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Note 1 - Organization (Details Textual) | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Investment Owned, Net Assets, Percentage | 219.40% | 207.60%
Investment, Affiliated Issuer, Controlled [Member] |  |
Investment Owned, Net Assets, Percentage | 3.70% | 9.50%
Investment, Affiliated Issuer, Controlled [Member] | HIMV LLC [Member] | Co-lender [Member] |  |
Subsidiary, Ownership Percentage, Noncontrolling Owner | 30.00% |
Investment, Affiliated Issuer, Controlled [Member] | HIMV LLC [Member] | Co-lender [Member] |  |
Investment Owned, Net Assets, Percentage | 30.00% |
Investment, Affiliated Issuer, Controlled [Member] | HIMV LLC [Member] | Horizon Technology Finance Corporation [Member] |  |
Investment Owned, Net Assets, Percentage | 70.00% |

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