INCOME TAXES - Deferred taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred Tax Assets
Operating lease liability	$ 282	$ 420
Stock-based compensation	8,131	6,606
License fee	554	594
Net operating loss carryforwards	88,090	79,429
Research and development tax credits	21,397	14,940
Capitalized R&D expense	14,910
Other	1,085	1,352
Total Deferred Tax Assets	134,449	103,341
Valuation Allowance	(134,177)	(102,932)
Net Deferred Tax Assets	272	409
Deferred Tax Liabilities
Right of Use Asset	(272)	(409)
Net Deferred Tax Liabilities	(272)	(409)
Net deferred tax asset (liability)	$ 0	$ 0