CAPITAL STOCK, STOCK-BASED COMPENSATION AND BENEFIT PLAN - Stock-Based Compensation Expense in Consolidated Statement of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 3,490	$ 6,917	$ 5,979	$ 11,453
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	605	905	1,341	2,094
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	2,685	2,709	4,220	6,056
Restructuring
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 200	$ 3,303	$ 418	$ 3,303