SHARE-BASED COMPENSATION - Stock Option Activity (Details) - $ / shares	3 Months Ended	12 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Stock Option Awards
Beginning balance (in shares)	5,636,154
Granted (in shares)	0
Exercised (in shares)	0
Forfeited (in shares)	0
Ending balance (in shares)	5,636,154	5,636,154
Vested or expect to vest (in shares)	5,636,154
Vested or expect to vest (in shares)	2,876,085
Weighted Average Exercise Price
Beginning balance (in usd per share)	$ 7.68
Granted (in usd per share)	0
Exercised (in usd per share)	0
Forfeited (in usd per share)	0
Ending balance (in usd per share)	7.68	$ 7.68
Vested or expect to vest at end of period (in usd per share)	7.68
Vested or expect to vest at end of period (in usd per share)	$ 7.53
Weighted Average Remaining Contractual Life (Years)
Weighted Average Remaining Contractual Life (Years)	7 years 11 months 26 days	8 years 3 months 14 days
Weighted average remaining contractual life vested or expect to vest	7 years 11 months 26 days
Weighted average remaining contractual life vested or expect to vest	7 years 10 months 17 days

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Gross number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Number of fully vested and expected to vest exercisable options that may be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest exercisable or convertible options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of share options (or share units) exercised during the current period.

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