STOCK PLANS AND SHARE BASED COMPENSATION (Stock-Based Compensation) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 16,485	$ 14,224	$ 8,969
Unrecognized compensation costs	21,200
Cost of revenues [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	1,074	1,058	666
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	5,746	5,503	3,274
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	3,642	3,317	2,313
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	6,023	4,346	2,716
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	2,300	4,000	4,000
Unrecognized compensation costs	2,000
Unrecognized compensation costs, period of recognition (in years)	1 year 6 months 11 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
Unrecognized compensation costs	0
Unrecognized compensation costs, period of recognition (in years)	0 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	9,800	7,000	3,800
Unrecognized compensation costs	19,100
Unrecognized compensation costs, period of recognition (in years)	2 years 5 months 19 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	1,100	1,200
Unrecognized compensation costs	$ 100
Unrecognized compensation costs, period of recognition (in years)	6 months