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Summary of Significant Accounting Policies (Details) - USD ($) | 3 Months Ended | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Mar. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Mar. 31, 2021 | Nov. 27, 2020 | Sep. 30, 2020 | Aug. 31, 2020 | Dec. 31, 2019
Temporary equity, shares outstanding | 6,000,000 | 6,000,000 | 6,000,000 | 6,000,000 |  |  |  | 6,000,000
Unrecognized tax benefits |  | $ 0 |  |  |  |  |  |
Purchase of aggregate shares |  | 15,000 | 55,000 |  |  |  |  |
SPRING VALLEY ACQUISITION CORP |  |  |  |  |  |  |  |
Unrecognized tax benefits | $ 0 | $ 0 |  |  |  |  |  |
Unrecognized tax benefits accrued for interest and penalties | 0 | $ 0 |  |  |  |  |  |
Accrued Income Taxes, Current | $ 0 |  |  |  |  |  |  |
Class A Common Stock | SPRING VALLEY ACQUISITION CORP |  |  |  |  |  |  |  |
Temporary equity, shares outstanding | 23,000,000 | 23,000,000 |  |  |  |  |  |
Class A Common Stock | SPRING VALLEY ACQUISITION CORP | Private Placement Warrants |  |  |  |  |  |  |  |
Purchase of aggregate shares | 22,529,000 | 22,529,000 |  |  |  |  |  |
Class A Ordinary Shares Subject to Possible Redemption. | SPRING VALLEY ACQUISITION CORP |  |  |  |  |  |  |  |
Temporary equity, shares outstanding |  | 23,000,000 | 23,000,000 |  |  | 23,000,000 | 23,000,000 |
Class A Ordinary Shares Subject to Possible Redemption. | SPRING VALLEY ACQUISITION CORP | Initial Public Offering |  |  |  |  |  |  |  |
Temporary equity, shares outstanding |  | 23,000,000 |  |  | 23,000,000 |  |  |

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