v3.20.4
Segment and Geographic Information - Summary of Property and Equipment, Net by Geography (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Segment Reporting, Other Significant Reconciling Item [Line Items]      
Property and equipment, net $ 29,541 $ 31,589  
Property, Plant and Equipment [Member]      
Segment Reporting, Other Significant Reconciling Item [Line Items]      
Property and equipment, net $ 29,541 $ 31,589 $ 30,034
Concentration risk, percentage 100.00% 100.00% 100.00%
Property, Plant and Equipment [Member] | United States [Member]      
Segment Reporting, Other Significant Reconciling Item [Line Items]      
Property and equipment, net $ 13,268 $ 15,956 $ 14,168
Concentration risk, percentage 45.00% 51.00% 47.00%
Property, Plant and Equipment [Member] | United Kingdom [Member]      
Segment Reporting, Other Significant Reconciling Item [Line Items]      
Property and equipment, net $ 13,325 $ 12,461 $ 14,446
Concentration risk, percentage 45.00% 39.00% 48.00%
Property, Plant and Equipment [Member] | Rest of world [Member]      
Segment Reporting, Other Significant Reconciling Item [Line Items]      
Property and equipment, net $ 2,948 $ 3,172 $ 1,420
Concentration risk, percentage 10.00% 10.00% 5.00%