Quarterly report pursuant to Section 13 or 15(d)

Significant Accounting Policies - Revenue by Major Customers (Detail)

v3.20.4
Significant Accounting Policies - Revenue by Major Customers (Detail) - Revenues - Customer Concentration Risk
3 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Private    
Concentration Risk [Line Items]    
Concentration risk percentage 40.60% 39.40%
Public    
Concentration Risk [Line Items]    
Concentration risk percentage 59.40% 60.60%