Note 9 - Financial Instruments (Details Textual) $ / shares in Units, shares in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Sep. 02, 2016 USD ($) $ / shares shares
(Gain) Loss on Change in Fair Value of Warrant Liability	$ 400,663	$ 117,770	$ (3,525,846)
Warrants and Rights Outstanding	0	$ 6,521,441
The 2016 Warrant [Member]
Class of Warrant or Right Outstanding, Common Stock Value Used to Determine Number of Shares Called				$ 4,000,000.0
Class of Warrant or Right Outstanding, Common Stock Price Per Share Used to Determine Number of Shares Called (in dollars per share) | $ / shares				$ 2.29
Class of Warrant or Right, Subscription Price of Warrants or Rights (in dollars per share) | $ / shares				1.50
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares				$ 1.50
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares		1.0		2.7
Class of Warrant or Right, Exercised During Period (in shares) | shares			0.5
(Gain) Loss on Change in Fair Value of Warrant Liability	$ 400,000
Warrants and Rights Outstanding		$ 6,500,000
The 2016 Warrant [Member] | Measurement Input, Expected Dividend Rate [Member]
Warrants and Rights Outstanding, Measurement Input	0	0
The 2016 Warrant [Member] | Measurement Input, Risk Free Interest Rate [Member]
Warrants and Rights Outstanding, Measurement Input		0.0121
The 2016 Warrant [Member] | Measurement Input, Expected Term [Member]
Warrants and Rights Outstanding, Measurement Input		4.7
The 2016 Warrant [Member] | Measurement Input, Price Volatility [Member]
Warrants and Rights Outstanding, Measurement Input		0.55