Segment Information - Summary of segment information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Australia segment operating income (expense):
Depreciation and amortization	$ (22)	$ (14)	$ (67)	$ (40)
Corporate administration	(846)	(738)	(2,822)	(2,773)
Gain on grant of royalty interest in mineral titles				16,909
Gain on sale of plant and equipment				802
Total operating income (expense)	(2,105)	(1,833)	(7,448)	12,436
Non-operating income:
Interest income	134	230	443	496
Other income (expense)	1,248	(35)	1,218	(10)
Total non-operating income	1,382	195	1,661	486
Net income (loss)	(723)	(1,638)	(5,787)	12,922
Australia segment long-lived assets	1,940		1,940		$ 1,471
Corporate
Australia segment operating income (expense):
Corporate administration	(846)	(738)	(2,822)	(2,773)
Gain on grant of royalty interest in mineral titles				16,909
Gain on sale of plant and equipment				802
Australia segment | Operating segments
Australia segment operating income (expense):
Employee Compensation	(514)	(500)	(1,614)	(1,324)
2025 feasibility study and related costs	(398)		(1,987)
Drilling and related costs		(646)	(24)	(1,516)
Capitalized development costs		475	150	1,503
Project Programs		(96)	(181)	(279)
Site holding	(123)	(176)	(380)	(355)
Administrative	(127)	(90)	(305)	(273)
Consulting & contract services	(34)	(24)	(98)	(102)
Power	(41)	(24)	(120)	(116)
Depreciation and amortization	(22)	(14)	(67)	(40)
Total operating income (expense)	(1,259)	(1,095)	(4,626)	(2,502)
Non-operating income:
Australia segment expenditures: mineral property and capital assets	336	$ 553	536	$ 1,663
Australia segment long-lived assets	$ 1,871		$ 1,871		$ 1,402