STOCK PLANS AND SHARE BASED COMPENSATION (Details) (USD $)	12 Months Ended				12 Months Ended			1 Months Ended	12 Months Ended								1 Months Ended	12 Months Ended		1 Months Ended
	Dec. 31, 2013 plans	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 2007 Equity Incentive Plan [Member]	Dec. 31, 2013 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2011 Restricted Stock Units (RSUs) [Member]	Jul. 31, 2012 Restricted Stock Units (RSUs) [Member] Directors Equity Compensation Program [Member]	Dec. 31, 2013 Employee Stock [Member] purchaseperiods	Dec. 31, 2012 Employee Stock [Member]	Dec. 31, 2011 Employee Stock [Member]	Dec. 31, 2013 Incentive Stock Options [Member] 2007 Equity Incentive Plan [Member]	Dec. 31, 2013 Stock Options [Member]	Dec. 31, 2012 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2013 Stock Options [Member] 2007 Equity Incentive Plan [Member]	Jul. 31, 2012 Stock Options [Member] Directors Equity Compensation Program [Member]	Dec. 31, 2013 Nonstatutory Stock Options [Member] 2007 Equity Incentive Plan [Member]	Dec. 31, 2013 Nonstatutory Stock Options [Member] Directors Equity Compensation Program [Member]	Jul. 31, 2012 Stock Options and Restricted Stock Units (RSUs) [Member] Directors Equity Compensation Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs	$ 21,200,000				$ 19,100,000				$ 100,000				$ 2,000,000
Unrecognized compensation costs, period of recognition (in years)					2 years 5 months 19 days				6 months				1 year 6 months 11 days
Number of stock-based compensation plans	2
Exercise price of stock options as percentage of fair market value on date of grant, minimum												100.00%						100.00%
Multiplier for calculation of common stock options granted to directors on the first trading day of the month following commencement of service																			8,000
Number of options granted to directors on the first trading day of July following commencement of service																			24,000
Awards vesting period					4 years								4 years			48 months			3 years
Awards expiration period, maximum																10 years
Maximum percentage of employee's compensation eligible for payroll deductions									15.00%
Purchase price of the purchase plan as percentage of the lower of the fair market value on the first day of each offering period or on the purchase date									85.00%
Number of purchase period in each offering period									1
Duration of each purchase period in each offering period									6 months
Shares reserved for issuance									3,000,000
Number of shares purchased									2,599,102
Number of shares available for future issuance				7,176,041					400,898
Common stock reserved for future issuance under stock option and stock purchase plans	3,900,000
Stock-based compensation expense	16,485,000	14,224,000	8,969,000		9,800,000	7,000,000	3,800,000		1,200,000	1,100,000	1,200,000		2,300,000	4,000,000	4,000,000
Factor used to determine the number of options/units to be purchased								$ 100,000									$ 100,000			$ 100,000