GEOGRAPHIC AND OPERATING SEGMENT INFORMATION - Summary of Revenue by Geographic Area as a Percentage of Total Revenue (Details) - Revenue - Geographical area	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue by geographic area and by customer
Percentage of total revenue	100.00%	100.00%	100.00%
United States
Revenue by geographic area and by customer
Percentage of total revenue	66.00%	69.00%	71.00%
Europe, Middle East and Africa
Revenue by geographic area and by customer
Percentage of total revenue	14.00%	13.00%	13.00%
Japan
Revenue by geographic area and by customer
Percentage of total revenue	7.00%	10.00%	10.00%
Other Asia Pacific
Revenue by geographic area and by customer
Percentage of total revenue	7.00%	5.00%	4.00%
Other
Revenue by geographic area and by customer
Percentage of total revenue	6.00%	3.00%	2.00%