CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Oxide plant lease		$ 1,730	$ 1,692	$ 3,367	$ 3,336
Total revenue		1,730	1,692	3,367	3,336
Costs and expenses:
Oxide plant lease costs		(525)	(548)	(1,028)	(1,085)
Exploration expense		(1,041)	(457)	(1,940)	(991)
El Quevar project expense		(281)	(192)	(553)	(341)
Velardena shutdown and care and maintenance costs		(492)	(369)	(981)	(719)
Administrative expense		(822)	(872)	(1,883)	(1,898)
Stock based compensation		(235)	(242)	(250)	(307)
Reclamation expense		(52)	(48)	(103)	(97)
Other operating income, net		224	705	1,450	862
Depreciation and amortization		(264)	(130)	(560)	(318)
Total costs and expenses		(3,488)	(2,153)	(5,848)	(4,894)
Loss from operations		(1,758)	(461)	(2,481)	(1,558)
Other income and (expense):
Interest and other income, net		110	4	113	22
(Loss) gain on foreign currency		(41)	(3)	(56)	3
Total other income		69	1	57	25
Loss from operations before income taxes		(1,689)	(460)	(2,424)	(1,533)
Net loss		(1,689)	(460)	(2,424)	(1,533)
Comprehensive loss, net of tax:
Unrealized loss on securities			(51)		(103)
Comprehensive loss		$ (1,689)	$ (511)	$ (2,424)	$ (1,636)
Net loss per common share — basic
Loss (in dollars per share)		$ (0.02)	$ (0.01)	$ (0.03)	$ (0.02)
Weighted average common stock outstanding - basic (in shares)	[1]	93,681,301	89,618,677	92,709,238	89,485,223

[1] Potentially dilutive shares have not been included because to do so would be anti-dilutive.