Note 2 - Significant Accounting Policies 1 (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Retained Earnings (Accumulated Deficit), Total	$ (140,604,000)	$ (128,697,000)
Cash and Cash Equivalents, at Carrying Value, Total	7,363,000	12,872,000
Cash, Uninsured Amount	7,100,000
Accounts Receivable, Allowance for Credit Loss, Current	$ 11,000	22,000
Standard Product Warranty, Term (Year)	2 years
Standard Product Warranty Accrual, Ending Balance	$ 0	$ 0