MAJOR CUSTOMERS, PARTNERSHIPS AND STRATEGIC ALLIANCES - California Institute for Regenerative Medicine (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2018	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues		$ 28,563	$ 57,763	$ 82,715	$ 92,392
Other non-current liabilities		7,631		7,631		$ 7,011
California institute for regenerative medicine agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Funds due under the agreement	$ 8,000
Other non-current liabilities		$ 7,000		7,000		$ 6,400
California institute for regenerative medicine agreement | Research grants
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenues				$ 5,200