XML 49 R39.htm IDEA: XBRL DOCUMENT v3.23.1

Note 6 - Fair Value - Significant Level 3 Fair Value Measurement Inputs (Details) - Fair Value, Inputs, Level 3 [Member]		Mar. 31, 2023 USD ($)		Dec. 31, 2022 USD ($)
Investments, fair value		$ 713,407,000		$ 716,319,000
Debt [Member] | Valuation Technique, Discounted Cash Flow [Member]
Investments, fair value		$ 644,854,000		$ 669,617,000
Debt [Member] | Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member] | Hypothetical Market Yield [Member]
Investments, measurement input		0.11		0.03
Debt [Member] | Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member] | Hypothetical Market Yield [Member]
Investments, measurement input		0.20	[1]	0.22
Debt [Member] | Valuation Technique, Discounted Cash Flow [Member] | Weighted Average [Member] | Hypothetical Market Yield [Member]
Investments, measurement input		0.14		0.14	[1]
Debt [Member] | Multiple Probability Weighted Cash Flow Model [Member]
Investments, fair value		$ 39,700,000		$ 16,545,000
Debt [Member] | Multiple Probability Weighted Cash Flow Model [Member] | Minimum [Member] | Probability Weighting [Member]
Investments, measurement input		0.10		0.10
Debt [Member] | Multiple Probability Weighted Cash Flow Model [Member] | Maximum [Member] | Probability Weighting [Member]
Investments, measurement input		1	[1]	0.75
Debt [Member] | Multiple Probability Weighted Cash Flow Model [Member] | Weighted Average [Member] | Probability Weighting [Member]
Investments, measurement input		0.43		0.31	[1]
Debt [Member] | Black-scholes Valuation Model [Member]
Investments, fair value				$ 26,145,000
Debt [Member] | Black-scholes Valuation Model [Member] | Measurement Input, Price Volatility [Member]
Investments, measurement input				0.28
Debt [Member] | Black-scholes Valuation Model [Member] | Measurement Input, Discount for Lack of Marketability [Member]
Investments, measurement input				0.20
Debt [Member] | Black-scholes Valuation Model [Member] | Minimum [Member] | Measurement Input, Share Price [Member]
Investments, measurement input				0.00
Debt [Member] | Black-scholes Valuation Model [Member] | Minimum [Member] | Estimated Time to Exit [Member]
Investments, measurement input				1
Debt [Member] | Black-scholes Valuation Model [Member] | Maximum [Member] | Measurement Input, Share Price [Member]
Investments, measurement input				1.899
Debt [Member] | Black-scholes Valuation Model [Member] | Maximum [Member] | Estimated Time to Exit [Member]
Investments, measurement input				5
Debt [Member] | Black-scholes Valuation Model [Member] | Weighted Average [Member] | Measurement Input, Share Price [Member]
Investments, measurement input	[1]			58.52
Debt [Member] | Black-scholes Valuation Model [Member] | Weighted Average [Member] | Measurement Input, Price Volatility [Member]
Investments, measurement input	[1]			0.28
Debt [Member] | Black-scholes Valuation Model [Member] | Weighted Average [Member] | Measurement Input, Discount for Lack of Marketability [Member]
Investments, measurement input	[1]			0.20
Debt [Member] | Black-scholes Valuation Model [Member] | Weighted Average [Member] | Estimated Time to Exit [Member]
Investments, measurement input	[1]			3
Debt [Member] | Convertible Note Analysis [Member]
Investments, fair value				$ 296,000
Debt [Member] | Convertible Note Analysis [Member] | Measurement Input, Share Price [Member]
Investments, measurement input				168.93
Debt [Member] | Convertible Note Analysis [Member] | Weighted Average [Member] | Measurement Input, Share Price [Member]
Investments, measurement input	[1]			168.93
Warrant [Member] | Black-scholes Valuation Model [Member]
Investments, fair value		$ 24,638,000
Warrant [Member] | Black-scholes Valuation Model [Member] | Measurement Input, Price Volatility [Member]
Investments, measurement input		0.28
Warrant [Member] | Black-scholes Valuation Model [Member] | Measurement Input, Discount for Lack of Marketability [Member]
Investments, measurement input		0.20
Warrant [Member] | Black-scholes Valuation Model [Member] | Minimum [Member] | Measurement Input, Share Price [Member]
