| Line Item | Jun 30, 2026 | Mar 31, 2026 | Dec 31, 2025 | Sep 30, 2025 | Jun 30, 2025 | Mar 31, 2025 | Dec 31, 2024 | Sep 30, 2024 | Jun 30, 2024 | Mar 31, 2024 | Dec 31, 2023 | Sep 30, 2023 | Jun 30, 2023 | Mar 31, 2023 | Dec 31, 2022 | Sep 30, 2022 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Operating expense: | ||||||||||||||||
| Exploration, property evaluation and holding costs | ||||||||||||||||
| Corporate administration | ||||||||||||||||
| Depreciation and amortization | ||||||||||||||||
| Total operating expense | ||||||||||||||||
| Non-operating income (loss): | ||||||||||||||||
| Interest income | ||||||||||||||||
| Other loss, net | ||||||||||||||||
| Total non-operating income | ||||||||||||||||
| Loss before income taxes | ||||||||||||||||
| Net loss | ||||||||||||||||
| Net loss per share | ||||||||||||||||
| Net loss per share |