Note 15 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ 11,752,000	$ 11,850,000
Income (Loss) from Continuing Operations before Income Taxes, Foreign	60,000	30,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	284,000	$ 72,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards	123,182,000
Operating Loss Carryforwards, Subject to Expiration	96,250,000
Operating Loss Carryforwards, Not Subject to Expiration	26,931,000
Domestic Tax Authority [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	1,459,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	46,750,000
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	1,618,000
Foreign Tax Authority [Member]
Operating Loss Carryforwards	$ 426,000