CASH, CASH EQUIVALENTS, AND MARKETABLE SECURITIES - Scheduled contractual maturities of debt securities (Details) $ in Thousands |
Dec. 31, 2020
USD ($)
|
|---|---|
| Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] | |
| Fair Value | $ 132,181 |
| Within 1 Year | 132,181 |
| Commercial paper | |
| Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] | |
| Fair Value | 81,038 |
| Within 1 Year | 81,038 |
| Corporate debt | |
| Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] | |
| Fair Value | 29,915 |
| Within 1 Year | 29,915 |
| Asset-backed | |
| Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] | |
| Fair Value | 12,533 |
| Within 1 Year | 12,533 |
| U.S. agency securities | |
| Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] | |
| Fair Value | 6,995 |
| Within 1 Year | 6,995 |
| U.S. Treasury | |
| Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] | |
| Fair Value | 1,700 |
| Within 1 Year | $ 1,700 |