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Note 6 - Fair Value (Details Textual) $ / shares in Units, $ in Thousands | 9 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Sep. 30, 2023 USD ($) | Dec. 31, 2024 USD ($) $ / shares | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) | Jun. 30, 2022
Unrealized Gain (Loss) on Investments |  | $ (18,785) | $ (48,780) | $ (5,552) |
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, 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] | Warrant [Member] |  |  |  |  |
Unrealized Gain (Loss) on Investments |  | (4,300) | (5,300) |  |
Fair Value, Inputs, Level 3 [Member] | Debt Securities [Member] |  |  |  |  |
Unrealized Gain (Loss) on Investments |  | (28,100) | (48,400) |  |
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member] |  |  |  |  |
Unrealized Gain (Loss) on Investments |  | (3,200) | $ (1,600) |  |
Fair Value, Inputs, Level 2 [Member] | Warrant [Member] |  |  |  |  |
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 |  | $ 200 |  |  |
The 2026 Notes [Member] |  |  |  |  |
Debt Instrument, Share Price (in dollars per share) | $ / shares |  | $ 24.85 |  |  |
The 2026 Notes [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |  |
Debt Instrument, Fair Value Disclosure |  | $ 57,200 |  |  |
The 2027 Notes [Member] |  |  |  |  |
Debt Instrument, Share Price (in dollars per share) | $ / shares |  | $ 24.29 |  |  |
The 2027 Notes [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |  |
Debt Instrument, Fair Value Disclosure |  | $ 55,900 |  |  |
The 2031 Convertible Notes [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |
Debt Instrument, Fair Value Disclosure |  | 19,400 |  |  |
Asset-backed Notes 2022 [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |
Debt Instrument, Fair Value Disclosure |  | $ 81,100 |  |  |
Measurement Input, Hypothetical Market Yields [Member] |  |  |  |  |
Debt Instrument, Measurement Input |  |  |  |  | 0.25

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