STOCK PLANS AND SHARE-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-based Compensation Expense

The following table summarizes the stock-based compensation expense recognized in accordance with ASC 718-10 for the three and six months ended June 30, 2015, and June 30, 2014 (in thousands).

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2015		2014		2015		2014
Cost of revenues	$	257	$	298	$	506	$	517
Research and development	1,306		1,339		2,697		2,551
Sales and marketing	878		864		1,890		1,799
General and administrative	1,309		1,674		3,048		3,223
Total stock-based compensation expense	$	3,750	$	4,175	$	8,141	$	8,090

Schedule of Unrecognized Compensation Expense for Unvested Awards

The following table summarizes total compensation expense related to unvested awards not yet recognized, net of expected forfeitures, and the weighted-average period over which it is expected to be recognized as of June 30, 2015.

	June 30, 2015
	Unrecognized Compensation Expense for Unvested Awards (in thousands)			Weighted Average Remaining Recognition Period (in years)
Options		$	424		0.79
Performance-based awards		429			0.50
Long-term performance-based awards		2,778			2.04
Restricted stock units		26,855			2.70
Purchase plan		110			0.50
Total unrecognized compensation expense		$	30,596

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

The fair value of employees’ stock purchase rights under the Purchase Plan was estimated using the Black-Scholes model with the following weighted-average assumptions:        

	*Three Months Ended		Six Months Ended
	June 30,		June 30,
	2015	2014	2015	2014
Risk-free interest rates	—%	—%	0.07%	0.07%
Expected volatility rates	—%	—%	34%	30%
Expected dividend yield	—%	—%	0.89%	0.66%
Expected term of purchase right (in years)	0	0	0.5	0.5
Weighted-average estimated fair value of purchase rights	$—	$—	$12.89	$13.31

__________________________    

*There were no employee stock purchase rights granted in the three months ended June 30, 2015 and 2014.

Summary of Option Activity Under the Plans

A summary of stock option activity under the Plans, excluding performance-based awards and restricted stock units, as of June 30, 2015, and changes during the six months then ended, is presented below:

	Shares (in thousands)		Weighted- Average Exercise Price	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	1,344		$27.27
Granted	—		—
Exercised	(74	)	$25.45
Forfeited or expired	—		—
Outstanding at June 30, 2015	1,270		$27.37	3.15	$	22,627
Exercisable at June 30, 2015	1,243		$27.03	3.07	$	22,559
Vested and expected to vest at June 30, 2015	1,270		$27.36	3.15	$	22,626

Performance Based Awards (PSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

A summary of performance-based awards outstanding as of June 30, 2015, and activity during the six months then ended, is presented below:

	Shares (in thousands)	Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	—	—
Granted	88	$52.45
Vested	—	—
Change in units due to performance achievement for PSUs vested in the year	—	—
Forfeited or expired	—	—
Outstanding at June 30, 2015	88	$52.45	0.50	$	3,980
Outstanding and expected to vest at June 30, 2015	14		0.50	$	637

Long-Term Performance-based Awards (PRSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

A summary of long-term performance-based awards outstanding as of June 30, 2015, and activity during the six months then ended, is presented below:

	Shares (in thousands)	Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	61	$55.51
Granted	72	$52.47
Vested	—	—
Forfeited or expired	—	—
Outstanding at June 30, 2015	133	$53.87	2.04	$	5,995
Outstanding and expected to vest at June 30, 2015	76		2.03	$	3,440

Restricted Stock Units (RSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

A summary of RSUs outstanding as of June 30, 2015, and changes during the six months then ended, are as follows:

	Shares (in thousands)		Weighted- Average Grant Date Fair Value Per Share	Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding at January 1, 2015	692		$43.86
Granted	282		$50.43
Vested	(248	)	$42.53
Forfeited or expired	(19	)	$44.33
Outstanding at June 30, 2015	707		$46.93	1.69	$	31,938
Outstanding and expected to vest at June 30, 2015	649			1.63	$	29,317