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6. Customer Concentrations (Details Narrative)
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Three Customers Percentage of Sales    
Percent concentration 70.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_MajorCustomersAxis
= ZMTP_ThreeCustomersSalesMember		 73.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_MajorCustomersAxis
= ZMTP_ThreeCustomersSalesMember
One Customer Percentage of Sales    
Percent concentration 40.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_MajorCustomersAxis
= ZMTP_OneCustomerSalesMember		 56.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_MajorCustomersAxis
= ZMTP_OneCustomerSalesMember
Three Customers Percentage of Receivables    
Percent concentration 87.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_MajorCustomersAxis
= ZMTP_ThreeCustomersReceivablesMember		  
One Customer Percentage of Receivables    
Percent concentration 62.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_MajorCustomersAxis
= ZMTP_OneCustomerReceivablesMember