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 50

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- Definition

Unrecognized cost of unvested share-based compensation awards.

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- Definition

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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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, 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, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 14,282	$ 16,485	$ 14,224
Unrecognized compensation costs	22,470
Cost of revenues [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	879	1,074	1,058
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	4,784	5,746	5,503
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	3,540	3,642	3,317
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	5,079	6,023	4,346
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	1,200	2,300	4,000
Unrecognized compensation costs	786
Unrecognized compensation costs, period of recognition (in years)	1 year 1 month 9 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		3,200	2,100
Long-Term Performance-based Awards [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	500
Unrecognized compensation costs	1,255
Unrecognized compensation costs, period of recognition (in years)	2 years
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	11,300	9,800	7,000
Unrecognized compensation costs	20,285
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	1,300	1,200	1,100
Unrecognized compensation costs	$ 144
Unrecognized compensation costs, period of recognition (in years)	6 months