INCOME TAXES - Schedule of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets (liabilities):
Net operating loss carryforwards	$ 52,568	$ 24,059
Research and development tax credits	5,439	2,477
Operating lease liabilities	7,172	2,147
Accruals and other	1,251	680
Stock-based compensation	3,835	1,434
Total deferred tax assets	70,265	30,797
Valuation Allowance	(63,014)	(28,709)
Subtotal	7,251	2,088
Right-of-use assets	(7,236)	(2,063)
Net fixed assets	(15)	(25)
Net deferred tax assets	$ 0	$ 0