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Fair Value Measurements - Changes in the fair value of the derivative warrant liabilities (Details) - Level 3 - SPRING VALLEY ACQUISITION CORP - USD ($) | 3 Months Ended | 4 Months Ended | 12 Months Ended
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Mar. 31, 2022 | Dec. 31, 2020 | Dec. 31, 2021
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |
Derivative warrant liabilities at the beginning | $ 14,774,000 | $ 0 | $ 14,685,000
Issuance of Public and Private Warrants |  | 22,529,000 |
Transfer of Public Warrants to Level 2 | (14,774,000) | (12,650,000) |
Change in fair value of derivative warrant liabilities |  | 4,806,000 | 89,000
Derivative warrant liabilities at the end | $ 0 | $ 14,685,000 | $ 14,774,000

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- Definition Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of issuances of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258 + Details
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- Definition Amount of transfers of financial instrument classified as a liability into (out of) level 3 of the fair value hierarchy. + References No definition available. + Details
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