Stock Options and Restricted Stock (Tables)

6 Months Ended

Jun. 30, 2012

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

Schedule of Share-based Compensation, Stock Options, Activity

The following table summarizes stock option activity:

	Number of Shares		Weighted-Average Exercise Price		Aggregate Intrinsic Value(1)		Weighted-Average Remaining Contractual Term (in years)
Balance, December 31, 2011	9,086,586		$	10.79	$	86,590	7.3
Options granted (3)	626,500		$	25.03
Exercised	(71,442	)	$	18.92
Canceled/forfeited	(399,652	)	$	19.09
Balance, June 30, 2012	9,241,992		$	11.33	$	140,159	6.9
Vested and exercisable as of June 30, 2012	5,780,981		$	8.09	$	106,431	5.9
Vested and exercisable as of June 30, 2012 and expected to vest thereafter (2)	8,653,670		$	10.85	$	135,450	6.8

(1) The aggregate intrinsic value is calculated as the difference between the exercise price of the underlying award and the fair value of $26.50, and $20.14 of our common stock on June 30, 2012, and December 31, 2011.

(2) Stock options expected to vest reflect an estimated forfeiture rate.

(3) Includes 242,500 shares granted to non-employees. The assumptions used to value these grants are similar to those used for grants made to employees with the exception of the expected term.

Schedule of Share-based Payment Awards, Valuation Assumptions

The following weighted-average assumptions were used for grants made to employees and do not include the assumptions for non-employee grants:

	June 30, 2012		December 31, 2011
Risk-free interest rate	1.0	%	1.8	%
Expected volatility	44.6	%	43.8	%
Expected life (in years)	6		6
Dividend yield	—	%	—	%

Share-based Payment Awards, Summary of Outstanding and Exercisable Options by Exersise Price Range

The following table summarizes information concerning outstanding and exercisable options as of June 30, 2012:

	Options Outstanding				Options Exercisable and Vested
Range of Exercise Prices	Number of Shares	Weighted Average Remaining Contractual Life (in Years)	Weighted- Average Exercise Price		Number of Shares	Weighted- Average Exercise Price
$  1.00 - $  1.40	971,103	2.4	$	1.16	971,103	$	1.16
$2.98	216,240	4.3	$	2.98	216,240	$	2.98
$5.00	1,362,500	4.9	$	5.00	1,362,500	$	5.00
$7.50	1,737,000	7.0	$	7.50	1,284,822	$	7.50
$11.29	255,000	7.6	$	11.29	166,041	$	11.29
$13.00	955,000	7.5	$	13.00	562,597	$	13.00
$14.82	1,905,316	8.3	$	14.82	840,814	$	14.82
$15.50 - $21.00	1,153,333	8.6	$	19.03	355,614	$	17.87
25.50 - 26.50	686,500	9.7	$	25.74	21,250	25.50
$  1.00 - $26.50	9,241,992	6.9	$	11.33	5,780,981	$	8.09