XML 66 R50.htm IDEA: XBRL DOCUMENT
v3.26.1

Note 7 - Borrowings (Details Textual) $ / shares in Units, $ in Thousands |  |  |  |  |  |  |  |  |  |  |  | 3 Months Ended | 6 Months Ended | 12 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 26, 2026 | Feb. 26, 2026 | Jan. 28, 2026 USD ($) | Sep. 04, 2025 USD ($) | May 23, 2025 USD ($) | Apr. 25, 2025 | Apr. 17, 2025 | Oct. 17, 2024 USD ($) | Jun. 21, 2024 USD ($) | Jun. 19, 2024 | May 24, 2023 USD ($) | Jun. 30, 2026 USD ($) $ / shares | Jun. 30, 2025 USD ($) $ / shares shares | Jun. 30, 2026 USD ($) $ / shares shares | Jun. 30, 2025 USD ($) $ / shares shares | Dec. 31, 2025 USD ($) $ / shares | Dec. 15, 2025 USD ($) | Dec. 31, 2024 $ / shares | Jun. 29, 2023 USD ($) | Jun. 15, 2022 USD ($) $ / shares | Mar. 30, 2021 USD ($) $ / shares | Apr. 21, 2020 USD ($)
Asset Coverage to Borrowings, Ratio, Percent |  |  |  |  |  |  |  |  |  |  |  | 0.00% |  |  |  |  |  |  |  |  |  |
Restricted Investments |  |  |  |  |  |  |  |  |  |  |  | $ 2,675 |  | $ 2,675 |  | $ 2,463 |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  | 734,200 |  | 734,200 |  | $ 806,750 |  |  |  |  |  |
Gain (Loss) on Extinguishment of Debt |  |  |  |  |  |  |  |  |  |  |  | $ 0 | $ (776) | $ (1,432) | $ (776) |  |  |  |  |  |  |
Share Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  | $ 4.73 | $ 7.2 | $ 4.73 | $ 7.2 | $ 6.45 |  | $ 8.99 |  |  |  |
Debt Conversion, Original Debt, Amount |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 15,050 | $ 12,500 |  |  |  |  |  |  |
Key Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Current Borrowing Capacity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 150,000 |  |  |  |  |  |
Conversion of 2030 Notes Into Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Original Debt, Amount |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 15,100 |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued (in shares) | shares |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,118,250 |  |  |  |  |  |  |  |
Debt Instrument, Convertible, Weighted Average Conversion Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 7.12 |  |  |  |  |  |  |  |
Debt Instrument, Convertible, Accelerated Unamortized Debt Issuance Costs |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,300 |  |  |  |  |  |  |  |
Conversion of 2031 Notes Into Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Original Debt, Amount |  |  |  |  |  |  |  |  |  |  |  |  | $ 12,500 |  | $ 12,500 |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued (in shares) | shares |  |  |  |  |  |  |  |  |  |  |  |  | 1,621,503 |  | 1,621,503 |  |  |  |  |  |  |
Debt Instrument, Convertible, Weighted Average Conversion Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  | $ 7.79 |  | $ 7.79 |  |  |  |  |  |  |
Debt Instrument, Convertible, Accelerated Unamortized Debt Issuance Costs |  |  |  |  |  |  |  |  |  |  |  |  | $ 800 |  | $ 800 |  |  |  |  |  |  |
Key Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity, Accordian Feature |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 150,000 |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 300,000 |  |  |
Line of Credit Facility, Advance Rate of Eligible Debt Investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 60.00% |  |  |
Long-Term Debt, Weighted Average Interest Rate, over Time |  |  |  |  |  |  |  |  |  |  |  | 6.85% | 7.60% | 6.85% | 7.60% |  |  |  |  |  |  |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.75% |  |  |  |  |  |  |  |
Line of Credit Facility, Current Borrowing Capacity |  |  |  |  |  |  |  |  |  |  |  | $ 150,000 |  | $ 150,000 |  |  |  |  |  |  |  |
Line of Credit Facility, Remaining Borrowing Capacity |  |  |  |  |  |  |  |  |  |  |  | 82,700 |  | 82,700 |  | 49,600 |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  | $ 150,000 |  | $ 150,000 |  | $ 150,000 |  |  |  |  |  |
Key Facility [Member] | Prime Rate [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  | 0.10% |  |  |  |  |  |  |  | 0.25% |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Variable Rate |  |  |  |  |  |  |  |  |  |  |  | 6.75% |  | 6.75% |  | 6.75% |  |  |  |  |  |
NYL Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  |  |  |  |  |  |  |  |  | $ 250,000 |  |  |  |  |  |  |  |  |  |  | $ 100,000
Line of Credit Facility, Current Borrowing Capacity |  |  |  |  |  |  |  |  |  |  |  | $ 69,000 |  | $ 69,000 |  | $ 69,000 |  |  |  |  |  |
Line of Credit Facility, Remaining Borrowing Capacity |  |  |  |  |  |  |  |  |  |  |  | 7,900 |  | 7,900 |  | 1,900 |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity, Accordion Feature |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 200,000
Line of Credit Facility, Advance Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 67.00%
Line of Credit Facility, Change in Maximum Borrowing Capacity |  |  |  |  |  |  |  |  |  |  | $ 50,000 |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  |  |  |  |  |  | 4.60% |  |  |  |  |  |  |  |  |  |  |
Long-Term Line of Credit |  |  |  |  |  |  |  |  |  |  |  | $ 181,000 |  | $ 181,000 |  | $ 181,000 |  |  |  |  |  |
Line of Credit Facility, Interest Rate at Period End |  |  |  |  |  |  |  |  |  |  |  | 6.61% |  | 6.61% |  | 6.55% |  |  |  |  |  |
