Note 4 - Other Accrued Liabilities - Other Accrued Liabilities (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Insurance financing	$ 0	$ 591,000
Professional services	472,000	92,000
Operating costs	450,000	539,000
Other	304,000	322,000
Total other accrued liabilities	$ 1,226,000	$ 1,544,000