XML 76 R78.htm IDEA: XBRL DOCUMENT v3.20.1
Customer Concentration (Details) - customer
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Customer concentrations | Sales      
Customer Concentration      
Number of customers accounted for more than 10% of sales individually 2 1 3
Concentration risk 35.00% 18.00% 61.00%
Credit concentrations | Accounts receivable      
Customer Concentration      
Number of customers accounted for more than 10% of sales individually 2 1  
Concentration risk 61.00% 43.00%