Note 8 - Income Taxes - Income Tax Expense (Details) - USD ($)		12 Months Ended
	Dec. 22, 2017	Dec. 31, 2019	Dec. 31, 2018
Income tax benefit at statutory rate		$ (10,019,974)	$ (11,158,530)
Income tax benefit at statutory rate, percentage	35.00%	21.00%	21.00%
State income taxes, net of federal tax benefit		$ (957,616)	$ (1,062,492)
State income taxes, net of federal tax benefit, percentage		2.00%	2.00%
Non-deductible expenses		$ 94,903	$ 6,810
Non-deductible expenses, percentage		(0.20%)
Stock-based compensation		$ 258,338	$ 10,925
Stock-based compensation, percentage		(0.50%)
Non-deductible interest expense			$ 4,074,501
Non-deductible interest expense, percentage			(7.70%)
Derivative and warrant fair value adjustments			$ (63,873)
Derivative and warrant fair value adjustments, percentage			0.10%
Credits		$ (634,842)
Credits, percentage		1.30%
Change in state rate		$ 3,887	$ (2,842)
Change in state rate, percentage
Other		$ 77,009	$ (139,660)
Other, percentage		(0.10%)	0.30%
Change in valuation allowance		$ 11,178,295	$ 8,335,161
Change in valuation allowance, percentage		(23.50%)	(15.70%)
Provision for income taxes		$ 0	$ 0
Provision for income taxes, percentage		0.00%	0.00%