XML 43 R32.htm IDEA: XBRL DOCUMENT
v3.24.1.u1

Consolidated Schedule of Investments (Unaudited) - Investments (Details) (Parentheticals) | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
NAV % | 214.10% | 218.90%
Investment, Affiliated Issuer, Controlled [Member] |  |
NAV % | 4.10% | 4.40%
Investment, Affiliated Issuer, Controlled [Member] | Consumer-related Technologies [Member] | Debt Securities [Member] |  |
NAV % | 1.50% | 1.60%
Investment, Affiliated Issuer, Controlled [Member] | Life Science [Member] | Other Investments [Member] |  |
NAV % | 1.80% | 1.90%
Investment, Affiliated Issuer, Controlled [Member] | Technology Sector [Member] | Equity Securities [Member] |  |
NAV % | 0.80% | 0.90%
Investment, Affiliated Issuer, Noncontrolled [Member] |  |
NAV % |  | 0.30%
Investment, Affiliated Issuer, Noncontrolled [Member] | Debt Securities [Member] |  |
NAV % | 3.80% |
Investment, Affiliated Issuer, Noncontrolled [Member] | Life Science [Member] | Debt Securities [Member] |  |
NAV % | 3.80% | 0.30%
Investment, Affiliated Issuer, Noncontrolled [Member] | Life Science [Member] | Equity Securities [Member] |  |
NAV % | 0.00% | 0.00%
Investment, Affiliated Issuer, Noncontrolled [Member] | Life Science [Member] | Warrant [Member] |  |
NAV % | 0.00% | 0.00%
Investment, Unaffiliated Issuer [Member] |  |
NAV % | 206.20% | 214.20%
Investment, Unaffiliated Issuer [Member] | Debt Securities [Member] |  |
NAV % | 196.60% | 205.00%
Investment, Unaffiliated Issuer [Member] | Equity Securities [Member] |  |
NAV % | 1.40% | 1.50%
Investment, Unaffiliated Issuer [Member] | Warrant [Member] |  |
NAV % | 7.20% | 7.60%
Investment, Unaffiliated Issuer [Member] | Life Science [Member] | Debt Securities [Member] |  |
NAV % |  | 75.60%
Investment, Unaffiliated Issuer [Member] | Life Science [Member] | Other Investments [Member] |  |
NAV % | 1.00% | 0.10%
Investment, Unaffiliated Issuer [Member] | Life Science [Member] | Debt Investments [Member] |  |
NAV % | 76.80% |
Investment, Unaffiliated Issuer [Member] | Technology Sector [Member] | Debt Securities [Member] |  |
NAV % | 77.60% | 83.30%
Investment, Unaffiliated Issuer [Member] | Technology Sector [Member] | Warrant [Member] |  |
NAV % | 4.60% | 4.50%
Investment, Unaffiliated Issuer [Member] | Healthcare Information and Services Segment [Member] | Debt Securities [Member] |  |
NAV % | 21.00% | 21.50%
Investment, Unaffiliated Issuer [Member] | Healthcare Information and Services Segment [Member] | Warrant [Member] |  |
NAV % | 0.40% | 0.60%
Investment, Unaffiliated Issuer [Member] | Life Science Segment [Member] | Warrant [Member] |  |
NAV % | 2.00% | 2.30%
Investment, Unaffiliated Issuer [Member] | Sustainability Segment [Member] | Debt Securities [Member] |  |
NAV % | 21.20% | 24.60%
Investment, Unaffiliated Issuer [Member] | Sustainability Segment [Member] | Warrant [Member] |  |
NAV % | 0.20% | 0.20%

X
- Definition The NAV percent of investment owned. + References No definition available. + Details
Name: | hrzn_InvestmentOwnedNavPercent
Namespace Prefix: | hrzn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_InvestmentIssuerAffiliationAxis=us-gaap_InvestmentAffiliatedIssuerControlledMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=hrzn_ConsumerrelatedTechnologiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=hrzn_LifeScienceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_OtherInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=us-gaap_TechnologySectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentIssuerAffiliationAxis=us-gaap_InvestmentAffiliatedIssuerNoncontrolledMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_WarrantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentIssuerAffiliationAxis=us-gaap_InvestmentUnaffiliatedIssuerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=hrzn_DebtInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=hrzn_HealthcareInformationAndServicesSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=hrzn_LifeScienceSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EquitySecuritiesByIndustryAxis=hrzn_SustainabilitySegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |