Note 15 - Stockholders' Equity (Details Textual) | | | | | | | | | | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | 17 Months Ended | 24 Months Ended | | | | |
Feb. 27, 2024 USD ($) $ / shares shares | Oct. 20, 2023 USD ($) shares | Oct. 04, 2023 $ / shares shares | Sep. 08, 2023 USD ($) shares | Jul. 12, 2023 USD ($) shares | May 15, 2023 USD ($) shares | May 11, 2023 | May 10, 2023 | Jul. 12, 2022 USD ($) $ / shares shares | Nov. 30, 2022 USD ($) $ / shares shares | Nov. 30, 2017 | Nov. 30, 2010 | Sep. 30, 2024 USD ($) $ / shares shares | Mar. 31, 2024 shares | Sep. 30, 2023 USD ($) $ / shares | Jun. 30, 2023 shares | Mar. 31, 2023 shares | Sep. 30, 2024 USD ($) $ / shares shares | Sep. 30, 2023 USD ($) $ / shares | Dec. 31, 2022 USD ($) shares | Dec. 31, 2023 USD ($) $ / shares shares | Jun. 30, 2022 USD ($) $ / shares shares | Sep. 26, 2024 shares | May 24, 2024 USD ($) shares | May 31, 2023 USD ($) $ / shares | Jun. 16, 2020 USD ($) $ / shares shares |
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | | | | | | | | | | | | | $ 0.0001 | | | | | $ 0.0001 | | | $ 0.0001 | | | | | |
Proceeds from Issuance of Common Stock | $ | | | | | | | | | | | | | | | | | | $ 10,000 | $ 1,109,000 | | | | | | | |
Proceeds from Issuance of Private Placement | $ | | | | | | | | | | | | | | | | | | $ 0 | 4,509,000 | | | | | | | |
Common Stock, Capital Shares Reserved for Future Issuance (in shares) | | | | | | | | | | | | | 98,529,412 | | | | | 98,529,412 | | | 18,887,958 | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Payments | $ | | | | | | | | | | | | | $ 0 | | | | | | | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period, Intrinsic Value | $ | | | | | | | | | | | | | $ 0 | | $ 0 | | | $ 0 | $ 0 | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares | | | | | | | | | | | | | $ 0 | | $ 1.9 | | | $ 0.705 | $ 2.82 | | | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested in Period, Fair Value | $ | | | | | | | | | | | | | $ 255,000 | | $ 307,000 | | | $ 892,000 | $ 1,013,000 | | | | | | | |
The 2010 Share Option Plan [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year) | | | | | | | | | | | 10 years | 7 years | | | | | | | | | | | | | | |
Common Stock, Capital Shares Reserved for Future Issuance (in shares) | | | | | | | | | | | | | 28,947 | | | | | 28,947 | | | 28,168 | | | | | |
The 2019 Plan [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Common Stock, Capital Shares Reserved for Future Issuance (in shares) | | | | | | | | | | | | | 279,931 | | | | | 279,931 | | | 71,412 | | | | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares) | | | | | | | | | | | | | 30,000 | | | | | 30,000 | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Increase in Authorized Shares, Percentage of Outstanding Stock Maximum | | | | | | | | | | | | | 4% | | | | | | | | | | | | | |
The 2024 Investor Warrants [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | 817,748 | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | $ 1.34 | | | | | | | | | | | | | | | | | | | | | | | | | |
Voting Preferred Stock [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares | | | | | | | | | | $ 30 | | | | | | | | | | | | | | | | |
Preferred Stock, Convertible, Conversion Ratio | | | | | | | | | | 0.6667 | | | | | | | | | | | | | | | | |
Preferred Stock, Convertible, Volume Weighted Average Price Per Common Share (in dollars per share) | $ / shares | | | | | | | | | | $ 18.75 | | | | | | | | | | | | | | | | |
Senior Preferred Stock [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Preferred Stock, Convertible, Conversion Ratio | | | | | | 2.6667 | | | | | | | | | | | | | | | | | | | | |
Liquidation Preference, Multiplier | | | | | | 2.5 | | | | | | | | | | | | | | | | | | | | |
Conversion Price, Benchmark, Multiplier | | | | | | 2.75 | | | | | | | | | | | | | | | | | | | | |
