v3.25.2
Fair Value Measurement - Estimated Fair Value of Financial Instruments Not Carried at Fair Value (Details) - USD ($)
$ in Thousands
Jun. 30, 2025
Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value $ 445,277 $ 316,896
Carrying Value 915,841 751,982
Notes receivable    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value 0 847
Loan commitment assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value 0 21,731
2021 Convertible Note    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value 0 109,838
2025 Convertible Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value 239,251 0
AFG Convertible Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value 75,225 63,033
Equipment financing facility    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value 1,073 2,385
Preferred Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value 532,269 488,696
DOE Loan Facility    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Carrying Value 68,023 65,452
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value 1,009,962 703,213
Level 3 | Notes receivable    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value 0 740
Level 3 | Loan commitment assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value 0 21,051
Level 3 | 2021 Convertible Note    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value 0 91,951
Level 3 | 2025 Convertible Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value 285,000 0
Level 3 | AFG Convertible Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value 77,613 65,053
Level 3 | Equipment financing facility    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value 1,036 2,097
Level 3 | Preferred Stock    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value 575,605 454,581
Level 3 | DOE Loan Facility    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Fair Value $ 70,708 $ 67,740