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Accounts Receivable and Significant Concentrations (Details) - USD ($)
Sep. 30, 2019
Dec. 31, 2018
Accounts receivable, gross $ 7,077,564 $ 11,196,048
Less: allowances for doubtful accounts 125,496 106,733
Accounts receivable, net 6,952,068 11,089,315
Government [Member]    
Accounts receivable, gross 5,155,811 7,332,338
Commercial [Member]    
Accounts receivable, gross $ 1,921,753 $ 3,863,710