Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2015

Stock-Based Compensation

Summary of stock option activity

Presented below is a summary of our stock option activity for the nine months ended September 30, 2015 (in thousands, except for weighted average exercise price and weighted average remaining contractual terms):

	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Terms	Aggregate Intrinsic Value
Outstanding at December 31, 2014	4,101		$	18.72
Granted	1,274		16.67
Exercised	(578	)	7.25
Forfeited	(518	)	21.61
Expired	(317	)	24.75
Outstanding at September 30, 2015	3,962		18.88		4.82	$	1,794
Expected to vest at September 30, 2015	2,410		19.48		5.91	—
Exercisable at September 30, 2015	1,498		$	17.87	3.03	$	1,794

Schedule of weighted -average assumptions used for estimating fair value of each stock option grant on the date of grant

	Nine months ended September 30,
	2015	2014
Expected dividend yield	—	—
Risk-free interest rate	1.55%	1.56%
Expected volatility	41.77%	38.11%
Expected life	4.90 years	4.81 years

Summary of status of restricted stock units

A summary of the status of our restricted stock units and of changes in restricted stock units outstanding under the 2006 Stock Plan for the nine months ended September 30, 2015 is as follows (in thousands, except for weighted average grant date fair value per unit):

	Number of Units		Weighted Average Grant Date Fair Value per Unit
Outstanding balance at December 31, 2014	910		$	22.84
Granted	665		16.69
Vesting of restricted stock units, net of shares withheld for taxes	(97	)	24.00
Shares withheld for taxes	(37	)	24.00
Forfeitures	(201	)	21.91
Outstanding balance at September 30, 2015	1,240		$	19.56