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Note 13 - Subsequent Events (Details Textual) - USD ($) $ in Thousands |  |  |  |  |  |  |  |  |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Mar. 04, 2025 | Feb. 28, 2025 | Feb. 27, 2025 | Feb. 25, 2025 | Jan. 31, 2025 | Jan. 15, 2025 | Jan. 10, 2025 | Jan. 09, 2025 | Jan. 07, 2025 | Jan. 02, 2025 | Feb. 25, 2025 | Jan. 23, 2025 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Proceeds from Issuance of Common Stock |  |  |  |  |  |  |  |  |  |  |  |  | $ 66,353 | $ 65,093 | $ 84,603
The 2023 Equity Distribution Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock Issued During Period, Shares, New Issues (in shares) |  |  |  |  |  |  |  |  |  |  |  |  | 6,300,095 |  |
Proceeds from Issuance of Common Stock |  |  |  |  |  |  |  |  |  |  |  |  | $ 66,400 |  |
Payments of Stock Issuance Costs |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,400 |  |
Subsequent Event [Member] | The 2023 Equity Distribution Agreement [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock Issued During Period, Shares, New Issues (in shares) |  |  |  |  |  |  |  |  |  |  |  | 404,305 |  |  |
Proceeds from Issuance of Common Stock |  |  |  |  |  |  |  |  |  |  |  | $ 3,700 |  |  |
Payments of Stock Issuance Costs |  |  |  |  |  |  |  |  |  |  |  | $ 100 |  |  |
Pivot Bio, Inc. [Member] | Debt Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  |  |  |  |  |  |  |  |  | $ 20,000 |  |  |  |  |
Proceeds from Sale, Maturity and Collection of Investments |  |  |  |  |  |  |  |  | $ 20,000 |  |  |  |  |  |
Hound Labs, Inc. [Member] | Debt Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  |  |  |  |  |  |  | $ 500 |  |  |  |  |  |  |
Investment Owned, Balance, Principal Amount |  |  |  |  |  |  |  | $ 2,900 |  |  |  |  |  |  |
HappyCo, Inc [Member] | Debt Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  |  |  |  |  |  | $ 6,000 |  |  |  |  |  |  |  |
Swift Health Systems Inc. [Member] | Equity Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  |  |  |  |  | $ 2,000 |  |  |  |  |  |  |  |  |
Britecore Holdings, Inc. [Member] | Debt Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  |  |  |  | $ 2,500 |  |  |  |  |  |  |  |  |  |
Better Place Forests Co. [Member] | Debt Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  |  |  |  |  |  |  |  |  |  | $ 400 |  |  |  |
Castle Creek Pharmaceuticals Holdings, Inc. [Member] | Debt Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  |  |  | $ 25,500 |  |  |  |  |  |  |  |  |  |  |
Proceeds from Sale, Maturity and Collection of Investments |  |  |  | $ 16,300 |  |  |  |  |  |  |  |  |  |  |
Long Grove Pharmaceutical, LLC [Member] | Debt Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  |  | $ 10,000 |  |  |  |  |  |  |  |  |  |  |  |
MML US, Inc [Member] | Debt Securities [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments |  | $ 15,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Candesant Biomedical, Inc. [Member] | Debt Securities [Member] | Forecast [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from Sale, Maturity and Collection of Investments | $ 10,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |

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