Annual report pursuant to Section 13 and 15(d)

Concentration of credit risk and off-balance sheet risk (Details)

v3.20.1
Concentration of credit risk and off-balance sheet risk (Details)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Gross Sales [Member]    
Concentration Risk [Line Items]    
Concentration risk percentage 10.00% 10.00%
Accounts Receivable [Member]    
Concentration Risk [Line Items]    
Concentration risk percentage 44.00% 68.00%