Restricted Investments |  |  |  |  |  |  |  |  |  |  |  | $ 1,400 |  | $ 1,400 |  | $ 1,400 |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  | 250,000 |  | 250,000 |  | 250,000 |  |  |  |  |  |
NYL Facility [Member] | Three Year I Curve [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  | 2.95% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Nuveen Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity, Accordian Feature |  |  |  |  |  |  |  |  | $ 200,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Maximum Borrowing Capacity |  |  |  |  | $ 200,000 |  |  |  | $ 100,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Current Borrowing Capacity |  |  |  |  |  |  |  |  |  |  |  | 110,000 |  | 110,000 |  | 110,000 |  |  |  |  |  |
Line of Credit Facility, Remaining Borrowing Capacity |  |  |  |  |  |  |  |  |  |  |  | 26,700 |  | 26,700 |  | 12,100 |  |  |  |  |  |
Line of Credit Facility, Advance Rate |  |  |  |  |  |  |  |  | 67.50% |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Change in Maximum Borrowing Capacity |  |  |  |  | $ 100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-Term Line of Credit |  |  |  |  |  |  |  |  |  |  |  | $ 90,000 |  | $ 90,000 |  | $ 90,000 |  |  |  |  |  |
Line of Credit Facility, Interest Rate at Period End |  |  |  |  |  |  |  |  |  |  |  | 7.21% |  | 7.21% |  | 7.21% |  |  |  |  |  |
Restricted Investments |  |  |  |  |  |  |  |  |  |  |  | $ 1,300 |  | $ 1,300 |  | $ 1,100 |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  | 200,000 |  | 200,000 |  | 200,000 |  |  |  |  |  |
Nuveen Facility [Member] | Selected Interest Rates (Daily) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  | 2.95% |  |  |  | 3.15% |  |  |  |  |  |  |  |  |  |  |  |  |
The 2026 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.875% |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  | 0 |  | 0 |  | 57,500 |  |  |  |  | $ 57,500 |
Gain (Loss) on Extinguishment of Debt |  |  | $ 100 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
The 2026 Notes Underwriter Option [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 7,500 |
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 25 |
The 2027 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6.25% |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  | 57,500 |  | 57,500 |  | 57,500 |  |  |  | $ 50,000 |  |
The 2027 Notes Underwriter Option [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 7,500 |  |
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 25 |  |
The 2028 Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7.00% |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  |  |  |  |  | $ 57,500 |  | $ 57,500 |  | $ 57,500 | $ 57,500 |  |  |  |  |
Debt Instrument, Redemption Price, Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |
The 2028 Notes [Member] | Treasury Rate [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.50% |  |  |  |  |  |
The 2030 Convertible Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  | 5.50% |  |  |  |  |  |  |  | 5.50% |  | 5.50% |  |  |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  | $ 40,000 |  |  |  |  |  |  |  | $ 16,450 |  | $ 16,450 |  | $ 31,500 |  |  |  |  |  |
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  | $ 6.98 |  | $ 6.98 |  |  |  |  |  |  |  |
Debt Instrument, Redemption Price, Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |
Proceeds from Convertible Debt |  |  |  | $ 36,600 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Maturity Date |  |  |  | Sep. 04, 2030 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Convertible, Threshold Consecutive Trading Days |  |  |  |  |  |  |  |  |  |  |  |  | 5 | 5 | 5 |  |  |  |  |  |  |
Debt Instrument, Convertible, Number of Equity Instruments |  |  |  |  |  |  |  |  |  |  |  |  |  | 2,356,734 |  |  |  |  |  |  |  |
Share Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  | $ 4.73 |  | $ 4.73 |  |  |  |  |  |  |  |
Debt Instrument, Convertible, Maximum Beneficial Ownership Percentage |  |  |  |  |  |  |  |  |  |  |  |  |  | 4.99% |  |  |  |  |  |  |  |
Convertible Debt |  |  |  |  |  |  |  |  |  |  |  | $ 16,500 | $ 0 | $ 16,500 | $ 0 | 31,500 |  |  |  |  |  |
The 2031 Convertible Notes [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  |  |  |  | 7.125% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Face Amount |  |  |  |  |  |  |  | $ 20,000 |  |  |  | $ 2,750 |  | $ 2,750 |  | 2,750 |  |  |  |  |  |
Debt Instrument, Convertible, Conversion Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  | $ 6.98 |  | $ 6.98 |  |  |  |  |  |  |  |
Debt Instrument, Redemption Price, Percentage |  |  |  |  |  |  | 100.00% | 100.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from Convertible Debt |  |  |  |  |  |  |  | $ 18,600 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Maturity Date |  |  |  |  |  |  |  | Oct. 17, 2031 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Convertible, Threshold Consecutive Trading Days |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 |  |  |  |  |  |  |  |
Debt Instrument, Convertible, Number of Equity Instruments |  |  |  |  |  |  |  |  |  |  |  |  |  | 393,983 |  |  |  |  |  |  |  |
Share Price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  |  | $ 4.73 |  | $ 4.73 |  |  |  |  |  |  |  |
