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Note 6 - Fair Value (Details Textual) $ / shares in Units, $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2023 USD ($) $ / shares | Sep. 30, 2022 USD ($) | Sep. 30, 2023 USD ($) $ / shares | Sep. 30, 2022 USD ($) | Jun. 30, 2022
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | $ (5,000) | $ (1,117) | $ (5,111) | $ (1,117) |
Unrealized Gain (Loss) on Investments | (17,518) | 3,442 | (24,448) | 1,169 |
Warrant [Member] |  |  |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | 0 | (1,117) | 0 | (1,117) |
Equity Securities [Member] |  |  |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net | 0 | 0 | (111) | 0 |
Fair Value, Inputs, Level 1 [Member] | Debt Securities [Member] |  |  |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 | $ 5,000 |  |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net |  |  | 5,000 |  |
Fair Value, Inputs, Level 1 [Member] | Warrant [Member] |  |  |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 |  | 1,100 |  | 1,100 |
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member] |  |  |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 |  |  | 100 |  |
Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member] |  |  |  |  |
Unrealized Gain (Loss) on Investments |  |  | (33,600) | (3,500) |
Fair Value, Inputs, Level 3 [Member] | Warrant [Member] |  |  |  |  |
Unrealized Gain (Loss) on Investments |  |  | (2,100) | 1,200 |
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member] |  |  |  |  |
Unrealized Gain (Loss) on Investments |  |  | $ (1,600) | (400) |
Fair Value, Inputs, Level 2 [Member] | Warrant [Member] |  |  |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 |  | $ 40 |  | $ 40 |
The 2026 Notes [Member] |  |  |  |  |
Debt Instrument, Share Price (in dollars per share) | $ / shares | $ 23.60 |  | $ 23.60 |  |
The 2026 Notes [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |  |
Debt Instrument, Fair Value Disclosure | $ 54,300 |  | $ 54,300 |  |
The 2027 Notes [Member] |  |  |  |  |
Debt Instrument, Share Price (in dollars per share) | $ / shares | $ 24.18 |  | $ 24.18 |  |
The 2027 Notes [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |  |
Debt Instrument, Fair Value Disclosure | $ 55,600 |  | $ 55,600 |  |
Asset-backed Notes 2019 [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |
Debt Instrument, Fair Value Disclosure | 18,700 |  | 18,700 |  |
Asset-backed Notes 2022 [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |
Debt Instrument, Fair Value Disclosure | $ 100,000 |  | $ 100,000 |  |
Measurement Input, Hypothetical Market Yields [Member] |  |  |  |  |
Debt Instrument, Measurement Input |  |  |  |  | 0.25

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