite	$ 12	6,472				6,484
Common stock, warrants and options issued for acquisition of Alabama Graphite, shares	11,625,210
Stock compensation expense and related share issuances, net of shares withheld for payment of taxes		332				332
Stock compensation expense and related share issuances, net of shares withheld for payment of taxes, shares	20,931
Minimum withholding taxes on net share settlements of equity awards		(5)				(5)
Unrealized holding gain loss on marketable securities			(861)			(861)
Transfer to realized loss upon sale of available-for-sale securities			484			484
Balance at Dec. 31, 2018	$ 72	$ 312,941	$ (90)	$ (291,874)	$ (258)	$ 20,791
Balance, shares at Dec. 31, 2018	71,827,743