Investments, measurement input		0.10
Warrant [Member] | Black-scholes Valuation Model [Member] | Minimum [Member] | Measurement Input, Discount for Lack of Marketability [Member]
Investments, measurement input		0.20
Warrant [Member] | Black-scholes Valuation Model [Member] | Minimum [Member] | Estimated Time to Exit [Member]
Investments, measurement input		1
Warrant [Member] | Black-scholes Valuation Model [Member] | Maximum [Member] | Measurement Input, Share Price [Member]
Investments, measurement input	[1]	1,899
Warrant [Member] | Black-scholes Valuation Model [Member] | Maximum [Member] | Estimated Time to Exit [Member]
Investments, measurement input	[1]	5
Warrant [Member] | Black-scholes Valuation Model [Member] | Weighted Average [Member] | Measurement Input, Share Price [Member]
Investments, measurement input		62.82
Warrant [Member] | Black-scholes Valuation Model [Member] | Weighted Average [Member] | Measurement Input, Price Volatility [Member]
Investments, measurement input		0.28
Warrant [Member] | Black-scholes Valuation Model [Member] | Weighted Average [Member] | Estimated Time to Exit [Member]
Investments, measurement input		3
Other Investments [Member] | Multiple Probability Weighted Cash Flow Model [Member]
Investments, fair value		$ 1,300,000		$ 1,300,000
Other Investments [Member] | Multiple Probability Weighted Cash Flow Model [Member] | Probability Weighting [Member]
Investments, measurement input		1		1
Other Investments [Member] | Multiple Probability Weighted Cash Flow Model [Member] | Measurement Input, Discount Rate [Member]
Investments, measurement input		0.25		0.25
Other Investments [Member] | Multiple Probability Weighted Cash Flow Model [Member] | Weighted Average [Member] | Probability Weighting [Member]
Investments, measurement input		1		1	[1]
Other Investments [Member] | Multiple Probability Weighted Cash Flow Model [Member] | Weighted Average [Member] | Measurement Input, Discount Rate [Member]
Investments, measurement input		0.25		0.25	[1]
Equity Securities [Member] | Last Equity Financing [Member]
Investments, fair value		$ 2,915,000		$ 24.16
Equity Securities [Member] | Last Equity Financing [Member] | Weighted Average [Member] | Measurement Input, Share Price [Member]
Investments, measurement input		40.27		26.93	[1]
[1] Weighted average is calculated by multiplying (a) the unobservable input for each investment in the investment type by (b) (1) the fair value of the related investment in the investment type divided by (2) the total fair value of the investment type.

X

- Definition

Value of input used to measure investment assets.

+ References

No definition available.

+ Details

Name:	hrzn_InvestmentAssetsMeasurementInput
Namespace Prefix:	hrzn_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_DebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_ValuationTechniqueDiscountedCashFlowMember
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:	us-gaap_MeasurementInputTypeAxis=hrzn_HypotheticalMarketYieldMember
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:

X

- Details

Name:	us-gaap_ValuationTechniqueAxis=hrzn_MultipleProbabilityWeightedCashFlowModelMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=hrzn_ProbabilityWeightingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ValuationTechniqueAxis=hrzn_BlackscholesValuationModelMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputPriceVolatilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountForLackOfMarketabilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputSharePriceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=hrzn_EstimatedTimeToExitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ValuationTechniqueAxis=hrzn_ConvertibleNoteAnalysisMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_WarrantMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_OtherInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_ValuationTechniqueAxis=hrzn_LastEquityFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: