Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2013

Summary of the status of the company's stock option plan

A summary of the Company’s stock option activity for the three months ended March 31, 2013 is as follows (share numbers and aggregate intrinsic values in thousands):



	Number of Options Outstanding		Weighted Average Exercise Price		Weighted Average Contractual Term (Years)	Aggregate Intrinsic Value
Balances, December 31, 2012	2,034		$	17.09
Granted	2		32.99
Exercised	(947	)	13.08
Forfeited, cancelled or expired	(22	)	27.65
Balances, March 31, 2013	1,067		$	20.46	5.8	$	25,898
Options vested and expected to vest at March 31, 2013	1,037		$	20.15	5.7	$	25,488
Options vested at March 31, 2013	773		$	17.00	4.8	$	21,268

Assumption used to value options granted during the period

The assumptions used to value options granted during the three months ended March 31, 2013 and 2012 were as follows:



	Three Months Ended
	March 31,
	2013		2012
Dividend yield	—		—
Annual risk free rate of return	0.8	%	0.9	%
Expected volatility	47.0	%	58.7	%
Expected term (years)	4.2		4.3

Summary of company restricted stock unit activity

A summary of the Company’s RSU activity for the three months ended March 31, 2013, is as follows (share numbers in thousands):



	Number of Units Outstanding		Weighted Average Grant Date Fair Value
Awarded and unvested, December 31, 2012	3,252		$	31.10
Granted	1,268		41.33
Vested	(664	)	28.66
Forfeited	(58	)	34.69
Awarded and unvested, March 31, 2013	3,798		$	34.89
Restricted stock units expected to vest, March 31, 2013	3,250