FAIR VALUE OF MEASUREMENTS AND INVESTMENT SECURITIES - Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Level 1
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	$ 34,999	$ 42,487
Level 1 | Money market funds
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	34,999	42,487
Restricted cash equivalents	1,500	1,500
Level 2
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	0	0
Level 2 | Money market funds
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	0	0
Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	0	0
Level 3 | Money market funds
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total cash equivalents	$ 0	$ 0