SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - STOCK BASED COMPENSATION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Stock-Based Compensation Expense
Stock-based compensation expense included in operating expenses	$ 7,204	$ 2,063	$ 14,110	$ 5,813
Stock Options
Stock-Based Compensation Expense
Stock-based compensation expense included in operating expenses	3,200		3,200
Research and development
Stock-Based Compensation Expense
Stock-based compensation expense included in operating expenses	2,951	932	5,847	2,799
General and administrative
Stock-Based Compensation Expense
Stock-based compensation expense included in operating expenses	$ 4,253	$ 1,131	$ 8,263	$ 3,014