Fair value measurements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Fair value Assumptions
Changes in estimates, and other	$ 16,000	$ 44,000
Fair value adjustments to long lived assets	0	$ 0
Fabled Copper Corp. | Sale, not discontinued operations | Binding Letter of Intent Agreement
Fair value Assumptions
Consideration received in shares		200,000
Level 1 | Fabled Copper Corp. | Binding Letter of Intent Agreement
Fair value Assumptions
Investment shares held (in shares)		20,000
Fair Value, Measurements, Recurring
Fair value measurements
Cash and cash equivalents	3,175,000	$ 3,766,000
Short-term investments		11,000
Assets	3,175,000	3,777,000
Fair Value, Measurements, Recurring | Level 1
Fair value measurements
Cash and cash equivalents	3,175,000	3,766,000
Short-term investments		11,000
Assets	$ 3,175,000	$ 3,777,000