Annual report pursuant to Section 13 and 15(d)

Leases - Additional Information (Detail)

v3.20.4
Leases - Additional Information (Detail)
12 Months Ended
Feb. 15, 2018
USD ($)
ft²
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Lessee Lease Description [Line Items]        
Rent expenses under operating leases       $ 2,200,000
Build To Suit Lease Arrangement        
Lessee Lease Description [Line Items]        
Ground lease expense       400,000
ASU 2016-02 | Build To Suit Lease Arrangement        
Lessee Lease Description [Line Items]        
Ground lease expense   $ 0 $ 0  
Building | Build To Suit Lease Arrangement        
Lessee Lease Description [Line Items]        
Build-to-suit asset       10,300,000
Capitalized interest costs during the construction period       $ 300,000
South San Francisco California        
Lessee Lease Description [Line Items]        
Lease expiration date   May 31, 2022    
Lease option to extend additional term   5 years    
South San Francisco California | Letter of Credit        
Lessee Lease Description [Line Items]        
Letter of credit maintained   $ 200,000    
Letter of credit renewal term   12 months    
Thousand Oaks California        
Lessee Lease Description [Line Items]        
Lease option to extend additional term   5 years    
Lease agreement area of office, lab and cellular therapy manufacturing space | ft² 90,580      
Lease commencement date Feb. 15, 2018      
Lease initial term 15 years      
Contractual obligations $ 16,400,000      
Lease extension term, option one 10 years      
Lease extension term, option two 9 years      
Thousand Oaks California | Letter of Credit        
Lessee Lease Description [Line Items]        
Letter of credit issued, classified as long-term restricted cash $ 1,200,000      
Thousand Oaks California | Additional Office Space        
Lessee Lease Description [Line Items]        
Lease expiration date   Feb. 28, 2026    
Aurora Colorado        
Lessee Lease Description [Line Items]        
Lease expiration date   Apr. 30, 2024