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FAIR VALUE MEASUREMENTS - Additional Information (Detail) - USD ($)
$ in Millions
2 Months Ended 3 Months Ended 12 Months Ended
Oct. 01, 2018
Nov. 23, 2018
Mar. 31, 2020
Mar. 31, 2018
Dec. 31, 2019
Jul. 20, 2018
Debt Securities, Available-for-sale [Line Items]            
Number of free shares outstanding subject to purchase (in shares)     366,000      
Sangamo France            
Debt Securities, Available-for-sale [Line Items]            
Number of shares acquired (in shares) 13,519,036 11,528,635        
Sangamo France | Share Purchase Agreement and Tender Offer Agreement            
Debt Securities, Available-for-sale [Line Items]            
Number of free shares held by the holders (in shares)           477,000
Estimated fair value liability of free shares         $ 0.2  
Number of shares acquired (in shares)       25,047,671 111,000  
Purchase of additional Sangamo France shares         $ 0.3  
Estimated fair value asset of free shares     $ 0.2