Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Risk of concentrations of credit, significant customers and significant suppliers (Details)

v3.21.2
Summary of Significant Accounting Policies - Risk of concentrations of credit, significant customers and significant suppliers (Details) - Customer concentration risk
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Total revenue | Customer          
Concentration Risk [Line Items]          
Concentration risk, percentage 21.20% 20.00% 10.00% 11.00%  
Total revenue | Customer A          
Concentration Risk [Line Items]          
Concentration risk, percentage   20.00%   11.00%  
Total revenue | Customer B          
Concentration Risk [Line Items]          
Concentration risk, percentage 21.20%   10.00%    
Accounts receivable | Customer          
Concentration Risk [Line Items]          
Concentration risk, percentage     16.00%   51.70%
Accounts receivable | Customer B          
Concentration Risk [Line Items]          
Concentration risk, percentage     16.00%    
Accounts receivable | Customer C          
Concentration Risk [Line Items]          
Concentration risk, percentage         28.30%
Accounts receivable | Customer D          
Concentration Risk [Line Items]          
Concentration risk, percentage         23.40%