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Revenue - Additional Information (Detail)
12 Months Ended
Dec. 31, 2020
USD ($)
Category
Dec. 31, 2019
USD ($)
Revenue [Line Items]    
Number of categories | Category 3  
Remaining performance obligations $ 0  
Recognized revenue 11,000,000.0 $ 12,700,000
Other Than Maintenance Services [Member]    
Revenue [Line Items]    
Remaining performance obligations $ 17,700,000 $ 13,600,000