Note 13 - Income Taxes - Components of Company's Deferred Tax Assets and Liabilities for Federal and State Income Taxes (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 26,758,000	$ 27,312,000
Income tax credit carryforwards	2,757,000	2,769,000
Stock compensation	384,000	850,000
Lease Obligation	185,000
Deferred Revenue	419,000
Other	943,000	1,027,000
Total deferred tax assets	31,446,000	31,958,000
Deferred tax liabilities
Indefinite lived intangible assets
Depreciation and amortization	(408,000)	(419,000)
Lease asset	(180,000)
Total deferred tax liabilities	(588,000)	(419,000)
Valuation allowance	(30,858,000)	(31,539,000)
Net deferred taxes