STOCK PLANS AND SHARE BASED COMPENSATION (Stock-Based Compensation) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	$ 3,031,000	$ 2,504,000
Stock compensation expense	3,000,000	2,500,000
Cost of revenues [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	245,000	239,000
Research and Development [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	1,120,000	811,000
Sales and Marketing [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	747,000	667,000
General and Administrative [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Stock-based compensation expense	919,000	787,000
Stock Options [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized compensation costs	5,000,000
Unrecognized compensation costs, period of recognition (in years)	1.7
Stock compensation expense	900,000	1,200,000
Performance-based Awards [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized compensation costs	2,800,000
Stock compensation expense	400,000	300,000
Restricted Stock Units (RSUs) [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized compensation costs	11,300,000
Unrecognized compensation costs, period of recognition (in years)	2.6
Stock compensation expense	1,400,000	600,000
Employees Stock Purchase Plan [Member]
Stock-based compensation expense for stock options, stock awards and employee stock purchases included in operations:
Unrecognized compensation costs	400,000
Unrecognized compensation costs, period of recognition (in years)	0.5
Stock compensation expense	$ 300,000	$ 300,000