Series X Convertible Preferred Stock [Member][ | | | | | | | | | | | | | | | | | | | | | | | | | | |
Shares Issued, Price Per Share (in dollars per share) | $ / shares | | | $ 20.1 | | | | | | | | | | | | | | | | | | | | | | | |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | | | $ 0.0001 | | | | | | | | | | | | | | | | | | | | | | | |
Preferred Stock, Convertible, Conversion Ratio | | | 10 | | | | | | | | | | | | | | | | | | | | | | | |
Preferred Stock, Shares Authorized (in shares) | | | 400,000 | | | | | | | | | | | | | | | | | | | | | | | |
Preferred Stock, Dividend Rate, Percentage | | | 12.50% | | | | | | | | | | | | | | | | | | | | | | | |
Series Y Convertible Preferred Stock [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Preferred Stock, Convertible, Conversion Ratio | | | | | | | | | | | | | | | | | | | | | | | | 100 | | |
Preferred Stock, Shares Authorized (in shares) | | | | | | | | | | | | | | | | | | | | | | | 900,000 | 600,000 | | |
Preferred Stock, Convertible, Minimum Proceeds From Conversion | $ | | | | | | | | | | | | | | | | | | | | | | | | $ 30,000,000 | | |
Common Stock [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | | | | | | | | | | 8,333 | | 118,729 | 224,378 | | | | | | | | | |
H.C. Wainwright & Co., LLC [Member] | Placement Agent Warrants [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | 57,242 | | | | | | | | | | | | | | | | | | | | | | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares | $ 1.8313 | | | | | | | | | | | | | | | | | | | | | | | | | |
Equity Purchase Agreement [Member] | Lincoln Park [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Equity Purchase Agreement, Maximum Offering Amount | $ | | | | | | | | | | | | | | | | | | | | | | | | | | $ 31,000,000 |
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | | | | | | | | | | | | | | | | | | | | | | | | | | $ 0.0001 |
Equity Purchase Agreement, Maximum Shares Issuable (in shares) | | | | | | | | | | | | | | | | | | | | | | | | | | 517,560 |
Equity Agreement, Maximum Percentage of Stock Outstanding | | | | | | | | | | | | | | | | | | | | | | | | | | 19.99% |
Equity Agreement, Minimum Average Purchase Price (in dollars per share) | $ / shares | | | | | | | | | | | | | | | | | | | | | | | | | | $ 59.6325 |
Maximum Percentage of Outstanding Stock, Beneficial Ownership | | | | | | | | | | | | | | | | | | | | | | | | | | 9.99% |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | | | | | | | | | | | | | | | | 26,666,000 | | 229,139 | | | | |
Shares Issued, Price Per Share (in dollars per share) | $ / shares | | | | | | | | | | | | | | | | | | | | | | $ 40.5 | | | | |
Stock Issued During Period, Shares, Commitment Fee (in shares) | | | | | | | | | | | | | | | | | | | | | | 13,971 | | | | |
Stock Issued During Period, Value, Commitment Fee | $ | | | | | | | | | | | | | | | | | | | | | | $ 620,000 | | | | |
Deferred Offering Costs | $ | | | | | | | | | | | | | | | | | | | | $ 0 | | $ 123,000 | | | | |
Proceeds from Issuance of Common Stock | $ | | | | | | | | | | | | | | | | | | | | $ 272,000 | | | | | | |
LPC Purchase Agreement 2022 [Member] | Lincoln Park [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Equity Purchase Agreement, Maximum Offering Amount | $ | | | | | | | | | $ 11,000,000 | | | | | | | | | | | | | | | | | |
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | | | | | | | | | $ 0.0001 | | | | | | | | | | | | | | | | | |
Equity Purchase Agreement, Maximum Shares Issuable (in shares) | | | | | | | | | 858,224 | | | | | | | | | | | | | | | | | |
Equity Agreement, Maximum Percentage of Stock Outstanding | | | | | | | | | 19.99% | | | | | | | | | | | | | | | | | |
Maximum Percentage of Outstanding Stock, Beneficial Ownership | | | | | | | | | 9.99% | | | | | | | | | | | | | | | | | |
Shares Issued, Price Per Share (in dollars per share) | $ / shares | | | | | | | | | | | | | $ 1.16 | | | | | $ 1.16 | | | $ 3.966 | | | | | |
