Quarterly report pursuant to Section 13 or 15(d)

Customer Concentrations - Additional Information (Detail)

v3.20.2
Customer Concentrations - Additional Information (Detail) - Customer Concentration Risk [Member] - Customer
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2020
Sep. 30, 2019
Dec. 31, 2019
Revenues [Member]          
Concentration Risk [Line Items]          
Number of customers 4 3 3 3  
Concentration percentage 81.00% 100.00% 78.00% 55.00%  
Accounts Receivable [Member]          
Concentration Risk [Line Items]          
Number of customers     4   4
Concentration percentage     95.00%   100.00%