Annual report pursuant to Section 13 and 15(d)

Industry, Segment and Geographic Information - Concentration (Details)

v3.3.1.900
Industry, Segment and Geographic Information - Concentration (Details) - customer
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Top five customers      
Significant Customers and Vendors      
Number of customers 5 5 5
Net sales | Customer concentration risk      
Significant Customers and Vendors      
Number of customers 2    
Percentage of concentration risk 10.00%    
Net sales | SHI | Customer concentration risk      
Significant Customers and Vendors      
Percentage of concentration risk 19.00% 17.40% 14.90%
Net sales | CDW | Customer concentration risk      
Significant Customers and Vendors      
Percentage of concentration risk 17.90% 16.40% 13.80%
Net sales | Insight Enterprises, Inc. ("Insight") | Customer concentration risk      
Significant Customers and Vendors      
Percentage of concentration risk   11.00% 12.20%
Net sales | Top five customers      
Significant Customers and Vendors      
Percentage of concentration risk 52.00% 52.00% 48.00%
Net accounts receivable | SHI | Customer concentration risk      
Significant Customers and Vendors      
Percentage of concentration risk 14.00%    
Net accounts receivable | CDW | Customer concentration risk      
Significant Customers and Vendors      
Percentage of concentration risk 21.90%    
Purchases | Vendor concentration risk      
Significant Customers and Vendors      
Percentage of concentration risk 10.00% 10.00% 10.00%
Purchases | Vendor concentration risk | Dell/Quest Software      
Significant Customers and Vendors      
Percentage of concentration risk     10.20%
Purchases | Vendor concentration risk | Sophos      
Significant Customers and Vendors      
Percentage of concentration risk 24.20% 14.70%