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Concentrations - Concentration of Credit Risk and Concentration of Net Sales (Details) - Customer Concentration Risk
3 Months Ended 12 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Accounts Receivable | Verizon      
Concentration Risk [Line Items]      
Percentage of sales 26.00%   24.00%
Accounts Receivable | Best Buy      
Concentration Risk [Line Items]      
Percentage of sales 7.00%   14.00%
Revenue from Contract with Customer | Verizon      
Concentration Risk [Line Items]      
Percentage of sales 24.00% 7.00%  
Revenue from Contract with Customer | Best Buy      
Concentration Risk [Line Items]      
Percentage of sales 10.00% 10.00%