ORGANIZATION, BASIS OF PRESENTATION, AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenues from Strategic Partnering Collaboration Agreements and Research Activity Grants (Detail) - Revenue from contract with customer - Customer concentration risk	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Novartis Institutes for BioMedical Research, Inc.
Concentration Risk [Line Items]
Percentage of revenues	37.00%	34.00%	34.00%	32.00%
Biogen MA, Inc.
Concentration Risk [Line Items]
Percentage of revenues	34.00%	39.00%	37.00%	39.00%
Kite Pharma, Inc.
Concentration Risk [Line Items]
Percentage of revenues	22.00%	23.00%	22.00%	23.00%
Sanofi S.A.
Concentration Risk [Line Items]
Percentage of revenues	6.00%	3.00%	6.00%	4.00%