Property, Plant and Equipment, Net (Details)				3 Months Ended		9 Months Ended
	Aug. 08, 2016 USD ($) item	Aug. 02, 2016 USD ($) shares	Apr. 28, 2016 USD ($)	Sep. 30, 2016 USD ($) shares	Mar. 31, 2015 USD ($) shares	Sep. 30, 2016 USD ($) shares	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2012 USD ($)
Property, plant and equipment
Property, plant and equipment, gross				$ 34,960,000		$ 34,960,000		$ 35,849,000
Less: Accumulated depreciation & amortization				(25,507,000)		(25,507,000)		(24,724,000)
Property, plant and equipment, net				9,453,000		9,453,000		11,125,000
Gain on sale of equipment						1,522,000	$ 367,000
Proceeds from sale of assets						898,000	$ 416,000
Related party receivable				$ 642,000		$ 642,000
Golden Tag
Property, plant and equipment
Shares received | shares		2,500,000		250,000	5,000,000	7,500,000
Additional interest in joint venture (as a percent)		10.00%		10.00%		10.00%
Mineral properties
Property, plant and equipment
Property, plant and equipment, gross				$ 9,575,000		$ 9,575,000		9,630,000
Exploration properties
Property, plant and equipment
Property, plant and equipment, gross				2,518,000		2,518,000		2,518,000
Royalty properties
Property, plant and equipment
Property, plant and equipment, gross				200,000		200,000		200,000
Buildings
Property, plant and equipment
Property, plant and equipment, gross				4,386,000		4,386,000		4,377,000
Mining equipment and machinery
Property, plant and equipment
Property, plant and equipment, gross				16,337,000		16,337,000		16,998,000
Other furniture and equipment
Property, plant and equipment
Property, plant and equipment, gross				952,000		952,000		841,000
Asset retirement cost
Property, plant and equipment
Property, plant and equipment, gross				992,000		992,000		$ 1,285,000
Sale of Equipment | Minera Inde
Property, plant and equipment
Property, plant and equipment, net	$ 27,000
Number of haul trucks sold | item	2
Number of scoop trams sold | item	2
Sale of mining equipments	$ 687,000
Gain on sale of equipment	660,000
Proceeds from sale of assets	$ 69,000					69,000
Percentage of sales price received	10.00%
Related party receivable	$ 618,000			627,000		$ 627,000
Interest on receivable (as a percent)	10.00%
Velardena properties | Asset retirement cost
Property, plant and equipment
Property, plant and equipment, net									$ 1,900,000
San Diego
Property, plant and equipment
Property, plant and equipment, net		$ 0
Gain on sale of equipment		500,000
Proceeds from sale of assets		$ 379,000
Ownership in property (as a percent)		50
San Diego | Golden Tag
Property, plant and equipment
Proceeds from sale of assets				$ 379,000
Ownership in property (as a percent)		50		50
Net smelter return royalty (as a percent)		2.0
Additional interest in joint venture (as a percent)					10.00%
Additional payments in joint venture					$ 800,000
Celaya | Electrum
Property, plant and equipment
Gain on sale of equipment				$ 200,000
Proceeds from sale of assets				200,000
Celaya | Electrum | Minimum
Property, plant and equipment
Additional payments in joint venture				$ 500,000
Zacatecas Properties | Santa Cruz
Property, plant and equipment
Gain on sale of equipment			$ 200,000
Proceeds from sale of assets			200,000
Amount of agreement to sell property			1,500,000
Due six months after signing agreement			200,000
Due 12 months after signing agreement			300,000
Due 18 months after signing agreement			300,000
Due 24 months after signing agreement			$ 500,000