COMMITMENTS AND CONTINGENCIES - Loss Contingencies (Details)		1 Months Ended			12 Months Ended
	Dec. 28, 2016 item	Dec. 31, 2019 USD ($) item	Nov. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) item	Sep. 27, 2019 USD ($)	Aug. 19, 2019 USD ($)	Aug. 18, 2019 USD ($)	Apr. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 21, 2015 USD ($)
Loss Contingencies
Provision for post closure reclamation and remediation costs		$ 1,953,000			$ 1,953,000					$ 1,769,000	$ 2,800,000
Loss contingency accrual		14,000,000			14,000,000
Permitting Considerations
Loss Contingencies
Number of SEIS process publications in the Federal Register | item	3
Provision for post closure reclamation and remediation costs		$ 3,100,000			$ 3,100,000						$ 2,800,000
Environmental analysis, process term					3 years
Additional cash deposit									$ 300,000
Payment to trust					$ 300,000
Water Rights Considerations
Loss Contingencies
The number of additional parties in suit | item					2
Number of water rights holders in Diamond Valley | item		2			2
Ranchers
Loss Contingencies
Source from available cash					$ 500,000
Proceeds from private placement used					500,000
Mt. Hope Project
Loss Contingencies
Sustainability Trust fund asset amount								$ 4,000,000
Eureka Moly LLC
Loss Contingencies
Additional cash deposit		$ 400,000			400,000					$ 400,000
Sustainability Trust fund asset amount							$ 5,600,000	$ 4,000,000
Paid into trust		100,000			100,000
Eureka Moly LLC | Eureka County and the DNR
Loss Contingencies
Amount paid upon execution of the settlement					50,000
Second payment payable after receipt of the water permits		50,000			50,000
Additional contributions will be made after the commencement of production		750,000			750,000
Sustainability Trust fund asset amount		5,600,000			5,600,000
Amount of increase in Sustainability Trust fund asset amount		1,600,000			1,600,000
Paid into trust		100,000			100,000
Eureka Moly LLC | Ranchers
Loss Contingencies
Payment to trust					$ 1,000,000
Threshold period to secure project financing					12 months
Monthly payments until financing is achieved					$ 10,000
Source from available cash					500,000
Proceeds from private placement used					500,000
Advance from proceeds of ongoing sales of non-critical EMLLC assets and lands		1,000,000			1,000,000
LLC Agreement | Ranchers
Loss Contingencies
Loss contingency accrual		14,000,000			$ 14,000,000
Land and Water Rights | Eureka Moly LLC
Loss Contingencies
Amount owed to the company						$ 700,000
Reimbursement of debt			$ 200,000	$ 200,000
Land and Water Rights | LLC Agreement
Loss Contingencies
Reimbursement of debt		$ 300,000
Equipment | Eureka Moly LLC | Minimum
Loss Contingencies
Sale of equipment			$ 400,000