Mineral Properties - Additional Information (Details)	3 Months Ended	9 Months Ended
	Mar. 31, 2017 USD ($) a MiningClaim	Mar. 31, 2017 USD ($) a MiningClaim
Mineral Properties [Line Items]
Gain on sale of non-core mining claims | $	$ 100,000	$ 100,000
Sleeper Gold Project | Nevada
Mineral Properties [Line Items]
Unpatented mining claims	2,322	2,322
Area covered by lode mining claims | a	38,300	38,300
Grassy Mountain Project | Oregon
Mineral Properties [Line Items]
Unpatented lode mining claims	418	418
Patented lode mining claims	3	3
Mill site mining claims	9	9
Association placer claims	6	6
Area covered by mining claims | a	9,300	9,300