Note 13. Concentration of Credit Risk

The following represents customers that accounted for 10% or more of total revenue during the three and nine months ended September 30, 2019 and 2018, and customers that accounted for 10% or more of total trade accounts receivable at September 30, 2019 and 2018.

Net revenue by geographic area are as follows. Revenue is attributed by geographic location based on the bill-to location of the Company’s customers.

Although the Company ships the majority of antennas to its customers in China (primarily Original Design Manufacturers and distributors), the end-users of the Company’s products are much more geographically diverse.

During the three and nine months ended September 30, 2019, primarily all of the Company’s products were manufactured by two vendors in China and by the Company’s facilities in Arizona.