Debt Instrument, Convertible, Maximum Beneficial Ownership Percentage |  |  |  |  |  |  |  | 4.99% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Convertible Debt |  |  |  |  |  |  |  |  |  |  |  | $ 2,800 |  | $ 2,800 |  | $ 2,800 |  |  |  |  |  |
Debt Instrument, Interest Rate, Increase From Failure to Maintain Investment Rating |  |  |  |  |  |  |  | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Increase From Default |  |  |  |  |  |  |  | 2.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Asset Coverage to Borrowings, Ratio, Percent |  |  |  |  |  |  |  |  |  |  |  | 150.00% |  |  |  |  |  |  |  |  |  |
Minimum [Member] | Key Facility [Member] | Prime Rate [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 4.10% |  |  |  |  |  |  |  |  | 4.25% |  |  |  |  |  |  |  |  |  |  |  |
Minimum [Member] | Nuveen Facility [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  | 5.00% |  |  |  | 5.00% |  |  |  |  |  |  |  |  |  |  |  |  |
Minimum [Member] | Nuveen Facility [Member] | Selected Interest Rates (Daily) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate, Treasury Yield Maturity (Year) |  |  |  |  |  |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum [Member] | Nuveen Facility [Member] | Selected Interest Rates (Daily) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate, Treasury Yield Maturity (Year) |  |  |  |  |  |  |  |  | 5 years |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted Average [Member] | Nuveen Facility [Member] | Selected Interest Rates (Daily) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate, Treasury Yield Maturity (Year) |  |  |  |  |  |  |  |  | 4 years 10 months 17 days |  |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition The asset coverage to borrowings ratio percentage. + References No definition available. + Details
Name: | hrzn_AssetCoverageToBorrowingsRatioPercent
Namespace Prefix: | hrzn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of maturity for treasury yield used to calculate basis spread on variable rate of debt instrument. + References No definition available. + Details
Name: | hrzn_DebtInstrumentBasisSpreadOnVariableRateTreasuryYieldMaturity
Namespace Prefix: | hrzn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The accelerated unamortized debt issuance costs for convertible debt instruments. + References No definition available. + Details
Name: | hrzn_DebtInstrumentConvertibleAcceleratedUnamortizedDebtIssuanceCosts
Namespace Prefix: | hrzn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Information pertaining to the agreement. + References No definition available. + Details
Name: | hrzn_DebtInstrumentConvertibleMaximumBeneficialOwnershipPercentage
Namespace Prefix: | hrzn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The weighted average conversion price for convertible debt instruments. + References No definition available. + Details
Name: | hrzn_DebtInstrumentConvertibleWeightedAverageConversionPrice
Namespace Prefix: | hrzn_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Pertains to the term of the agreement. + References No definition available. + Details
Name: | hrzn_DebtInstrumentInterestRateIncreaseFromDefault
Namespace Prefix: | hrzn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Pertains to the term of the agreement. + References No definition available. + Details
Name: | hrzn_DebtInstrumentInterestRateIncreaseFromFailureToMaintainInvestmentRating
Namespace Prefix: | hrzn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The variable rate of debt instrument. + References No definition available. + Details
Name: | hrzn_DebtInstrumentVariableRate
Namespace Prefix: | hrzn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The advance rate under line of credit facility. + References No definition available. + Details
Name: | hrzn_LineOfCreditFacilityAdvanceRate
Namespace Prefix: | hrzn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The advance rate of eligible debt investments under line of credit facility. + References No definition available. + Details
Name: | hrzn_LineOfCreditFacilityAdvanceRateOfEligibleDebtInvestments
Namespace Prefix: | hrzn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The change in maximum borrowing capacity in line of credit facility. + References No definition available. + Details
Name: | hrzn_LineOfCreditFacilityChangeInMaximumBorrowingCapacity
Namespace Prefix: | hrzn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Maximum borrowing capacity under the credit facility after the accordion feature increase. + References No definition available. + Details
Name: | hrzn_LineOfCreditFacilityMaximumBorrowingCapacityAccordianFeature
Namespace Prefix: | hrzn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The accordion feature for the maximum borrowing capacity under line of credit facility. + References No definition available. + Details
Name: | hrzn_LineOfCreditFacilityMaximumBorrowingCapacityAccordionFeature
Namespace Prefix: | hrzn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_ConvertibleDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482913/230-10-50-3 + Details
Name: | us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482913/230-10-50-3 + Details
