Note 6 - Stockholders' Equity (Details Textual) | | | 1 Months Ended | 3 Months Ended | 6 Months Ended | |
May 21, 2024 USD ($) $ / shares shares | Jan. 16, 2024 shares | Jun. 30, 2024 USD ($) $ / shares shares | Jan. 31, 2024 shares | Mar. 31, 2024 shares | Jun. 30, 2024 USD ($) $ / shares shares | Jun. 30, 2023 USD ($) | Dec. 31, 2023 shares |
Common Stock, Shares Authorized (in shares) | | 150,000,000 | 150,000,000 | | | 150,000,000 | | 600,000,000 |
Proceeds from Warrant Exercises | $ | | | | | | $ 1,389,363 | $ 0 | |
Stock Issued During Period, Shares, Issued for Services (in shares) | | | | 6,703 | | | | |
Stock Issued During Period, Shares, Reverse Stock Splits (in shares) | | | | 55,422 | | | | |
Stock Incentive Plan 2020 [Member] | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period | | | | | | 961 | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number | | | 133,648 | | | 133,648 | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price | $ / shares | | | $ 28.39 | | | $ 28.39 | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | | | | | | 7 years 8 months 12 days | | |
Common Stock, Capital Shares Reserved for Future Issuance | | | 333,648 | | | 333,648 | | |
May 2024 Pre-funded Warrants [Member] | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | 582,844 | | | | | | | |
Stock Issued During Period, Shares, Warrant Exercise (in shares) | | | 582,844 | | | | | |
May 2024 Common Warrants [Member] | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | $ 1.68 | | | | | | | |
May 2024 Common Warrants [Member] | Maximum [Member] | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | 1,605,688 | | | | | | | |
December 2023 Pre-funded Warrants [Member] | | | | | | | | |
Stock Issued During Period, Shares, Warrant Exercise (in shares) | | | 238,000 | | 269,032 | | | |
Warrants Issued in June 2020 [Member] | | | | | | | | |
Stock Issued During Period, Shares, Warrant Cashless Exercise (in shares) | | | 2,549 | | | | | |
Class of Warrant or Right, Warrants Exercised (in shares) | | | 4,000 | | | | | |
Warrants Issued in December 2023 [Member] | | | | | | | | |
Stock Issued During Period, Shares, Warrant Exercise (in shares) | | | 826,998 | | | | | |
Proceeds from Warrant Exercises | $ | | | $ 1,400,000 | | | | | |
Registered Direct Offering [Member] | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | 220,000 | | | | | | | |
May 2024 Offering [Member] | | | | | | | | |
Proceeds from Issuance or Sale of Equity | $ | $ 1,200,000 | | | | | | | |
Reverse Stock Split [Member] | | | | | | | | |
Stockholders' Equity Note, Stock Split, Conversion Ratio | | 15 | | | | | | |