Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2015

Stock-Based Compensation

Stock-based compensation expense

The Company recorded stock-based compensation expense as follows (in millions):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2015		2014		2015		2014
Stock options	$	2.0	$	1.7	$	5.3	$	4.7
Restricted stock	0.2		0.4		0.5		2.4
Total stock-based compensation	$	2.2	$	2.1	$	5.8	$	7.1

Assumptions regarding volatility, expected life, dividend yield and risk-free interest rates

Assumptions regarding volatility, expected life, dividend yield and risk-free interest rates are required for the Black-Scholes model and are presented in the table below:

	2015	2014
Risk-free interest rates	1.58% - 1.89%	1.81% - 2.10%
Expected life	6.0-6.25 years	6.0 - 6.25 years
Volatility	36.09% - 52.23%	53.24% - 56.24%
Expected dividend yield	0.0%	0.0%

Schedule of stock option activity

Stock option activity for the nine months ended September 30, 2015 was as follows:

	Shares Subject to Options		Weighted Average Option Price		Weighted Average Remaining Contractual Term (Yrs)	Aggregate Intrinsic Value (in millions) (b)
Outstanding at December 31, 2014	4,810,588		$	15.24
Granted	1,082,819		19.80
Exercised	(616,052	)	11.68
Forfeited	(324,779	)	19.16
Outstanding at September 30, 2015	4,952,576		$	16.42	6.6	$	9.7
Exercisable at September 30, 2015	2,596,387		$	13.82	4.9	$	9.0
Exercisable and expected to vest at September 30, 2015 (a)	4,815,917		$	16.34	6.5	$	9.7

(a)	In addition to the options that are vested at September 30, 2015, the Company expects a portion of the unvested options to vest in the future. Options expected to vest in the future are determined by applying an estimated forfeiture rate to the options that are unvested as of September 30, 2015.
(b)	The aggregate intrinsic value is based on the positive difference between the fair value of the Company’s common stock price of $16.43 on September 30, 2015, or the date of exercises, as appropriate, and the exercise price of the underlying stock options.

Schedule of restricted stock activity

Restricted stock activity for the nine months ended September 30, 2015 was as follows:

	Shares Subject to Restriction		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2014	309,725		$	17.20
Granted	130,274		19.72
Vested	(56,395	)	17.02
Forfeited	(145,857	)	17.42
Outstanding at September 30, 2015	237,747		$	18.49