Note 11 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Expense (Benefit), Total	$ 0	$ 0
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	21,400,000
Deferred Tax Assets, Valuation Allowance, Total	7,048,088	5,312,769
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	1,800,000	2,200,000
Unrecognized Tax Benefits, Ending Balance	0	0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	0	$ 0
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	$ 67,300,000
Open Tax Year	2014
Domestic Tax Authority [Member] | Earliest Tax Year [Member]
Operating Loss Carryforwards, Expiration Year	2029
Domestic Tax Authority [Member] | Latest Tax Year [Member]
Operating Loss Carryforwards, Expiration Year	2038