REVENUE - Percentage of Net Sales (Details) - Revenue from Contract with Customer	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Product Concentration Risk | Protection (screen protection and cases)
Disaggregation of Revenue [Line Items]
Percentage of sales	63.00%	59.00%	60.00%	57.00%
Product Concentration Risk | Power (power management and power cases)
Disaggregation of Revenue [Line Items]
Percentage of sales	26.00%	31.00%	28.00%	31.00%
Product Concentration Risk | Productivity (keyboards and other)
Disaggregation of Revenue [Line Items]
Percentage of sales	6.00%	7.00%	9.00%	8.00%
Product Concentration Risk | Audio
Disaggregation of Revenue [Line Items]
Percentage of sales	5.00%	3.00%	3.00%	4.00%
Distribution Channel Concentration Risk | Indirect channel
Disaggregation of Revenue [Line Items]
Percentage of sales	84.00%	86.00%	82.00%	82.00%
Distribution Channel Concentration Risk | Online
Disaggregation of Revenue [Line Items]
Percentage of sales	12.00%	9.00%	14.00%	12.00%
Distribution Channel Concentration Risk | Franchisees
Disaggregation of Revenue [Line Items]
Percentage of sales	4.00%	5.00%	4.00%	6.00%
Geographic Concentration Risk | United States
Disaggregation of Revenue [Line Items]
Percentage of sales	74.00%	79.00%	78.00%	75.00%
Geographic Concentration Risk | Europe
Disaggregation of Revenue [Line Items]
Percentage of sales	19.00%	12.00%	16.00%	13.00%
Geographic Concentration Risk | Other
Disaggregation of Revenue [Line Items]
Percentage of sales	7.00%	9.00%	6.00%	12.00%