Stock-Based Compensation Expense

9 Months Ended

Sep. 30, 2015

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

Stock-Based Compensation Expense

STOCK-BASED COMPENSATION EXPENSE

The effect of recording stock-based compensation expense for the three and nine months ended September 30, 2015 and 2014 is as follows (in thousands):

	Three Months Ended				Nine Months Ended
	September 30, 2015		September 30, 2014		September 30, 2015		September 30, 2014
Cost of revenues	$	—	$	—	$	—	$	18
Research, development and other related costs	1,109		609		2,805		2,276
Selling, general and administrative	1,776		2,784		5,652		7,530
Total stock-based compensation expense	2,885		3,393		$	8,457	$	9,824

Stock-based compensation expense categorized by various equity components for the three and nine months ended September 30, 2015 and 2014 is summarized in the table below (in thousands):

	Three Months Ended				Nine Months Ended
	September 30, 2015		September 30, 2014		September 30, 2015		September 30, 2014
Employee stock options	$	635	$	781	$	2,142	$	2,582
Restricted stock awards and units	2,125		2,522		5,885		6,783
Employee stock purchase plan	125		90		430		459
Total stock-based compensation expense	$	2,885	$	3,393	$	8,457	$	9,824

The following assumptions were used to value the options granted:

	Three Months Ended				Nine Months Ended
	September 30, 2015		September 30, 2014		September 30, 2015	September 30, 2014
Expected life (in years)	3.8		4.9		3.8	4.9
Risk-free interest rate	1.3	%	1.8	%	1.1-1.4%	1.6-1.8%
Dividend yield	2.1	%	3.5	%	2.1 -2.9%	3.4 -4.1%
Expected volatility	34.0	%	37.3	%	34.0 - 35.6%	37.3 - 41.4%

ESPP grants occur in February and August. The following assumptions were used to value the ESPP shares for these grants:

	August 2015		August 2014		February 2015		February 2014
Expected life (years)	2.0		2.0		2.0		2.0
Risk-free interest rate	0.7	%	0.5	%	0.4	%	0.3	%
Dividend yield	2.1	%	3.5	%	3.4	%	3.4	%
Expected volatility	29.7	%	27.6	%	30.0	%	31.0	%