Note 11 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Expense (Benefit), Total	$ 0	$ 0
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	34,100,000
Deferred Tax Assets, Valuation Allowance, Total	10,034,122	7,048,088
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	3,000,000	$ 1,700,000
Unrecognized Tax Benefits, Ending Balance	0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total	0
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	$ 76,400,000
Open Tax Year	2014 2015 2016 2017 2018 2019 2020
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