CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 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
SPRING VALLEY ACQUISITION CORP
Preference shares, par value, (per share)	$ 0.0001	$ 0.0001		$ 0.0001	$ 0.0001	$ 0.0001
Preference shares, shares authorized	1,000,000	1,000,000		1,000,000	1,000,000	1,000,000
Preference shares, shares issued	0	0		0	0	0
Preference shares, shares outstanding	0	0		0	0	0
Class A Common Stock \| SPRING VALLEY ACQUISITION CORP
Common shares, par value, (per share)	$ 0.0001	$ 0.0001		$ 0.0001	$ 0.0001	$ 0.0001
Common shares, shares authorized	300,000,000	300,000,000		300,000,000	300,000,000	300,000,000
Common shares, shares issued	0	0		0	0	0
Common shares, shares outstanding	0	0		0	0	0
Temporary equity, par value	$ 0.0001	$ 0.0001
Temporary equity, shares outstanding	23,000,000	23,000,000
Temporary Equity, Redemption Price Per Share	$ 10.10	$ 10.10
Class A Ordinary Shares Subject to Possible Redemption. \| SPRING VALLEY ACQUISITION CORP
Temporary equity, shares issued		23,000,000		23,000,000	23,000,000	23,000,000
Temporary equity, par value		$ 0.0001		$ 0.0001	$ 0.0001	$ 0.0001
Temporary equity, shares outstanding		23,000,000		23,000,000	23,000,000	23,000,000
Temporary Equity, Redemption Price Per Share		$ 10.10		$ 10.10	$ 10.10	$ 10.10
Class B ordinary share \| SPRING VALLEY ACQUISITION CORP
Common shares, par value, (per share)	$ 0.0001	$ 0.0001		$ 0.0001	$ 0.0001	$ 0.0001
Common shares, shares authorized	30,000,000	30,000,000		30,000,000	30,000,000	30,000,000
Common shares, shares issued	5,750,000	5,750,000		5,750,000	5,750,000	5,750,000
Common shares, shares outstanding	5,750,000	5,750,000		5,750,000	5,750,000	5,750,000

Face amount or stated value per share of common stock.

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The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws.

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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Per share amount of par value or stated value of stock classified as temporary equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable.

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Amount to be paid per share that is classified as temporary equity by entity upon redemption. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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The number of securities classified as temporary equity that have been sold (or granted) to the entity's shareholders. Securities issued include securities outstanding and securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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