Revenue and Related Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Oxide plant lease	$ 1,729		$ 4,768
Lease related costs	$ 549		1,478
Deferred revenue					$ 500
Sale of metals		$ 1,788		$ 6,086
Inventory write down charged to cost of metals sold				100
Velardena properties
Sale of metals			0
Velardena properties | Oxide Plant Lease Agreement
Oxide plant lease			4,800	0
Lease related costs			$ 1,500	$ 0
Advance lease amounts received					500
Deferred revenue					$ 500