SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration Risk (Details) - Net Sales	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Customer | Single Customer | Maximum
Concentration risk
Percentage of total net sales	2.00%	2.00%	2.00%
Customer | Federal Government Agencies
Concentration risk
Percentage of total net sales	7.50%	6.70%	6.50%
Customer | Single Federal Government Agency | Maximum
Concentration risk
Percentage of total net sales	2.00%	2.00%	2.00%
Supplier | Ingram Micro Inc Class
Concentration risk
Percentage of product purchases	21.00%	21.00%	25.00%
Supplier | Synnex Corporation
Concentration risk
Percentage of product purchases	13.00%	15.00%	13.00%
Supplier | Other vendor suppliers | Maximum
Concentration risk
Percentage of product purchases	10.00%	10.00%	10.00%
Supplier | Hewlett Packard Company
Concentration risk
Products manufactured by HP as a percentage of net sales	20.00%	22.00%	22.00%