DEBT OBLIGATIONS - Interest Expense, Net (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Dec. 31, 2025 |
|
| Debt Instrument [Line Items] | |||||
| Amortization of debt discount and debt issuance costs | $ 3,621 | $ 2,074 | |||
| Other interest cost | $ 2,507 | $ 362 | 4,611 | 516 | |
| Interest capitalized to property, plant and equipment, net | (2,933) | (2,502) | (5,422) | (2,587) | |
| Interest expense, net | 9,703 | 5,414 | 19,549 | 13,029 | |
| Interest Payable | 11,000 | 11,000 | $ 10,900 | ||
| Convertible Debt | |||||
| Debt Instrument [Line Items] | |||||
| Coupon interest | 6,471 | 6,513 | 12,984 | 13,026 | |
| Amortization of debt issuance costs | 987 | 1,041 | 2,054 | 2,074 | |
| Interest Expense, Debt | 7,458 | 7,554 | 15,038 | 15,100 | |
| Notes Payable, Other Payables | Samarium Project Loan | |||||
| Debt Instrument [Line Items] | |||||
| Coupon interest | 2,017 | 0 | 4,035 | 0 | |
| Amortization of debt discount and debt issuance costs | 654 | 0 | 1,287 | 0 | |
| Interest Expense, Debt | $ 2,671 | $ 0 | $ 5,322 | $ 0 | |
| X | ||||||||||
- Definition Amount of amortization expense attributable to debt issuance costs. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of amortization expense attributable to debt discount (premium) and debt issuance costs. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of interest capitalized during the period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of the cost of borrowed funds accounted for as interest expense for debt. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Amount of interest expense classified as nonoperating. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of interest expense classified as other. No definition available.
|
| X | ||||||||||
- Definition Amount of interest payable on debt, including, but not limited to, trade payables. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|