Property, plant, and equipment and assets held-for-sale, net - Components of Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Property, Plant and Equipment [Line Items]
Plant and equipment, gross	$ 88,441	$ 87,861
Less, accumulated depreciation and amortization	(38,329)	(36,273)
Total	50,112	51,588
Assets held-for-sale	2,893	5,698
Total	53,005	57,286
Production leach pads
Property, Plant and Equipment [Line Items]
Plant and equipment, gross	$ 11,190	11,190
Test leach pads
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	18 months
Plant and equipment, gross	$ 6,241	6,241
Process equipment
Property, Plant and Equipment [Line Items]
Plant and equipment, gross	$ 18,029	18,030
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	10 years
Plant and equipment, gross	$ 9,536	9,446
Mine equipment
Property, Plant and Equipment [Line Items]
Plant and equipment, gross	5,143	5,050
Vehicles
Property, Plant and Equipment [Line Items]
Plant and equipment, gross	$ 1,854	1,854
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	7 years
Plant and equipment, gross	$ 1,141	713
Mineral properties
Property, Plant and Equipment [Line Items]
Plant and equipment, gross	50	50
Construction in progress and other
Property, Plant and Equipment [Line Items]
Plant and equipment, gross	$ 35,257	$ 35,287
Minimum | Process equipment
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	5 years
Minimum | Mine equipment
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	5 years
Minimum | Vehicles
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	3 years
Maximum | Process equipment
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	15 years
Maximum | Mine equipment
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	7 years
Maximum | Vehicles
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	5 years