Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

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

Total number of shares authorized, outstanding and available for future grants under the Stock Plans

As of December 31, 2013, the total number of shares authorized, outstanding and available for future grants under the Stock Plans was as follows:

Plan Name	Shares Authorized	Shares Outstanding	Shares Available for Future Grants
Amended and Restated 2007 Long-Term Incentive Plan	28,789,197	12,016,730	5,760,151
Other Stock Plans	14,252,015	1,009,111	—
Total	43,041,212	13,025,841	5,760,151

Composition of equity awards outstanding

The composition of the equity awards outstanding as of December 31, 2012 and 2013 was as follows: 

	December 31, 2012	December 31, 2013
Restricted stock	2,800,230	3,538,271
Stock options	9,032,512	9,487,570
Total outstanding awards	11,832,742	13,025,841

Restricted Stock Unit (RSU) and Restricted Stock Award (RSA) activity

The following table summarizes our RSU and RSA activity for the year ended December 31, 2013:

	Number of Units or Shares	Weighted-Average Grant-Date Fair Value
Outstanding at December 31, 2012	2,800,230	$	25.57
Granted	1,542,948	$	39.24
Released	(588,550)	$	35.43
Cancelled	(216,357)	$	42.23
Outstanding at December 31, 2013	3,538,271	$	28.79
Expected to vest after December 31, 2013*	3,106,300	$	29.78

*Includes reduction of shares outstanding due to estimated forfeitures

Stock option activity

The following table summarizes the stock option activity for the year ended December 31, 2013: 

	Number of Shares	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Life	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2012	9,032,512	$	21.11	5.27	$	480,191
Granted	3,128,561	$	43.95
Exercised	(2,125,859)	$	8.29
Cancelled	(547,644)	$	40.98
Outstanding at December 31, 2013	9,487,570	$	30.37	5.10	$	117,886
Vested and exercisable at December 31, 2013	4,423,014	$	15.64	4.21	$	109,170
Vested and exercisable at December 31, 2013 and expected to vest thereafter*	8,646,666	$	28.98	5.00	$	117,319

*Includes reduction of shares outstanding due to estimated forfeitures

Assumptions used to estimate the fair values of the stock options granted

The following table presents the assumptions used to estimate the fair values of the stock options granted in the periods presented:

	Years Ended December 31,
	2011	2012	2013
Expected stock volatility	56% - 57%	56% - 58%	46% - 47%
Expected dividend yield	—%	—%	—%
Risk-free interest rate	0.85% - 2.35%	0.50% - 0.77%	0.57% - 0.93%
Expected life	4.75 years	4.00 - 4.75 years	3.79 years
Weighted-average grant-date fair value of options granted during the year	$18.09	$24.38	$15.86

Assumptions used to estimate the fair values of the shares granted through the Employee Stock Purchase Program (ESPP)

The following table presents the assumptions used to estimate the fair values of the shares granted through the ESPP in the periods presented:

	Years Ended December 31,
	2012	2013
Expected stock volatility	41% - 53%	32% - 62%
Expected dividend yield	—%	—%
Risk-free interest rate	0.06% - 0.27%	0.09% - 0.34%
Expected life	0.5 - 2.0 years	0.5 - 2.0 years
Weighted-average grant-date fair value of shares granted during the year	$14.98	$16.04

Allocation of share-based compensation expense to income statement line items

Share-based compensation expense was recognized as follows: 

	Year Ended December 31,
(in thousands)	2011			2012			2013
Cost of revenue	$	7,482		$	9,592		$	12,584
Research and development	2,975			4,856			8,168
Sales and marketing	2,408			6,379			7,317
General and administrative	15,908			20,719			31,576
Pre-tax share-based compensation	28,773			41,546			59,645
Less: Income tax benefit	(9,890		)	(15,477		)	(20,080		)
Total share-based compensation expense, net of tax	$	18,883		$	26,069		$	39,565

The Company has made certain reclassifications to the prior year amounts above in order to conform to the current year's presentation. Refer to Note 1, "Company Overview, Basis of Presentation, and Summary of Significant Accounting Policies," for more information about these reclassifications.