Name: | us-gaap_DebtConversionOriginalDebtAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The price per share of the conversion feature embedded in the debt instrument. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-5 + Details
Name: | us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of equity instruments that the holder of the debt instrument would receive if the debt was converted to equity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-3 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-6 Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-7 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B + Details
Name: | us-gaap_DebtInstrumentConvertibleNumberOfEquityInstruments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentConvertibleThresholdConsecutiveTradingDays1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482949/835-30-55-8 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69B -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 69C -Publisher FASB -URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482900/835-30-50-1 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 835 -SubTopic 30 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482925/835-30-45-2 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Date when the debt instrument is scheduled to be fully repaid, in YYYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 8: http://www.xbrl.org/2003/role/exampleRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B + Details
Name: | us-gaap_DebtInstrumentMaturityDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage price of original principal amount of debt at which debt can be redeemed by the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 470 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477734/942-470-50-3 + Details
Name: | us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481303/470-50-40-2 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 470 -SubTopic 50 -Section 40 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481303/470-50-40-4 + Details
Name: | us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-9 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_LineOfCredit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-8 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The effective interest rate at the end of the reporting period. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-8 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-8 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)(3)(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480657/210-10-S50-8 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481544/470-10-50-6 + Details
Name: | us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average interest rate of long-term debt outstanding calculated over time. + References No definition available. + Details
Name: | us-gaap_LongTermDebtWeightedAverageInterestRateOverTime
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow from the issuance of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-14 + Details
Name: | us-gaap_ProceedsFromConvertibleDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Investments which are not defined as or included in marketable (debt, equity, or other) securities whose use is restricted in whole or in part, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 954 -SubTopic 210 -Name Accounting Standards Codification -Section 45 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477220/954-210-45-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 954 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478600/954-210-50-2 + Details
Name: | us-gaap_RestrictedInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Price of a single share of a number of saleable stocks of a company. + References No definition available. + Details
Name: | us-gaap_SharePrice
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DebtConversionByUniqueDescriptionAxis=hrzn_KeyFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtConversionByUniqueDescriptionAxis=hrzn_ConversionOf2030NotesIntoCommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtConversionByUniqueDescriptionAxis=hrzn_ConversionOf2031NotesIntoCommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_KeyFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_NYLFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=hrzn_ThreeYearICurveMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_NuveenFacilityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=hrzn_SelectedInterestRatesDailyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_The2026NotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_The2026NotesUnderwriterOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_The2027NotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_The2027NotesUnderwriterOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_The2028NotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=hrzn_TreasuryRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_The2030ConvertibleNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=hrzn_The2031ConvertibleNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_WeightedAverageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |