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

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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STOCK PLANS AND SHARE-BASED COMPENSATION (Stock-Based Compensation) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 3,750	$ 4,175	$ 8,141	$ 8,090
Unrecognized Compensation Expense for Unvested Awards	30,596		30,596
Stock Options [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	200	500	400	1,000
Unrecognized Compensation Expense for Unvested Awards	424		$ 424
Weighted Average Remaining Recognition Period (in years)			290 days
Performance Based Awards and Long Term Performance based Units [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	200	700	$ 800	1,300
Performance Based Awards (PSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized Compensation Expense for Unvested Awards	429		$ 429
Weighted Average Remaining Recognition Period (in years)			183 days
Long-Term Performance-based Awards (PRSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized Compensation Expense for Unvested Awards	2,778		$ 2,778
Weighted Average Remaining Recognition Period (in years)			2 years 15 days
Restricted Stock Units (RSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	3,100	2,700	$ 6,300	5,200
Unrecognized Compensation Expense for Unvested Awards	26,855		$ 26,855
Weighted Average Remaining Recognition Period (in years)			2 years 8 months 12 days
Employee Stock [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	300	300	$ 600	600
Unrecognized Compensation Expense for Unvested Awards	110		$ 110
Weighted Average Remaining Recognition Period (in years)			6 months
Cost of revenues [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	257	298	$ 506	517
Research and development [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	1,306	1,339	2,697	2,551
Sales and marketing [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	878	864	1,890	1,799
General and administrative [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 1,309	$ 1,674	$ 3,048	$ 3,223