Note 9 - Commitments and Contingencies (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2023	Dec. 31, 2022
Payments for Reimbursement of Filtration and Maintenance		$ 22,000	$ 21,000
Notice and Finding of Violation and Order [Member]
Loss Contingency, Damages Sought, Value	$ 230,000