Note 13 - Income Taxes - Reconciliation of Federal Income Tax Attributable to Operations to Income Tax Expense (Benefit) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statutory federal income tax benefit	$ (2,118,000)	$ (9,591,000)
Intangible assets	673,000	3,119,000
Change in valuation allowance	(681,000)	(2,084,000)
Expiration of net operating losses	1,187,000	1,271,000
United States tax reform rate change
Disallowed financing costs	1,119,000	240,000
State and local taxes	(205,000)	2,344,000
Other	25,000	(29,000)
Total income tax benefit	$ 0	$ (4,730,000)