Stock Issued During Period, Shares, Commitment Fee (in shares) | | | | | | | | | 45,701 | | | | | | | | | 8,333 | | | 776,452 | | | | | |
Stock Issued During Period, Value, Commitment Fee | $ | | | | | | | | | $ 330,000 | | | | | | | | | $ 10,000 | | | $ 3,080,000 | | | | | |
The 2022 Private Placement [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Issuance of Private Placement | $ | | | | | | | | | | $ 6,720,000 | | | | | | | | | | | | | | | | |
Payments of Stock Issuance Costs | $ | | | | | | | | | | $ 202,000 | | | | | | | | | | | | | | | | |
The 2022 Private Placement [Member] | Convertible Preferred Stock [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | | | | | | 3,185,000 | | | | | | | | | | | | | | | | |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | | | | | | | | | | $ 0.0001 | | | | | | | | | | | | | | | | |
Preferred Stock, Convertible, Shares Issuable (in shares) | | | | | | | | | | 2,123,443 | | | | | | | | | | | | | | | | |
The 2022 Private Placement [Member] | Common Stock [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | | | | | | | | | | $ 0.0001 | | | | | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | | | | | | | | | 116,668 | | | | | | | | | | | | | | | | |
Multi-Tranche Private Placement 2023 [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Equity Purchase Agreement, Maximum Offering Amount | $ | | | | | | | | | | | | | | | | | | | | | | | | | $ 9,000,000 | |
Equity Purchase Agreement, Minimum Aggregate Purchase Amount Per Tranche | $ | | | | | | | | | | | | | | | | | | | | | | | | | $ 500,000 | |
Multi-Tranche Private Placement 2023 [Member] | Senior Preferred Stock [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | | 502,513 | | 292,398 | 500,000 | 280,899 | | | | | | | | | | | | | | | | | | | | |
Preferred Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares | | | | | | | | | | | | | | | | | | | | | | | | | $ 0.0001 | |
Proceeds from Issuance of Preferred Stock and Preference Stock | $ | | $ 2,000,000 | | $ 1,000,000 | $ 2,000,000 | $ 2,000,000 | | | | | | | | | | | | | | | | | | | | |
Registered Direct Offering [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Maximum Percentage of Outstanding Stock, Beneficial Ownership | 4.99% | | | | | | | | | | | | | | | | | | | | | | | | | |
Stock Issued During Period, Shares, New Issues (in shares) | 817,748 | | | | | | | | | | | | | | | | | | | | | | | | | |
Shares Issued, Price Per Share (in dollars per share) | $ / shares | $ 1.465 | | | | | | | | | | | | | | | | | | | | | | | | | |
Proceeds from Issuance or Sale of Equity | $ | $ 1,200,000 | | | | | | | | | | | | | | | | | | | | | | | | | |
Registered Direct Offering [Member] | H.C. Wainwright & Co., LLC [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Placement Agent Fee, Percentage of Gross Proceeds | 7% | | | | | | | | | | | | | | | | | | | | | | | | | |
Management Fee, Percentage of Gross Proceeds | 1% | | | | | | | | | | | | | | | | | | | | | | | | | |
Maximum [Member] | Registered Direct Offering [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Maximum Percentage of Outstanding Stock, Beneficial Ownership | 9.99% | | | | | | | | | | | | | | | | | | | | | | | | | |
Reverse Stock Split [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Stockholders' Equity Note, Stock Split, Conversion Ratio | | | | | | | 15 | | | | | | | | | | | | | | | | | | | |
Reverse Stock Split [Member] | Minimum [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Stockholders' Equity Note, Stock Split, Conversion Ratio | | | | | | | | 5 | | | | | | | | | | | | | | | | | | |
Reverse Stock Split [Member] | Maximum [Member] | | | | | | | | | | | | | | | | | | | | | | | | | | |
Stockholders' Equity Note, Stock Split, Conversion Ratio | | | | | | | | 15 | | | | | | | | | | | | | | | | | | |