ORGANIZATION, BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIIES - Revenues from Strategic Partnering Collaboration Agreements and Research Activity Grants (Details) - Revenue from Contract with Customer - Revenue From Collaboration Agreements, Grants And Licensing Concentration Risk	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Novartis Institutes for BioMedical Research, Inc.
Concentration Risk [Line Items]
Percentage of revenues	36.00%	34.00%	4.00%
Kite Pharma, Inc.
Concentration Risk [Line Items]
Percentage of revenues	35.00%	23.00%	24.00%
Biogen MA, Inc.
Concentration Risk [Line Items]
Percentage of revenues	26.00%	38.00%	24.00%
Sanofi S.A.
Concentration Risk [Line Items]
Percentage of revenues	3.00%	3.00%	5.00%
Pfizer Inc.
Concentration Risk [Line Items]
Percentage of revenues	0.00%	0.00%	40.00%