FAIR VALUE MEASUREMENTS - Activity Measured on a Recurring Basis (Details) - Non-employee Earnouts - USD ($) $ in Thousands |
3 Months Ended | 12 Months Ended |
|---|---|---|
Mar. 31, 2022 |
Dec. 31, 2021 |
|
| Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] | ||
| Beginning Balance | $ 21,466 | $ 0 |
| Initial valuation of the Non-employee Earnout liability | 68,412 | |
| Mark-to-market (gain) on Non-employee Earnout liability | 5,879 | (46,946) |
| Ending Balance | $ 27,345 | $ 21,466 |