Property, Plant and Equipment, Net - Components of plant and equipment, net (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 87,387		$ 86,554
Less, accumulated depreciation and amortization	(33,854)		(31,722)
Total	$ 53,533		54,832
Undivided interest in patent	50.00%
Payments to acquire mineral properties	$ 851	$ 913
Production leach pads
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 11,190		11,190
Test leach pads
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	18 months
Property, plant and equipment, gross	$ 6,241		6,241
Process equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 17,556		17,302
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	10 years
Property, plant and equipment, gross	$ 9,403		9,280
Mine equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,070		4,872
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,700		1,578
Furniture and office equipment
Property, Plant and Equipment [Line Items]
Depreciation Life or Method	7 years
Property, plant and equipment, gross	$ 522		370
Mineral properties(1)
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	50		0
Payments to acquire mineral properties	100
Construction in progress and other
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 35,655		$ 35,721
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