Note 3 - Financing Agreements (Details Textual) - USD ($)			1 Months Ended	12 Months Ended
	Sep. 08, 2022	Jun. 01, 2021	Jan. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Jul. 28, 2022	Dec. 31, 2020
Proceeds from Issuance or Sale of Equity, Net	$ 7,800,000			$ 7,773,527	$ 31,497,463
Proceeds from Warrant Exercises				$ 18,966	$ 98,481
Proceeds from Issuance or Sale of Equity, Total	8,500,000
Issuance of Equity, Transaction Costs	$ 700,000
Common Stock [Member]
Stock Issued During Period, Shares, New Issues (in shares)				1,976,285	4,133,400
Public Offering [Member]
Number of Units, One, Issued (in shares)		4,133,400
Number of Units, Two, Issued (in shares)		5,066,600
Shares Issued, Price Per Share, One (in dollars per share)		$ 3.75
Shares Issued, Price Per Share, Two (in dollars per share)		$ 3.7499
Proceeds from Issuance or Sale of Equity, Net		$ 31,500,000
Payments of Stock Issuance Costs		$ 3,000,000.0
Public Offering [Member] | Common Stock [Member]
Stock Issued During Period, Shares, New Issues (in shares)		4,133,400
Over-Allotment Option [Member]
Number of Units, One, Issued (in shares)		1,200,000
Registered Direct Offering and Private Placement [Member]
Stock Issued During Period, Shares, New Issues (in shares)	1,976,285
Shares Issued, Price Per Share	$ 2.53
Proceeds from Issuance of Common Stock	$ 5,000,000.0
The Market Offering Agreement "ATM Agreement" [Member] | H.C. Wainwright & Co [Member]
Sale of Stock Agreement, Maximum Aggregate Gross Proceeds			$ 12,900,000
Shares, Issued (in shares)						0
Pre-Funded Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)		1
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 0.0001
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	5,066,600	5,066,600
Class of Warrant or Right, Exercised During Period				4,033,300	1,033,300
Proceeds from Warrant Exercises				$ 403	$ 103
Investor Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)		0.75
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 4.125
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	6,900,000	6,900,000
Class of Warrant or Right, Exercised During Period				6,000	31,800
Proceeds from Warrant Exercises				$ 18,563	$ 98,377
Stock Issued During Period, Shares, Warrant Exercises				4,500
Private Placement Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 2.40
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	3,359,684						556,313
Class of Warrant or Right, Exercised During Period				0
Private Placement Warrants [Member] | Maximum [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	3,359,684
Private Pre-funded Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)	1,383,399
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.0001
Class of Warrant or Right, Exercised During Period				0
Class of Warrant or Right, Purchase Price Per Warrant or Right	$ 2.5299
Proceeds from Issuance of Warrants	$ 3,500,000
Private Pre-funded Warrant [Member] | Maximum [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	1,383,399