Property, Plant and Equipment, Net - Disposals (Details)			1 Months Ended		3 Months Ended		20 Months Ended
	May 02, 2017 USD ($)	Mar. 31, 2017 USD ($)	Feb. 28, 2018 USD ($)	Aug. 31, 2016 USD ($) item	Mar. 31, 2018 USD ($) payment	Mar. 31, 2017 USD ($)	Mar. 31, 2018 USD ($)
Property, plant and equipment
Proceeds from sale of assets					$ 1,249,000	$ 115,000
Gain on sale of assets					1,115,000	115,000
Sale, not discontinued operations | Sale of Equipment
Property, plant and equipment
Number of haul trucks sold | item				2
Number of scoop trams sold | item				2
Sale of mining equipments		$ 185,000		$ 687,000
Proceeds from sale of assets	$ 750,000	$ 100,000		$ 69,000
Sales price received (as a percent)				10.00%
Related party receivable				$ 618,000
Interest rate on receivable (as a percent)		10.00%		10.00%
Gain on sale of assets						$ 105,000
Celaya | Sale, not discontinued operations
Property, plant and equipment
Proceeds from sale of assets				$ 200,000
Gain on sale of assets					1,000,000
Interest in joint venture (as a percent)			20.00%	40.00%
Exploration expenditures in first three year of the agreement				$ 2,500,000
Initial term of agreement				3 years
Term of second agreement			3 years	3 years
Net profit interest			10.00%
Celaya | Electrum | Sale, not discontinued operations
Property, plant and equipment
Earn-in to be received			$ 1,000,000	$ 500,000
Interest in joint venture (as a percent)			80.00%	60.00%
Exploration expenditures in first three year of the agreement				$ 2,500,000
Additional interest in joint venture (as a percent)			20.00%
Exploration expenditures in second three year of the agreement			$ 2,500,000
Contribution from additional expenditures required in the second three-year earn-in period (as a percent)			100.00%
Zacatecas | Sale, not discontinued operations
Property, plant and equipment
Proceeds from sale of assets					249,000		$ 1,100,000
Gain on sale of assets					115,000
Total consideration				$ 1,500,000	$ 1,500,000		1,500,000
Number of additional payments | payment					2
Payment to be received					$ 225,000		225,000
Unearned performance obligation					$ 183,000		$ 183,000