STOCK PLANS AND SHARE-BASED COMPENSATION (Stock-Based Compensation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 4,391	$ 3,915
Unrecognized Compensation Expense for Unvested Awards	28,535
Employee Stock Option [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	200	500
Unrecognized Compensation Expense for Unvested Awards	587
Weighted Average Remaining Recognition Period (in years)	11 months 8 days
Performance Based Awards (PSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	600	500
Unrecognized Compensation Expense for Unvested Awards	1,256
Weighted Average Remaining Recognition Period (in years)	9 months
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	3,879
Weighted Average Remaining Recognition Period (in years)	2 years 3 months 3 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	3,300	2,600
Unrecognized Compensation Expense for Unvested Awards	22,379
Weighted Average Remaining Recognition Period (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	300	300
Unrecognized Compensation Expense for Unvested Awards	434
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	249	219
Research and development [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	1,391	1,212
Sales and marketing [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	1,012	935
General and administrative [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 1,739	$ 1,549

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

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Unrecognized cost of unvested share-based compensation awards.

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