Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Property, Plant and Equipment, Net
Property, plant and equipment, gross	$ 8,131		$ 8,151
Less: Accumulated depreciation and amortization	(5,373)		(5,362)
Property, plant and equipment, net	2,758		2,789
Depreciation and amortization	23	$ 4
Exploration properties
Property, Plant and Equipment, Net
Property, plant and equipment, gross	2,418		2,418
Royalty properties
Property, Plant and Equipment, Net
Property, plant and equipment, gross	200		200
Buildings
Property, Plant and Equipment, Net
Property, plant and equipment, gross	2,520		2,520
Mining equipment and machinery
Property, Plant and Equipment, Net
Property, plant and equipment, gross	2,069		2,089
Other furniture and equipment
Property, Plant and Equipment, Net
Property, plant and equipment, gross	$ 924		$ 924