STOCK PLANS AND SHARE BASED COMPENSATION (Stock-Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 14,767	$ 14,282	$ 16,485
Unrecognized compensation costs	22,750
Cost of revenues [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	933	879	1,074
Research and Development Expense [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	5,255	4,784	5,746
Selling and Marketing Expense [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	3,644	3,540	3,642
General and Administrative Expense [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 4,935	5,079	6,023
Stock Options [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Awards vesting period	4 years
Stock-based compensation expense	$ 700	1,200	2,300
Unrecognized compensation costs	$ 173
Unrecognized compensation costs, period of recognition (in years)	4 months 15 days
Performance Based Awards [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 300	500	3,200
Long-Term Performance-based Awards [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized compensation costs	$ 538
Unrecognized compensation costs, period of recognition (in years)	1 year 6 months 20 days
Restricted Stock Units (RSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Awards vesting period	4 years
Stock-based compensation expense	$ 12,700	11,300	9,800
Unrecognized compensation costs	$ 21,930
Unrecognized compensation costs, period of recognition (in years)	2 years 3 months 14 days
Employee Stock [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 1,200	$ 1,300	$ 1,200
Unrecognized compensation costs	$ 109
Unrecognized compensation costs, period of recognition (in years)	1 month

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 14.F)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14
-Section F

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Unrecognized cost of unvested share-based compensation awards.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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