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Geographic Information and Major Customer and Product Data (Details 2)
9 Months Ended 12 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Total revenues [Member] | Customer A [Member]          
Revenue, Major Customer [Line Items]          
Concentration risk 13.13% 47.70% 38.00% 35.20% 33.30%