Note 7 - Stockholders' Equity (Details Textual) - USD ($) | Feb. 11, 2021 | Sep. 29, 2020 | Dec. 31, 2021 | Dec. 31, 2020 | Sep. 30, 2021 | Sep. 28, 2021 | Jun. 01, 2021 | Sep. 24, 2020 | Jun. 26, 2020 |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | | | $ 0.01 | $ 0.01 | | | | | |
Proceeds from Issuance or Sale of Equity, Gross | | $ 12,800,000 | | | | | | | |
Proceeds from Issuance or Sale of Equity, Total | | $ 11,200,000 | | | | | | | |
Number of Common Stock Securities Called by Each Unit (in shares) | | 1 | | | | | | | |
Deferred Compensation Liability Conversion to Equity, Amount | | $ 1,500,000 | | $ 1,500,000 | | | | | |
Deferred Compensation Liability Conversion to Equity, Conversion Price (in dollars per share) | | $ 5 | | | | | | | |
Stock Issued During Period, Shares, Cancellation of Accrued Compensation (in shares) | | 300,001 | | 300,001 | | | | | |
Stock Issued During Period, Shares, Conversion of Convertible Securities (in shares) | | 177,626 | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | 1,644,000 | | | | | | | | |
Stock Issued During Period, Value, New Issues | $ 10,300,000 | | $ 9,408,920 | $ 11,158,496 | | | | | |
Proceeds from Issuance of Common Stock | $ 9,400,000 | | | | | | | | |
Proceeds from Warrant Exercises | | | $ 3,404,156 | $ 2,500 | | | | | |
Stock Issued During Period, Shares, Issued for Services (in shares) | | | 13,707 | 26,581 | | | | | |
Conversion of Stock, Shares Issued (in shares) | | | | 716,790 | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent | | | | 110.00% | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year) | | | | 10 years | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) | | | $ 2.87 | $ 1.12 | | | | | |
Prepaid Expense, Value of Stock Issued for Services During Period | | | $ 19,947 | | | | | | |
Expense Related To Consulting And Investment Banking Agreements [Member] | | | | | | | | | |
Share-based Payment Arrangement, Expense | | | 100,560 | $ 45,733 | | | | | |
Share-based Payment Arrangement, Option [Member] | | | | | | | | | |
Share-based Payment Arrangement, Expense | | | 269,427 | $ 18,730 | | | | | |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total | | | $ 1,420,144 | | | | | | |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year) | | | 2 years 2 months 12 days | | | | | | |
Stock Incentive Plan 2020 [Member] | | | | | | | | | |
Common Stock, Capital Shares Reserved for Future Issuance (in shares) | | | | | 1,500,000 | | | | |
Conversion of Series H, Series I, and Series J Preferred Stock into Common Stock [Member] | | | | | | | | | |
Conversion of Stock, Shares Issued (in shares) | | | | 716,790 | | | | | |
Conversion from Convertible Debentures to Conversion Units [Member] | | | | | | | | | |
Debt Conversion, Converted Instrument, Principal and Interest, Amount | | $ 1,214,667 | | | | | | | |
Conversion Warrants [Member] | | | | | | | | | |
Class Of Warrant Or Right, Issued During Period (in shares) | | 2,560,000 | | | | | | | |
Conversion Warrants [Member] | Conversion from Convertible Debentures to Conversion Units [Member] | | | | | | | | | |
Debt Conversion, Converted Instrument, Warrants or Options Issued (in shares) | | 303,668 | | | | | | | |
Unit 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) | | $ 5 | $ 5 | | | | | | |
Warrants and Rights Outstanding, Term (Year) | | 5 years | | | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | 740,034 | | | | | | |
Proceeds from Warrant Exercises, Gross | | | $ 3,700,000 | | | | | | |
Proceeds from Warrant Exercises | | | $ 3,400,000 | | | | | | |
Stock Issued During Period, Shares, Warrants Exercised (in shares) | | | 27,004 | | | | | | |
Pre-Funded Warrants [Member] | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) | | 1 | | | | | | | |
Pre-Funded Warrants [Member] | Conversion from Convertible Debentures to Conversion Units [Member] | | | | | | | | | |
Debt Conversion, Converted Instrument, Warrants or Options Issued (in shares) | | 126,042 | | 126,042 | | | | | |
Management Warrant [Member] | | | | | | | | | |
Number of Warrants Called by Each Unit (in shares) | | 1 | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | 300,001 | | | | | | | |
Stock Purchase Warrants [Member] | | | | | | | | | |
Class of Warrant or Right, Exercised During Period (in shares) | | | 215,672 | 54,557 | | | | | |
Stock Issued During Period, Shares, Warrants Exercised (in shares) | | | 149,705 | 36,902 | | | | | |
June 2020 Warrants [Member] | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | $ 5 | | | | | | | $ 10 |
Warrants and Rights Outstanding, Term (Year) | | | | | | | | | 5 years |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | | | | | 120,000 |
Conversion of Convertible Debenture [Member] | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | 303,668 | | | | | | | |
Unit Warrants [Member] | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | 2,560,000 | | | | | | | |
Unit Warrants [Member] | Conversion from Convertible Debentures to Conversion Units [Member] | | | | | | | | | |
Debt Conversion, Converted Instrument, Warrants or Options Issued (in shares) | | | | 303,668 | | | | | |
Representative Warrants 2020 [Member] | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | $ 5.50 | | | | | $ 5.50 | |
Warrants and Rights Outstanding, Term (Year) | | 42 months | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | 128,000 | | | | | | | |
Representative Warrants 2021 [Member] | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ 6.875 | | 6.875 | | | | | | |
Warrants and Rights Outstanding, Term (Year) | 42 months | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | 72,000 | | | | | | | | |
Warrants 2021 [Member] | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | | | $ 13 | | | $ 13 | | | |
Warrants and Rights Outstanding, Term (Year) | | | | | | 5 years | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | | | | | | 100,000 | | | |
Series B Convertible Preferred Stock [Member] | | | | | | | | | |
Preferred Stock, Shares Outstanding, Ending Balance (in shares) | | | 0 | 100 | | | 100 | | |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | | | $ 1,000 | $ 1,000 | | | | | |
Capital Units Tranche One [Member] | Capital Units [Member] | | | | | | | | | |
Number of Common Stock Securities Called by Each Unit (in shares) | | 1 | | | | | | | |