Note 2 - Liquidity and Uncertainties (Details Textual) - USD ($)	1 Months Ended		3 Months Ended		12 Months Ended
	Jun. 30, 2020	Apr. 30, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Retained Earnings (Accumulated Deficit), Ending Balance			$ (101,858,826)		$ (100,885,957)
Net Income (Loss) Attributable to Parent, Total			(972,869)	$ (1,600,215)
Cash and Cash Equivalents, at Carrying Value, Ending Balance			16,950,710		14,223,917
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total			2,726,793	$ (750,297)
April 6, 2020 Public Offering [Member]
Proceeds from Issuance of Common Stock		$ 4,600,000	$ 16,900,000
June 30, 2020 Public Offering [Member]
Proceeds from Issuance of Common Stock	$ 13,400,000				$ 2,700,000