INCOME TAXES - Tax credit carryforward (Details) $ in Millions |
Dec. 31, 2021
USD ($)
|
|---|---|
| Research tax credit carryforward | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit carryforward | $ 4.8 |
| Orphan drug credit carryforward | |
| Tax Credit Carryforward [Line Items] | |
| Tax credit carryforward | $ 10.2 |