Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2014

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

	Three Months Ended March 31,
	2014		2013
Stock options	$	1.6	$	1.6
Restricted stock	0.4		0.2
Total stock-based compensation	$	2.0	$	1.8

Assumptions regarding volatility, expected term, dividend yield and risk-free interest rate

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:

	2014	2013
Risk-free interest rates	1.81% - 2.04%	1.22% - 1.43%
Expected life	6.0 - 6.3 years	6.5 years
Volatility	55.5% - 56.2%	54.9%
Expected dividend yield	0.0%	0.0%

Schedule of stock option activity

Stock option activity for the three months ended March 31, 2014 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, 2013	4,877,564		$	13.12
Granted	99,200		19.52
Exercised	(291,140	)	10.28
Forfeited	(86,713	)	14.42
Outstanding at March 31, 2014	4,598,911		$	13.41	6.3	$	47.2

Exercisable at March 31, 2014	2,618,211		$	10.92	4.6	$	34.3

Excercisable and expected to vest at March 31, 2014 (a)	4,460,262		$	13.31	6.2	$	45.5

(a) In addition to the options that are vested at March 31, 2014, 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 March 31, 2014.

(b) The aggregate intrinsic value is based on the positive difference between the fair value of the Company’s common stock price of $22.79 on March 31, 2014, 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 three months ended March 31, 2014 was as follows:

	Shares Subject to Restriction		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2013	357,948		$	16.65
Vested	(1,375	)	16.57
Outstanding at March 31, 2014	356,573		$	16.65