Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Mar. 31, 2026	Dec. 31, 2025	Dec. 31, 2022
Investment Plan, Maximum Amount. Approved				$ 20,000
Inventory, Net		$ 364	$ 373
Equipment Constructed for Resale [Member]
Inventory, Net		176	176
Spare Parts [Member]
Inventory, Net		188	197
In Process Equipment [Member]
Inventory, Net		52	$ 53
Minimum [Member]
Debt Securities, Held-to-maturity, Maturity Term (Month)	3 months
Maximum [Member]
Debt Securities, Held-to-maturity, Maturity Term (Month)	36 months
Asset Pledged as Collateral [Member] \| Letter of Credit [Member]
Restricted Cash and Investments		2,798
Asset Pledged as Collateral [Member] \| Letter of Credit [Member] \| Varying Maturity Dates Expiring No Later Than March 31, 2027 [Member]
Restricted Cash and Investments		2,746
Asset Pledged as Collateral [Member] \| Letter of Credit [Member] \| Varying Maturity Dates Expiring No Later Than October 8, 2028 [Member]
Restricted Cash and Investments		$ 52