Stock-Based Compensation (Tables)

6 Months Ended

Sep. 30, 2013

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of assumptions used in the Black-Scholes valuation model

The estimated assumptions used in the Black-Scholes valuation model to value our ESPP were as follows:

	Three Months Ended September 30,
	2013		2012
Risk-free interest rate	0.1	%	0.1 - 0.2%
Expected volatility	36 - 37%		41 - 42%
Weighted-average volatility	37	%	41	%
Expected term	6 - 12 months		6 - 12 months
Expected dividends	None		None

Schedule Of Assumptions Used In Monte-Carlo Simulation Model

The estimated assumptions used in the Monte-Carlo simulation model to value our market-based restricted stock units were as follows:

	Six Months Ended September 30,
	2013		2012
Risk-free interest rate	0.4	%	0.2 - 0.4%
Expected volatility	16 - 58%		17 - 116%
Weighted-average volatility	31	%	36	%
Expected dividends	None		None

Schedule Of Stock-Based Compensation Expense By Statement Of Operations

The following table summarizes stock-based compensation expense resulting from stock options, restricted stock, restricted stock units and the ESPP included in our Condensed Consolidated Statements of Operations (in millions):

	Three Months Ended September 30,				Six Months Ended September 30,
	2013		2012		2013		2012
Cost of revenue	$	1	$	—	$	1	$	1
Research and development(a)	23		26		43		47
Marketing and sales (a)	6		9		13		16
General and administrative (a)	8		9		14		19
Stock-based compensation expense	$	38	$	44	$	71	$	83

Employee Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Disclosure Of Stock-Based Compensation Arrangements By Stock-Based Payment Award

The following table summarizes our stock option activity for the six months ended September 30, 2013:

	Options (in thousands)		Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in millions)
Outstanding as of March 31, 2013	7,802		$	34.17
Granted	7		21.02
Exercised	(1,822	)	17.98
Forfeited, cancelled or expired	(537	)	45.90
Outstanding as of September 30, 2013	5,450		38.41		3.85	$	17
Vested and expected to vest	5,430		38.49		3.83	$	17
Exercisable as of September 30, 2013	5,204		39.46		3.66	$	14

Restricted Stock Rights [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Disclosure Of Stock-Based Compensation Arrangements By Stock-Based Payment Award

The following table summarizes our restricted stock rights activity, excluding performance-based and market-based restricted stock unit activity discussed below, for the six months ended September 30, 2013:

	Restricted Stock Rights (in thousands)		Weighted- Average Grant Date Fair Value
Balance as of March 31, 2013	15,918		$	16.85
Granted	6,491		22.64
Vested	(5,166	)	17.29
Forfeited or cancelled	(1,267	)	17.64
Balance as of September 30, 2013	15,976		19.00

Performance Based Restricted Stock Units [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Disclosure Of Stock-Based Compensation Arrangements By Stock-Based Payment Award

The following table summarizes our performance-based restricted stock unit activity for the six months ended September 30, 2013:

	Performance- Based Restricted Stock Units (in thousands)		Weighted- Average Grant Date Fair Value
Balance as of March 31, 2013	1,324		$	51.54
Vested	(36	)	15.39
Forfeited or cancelled	(1,234	)	54.17
Balance as of September 30, 2013	54		15.39

Market-Based Restricted Stock Units [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Disclosure Of Stock-Based Compensation Arrangements By Stock-Based Payment Award

The following table summarizes our market-based restricted stock unit activity for the six months ended September 30, 2013.

	Market-Based Restricted Stock Units (in thousands)		Weighted- Average Grant Date Fair Value
Balance as of March 31, 2013	925		$	19.16
Granted	555		29.52
Vested	(304	)	16.01
Forfeited or cancelled	(114	)	24.93
Balance as of September 30, 2013	1,062		24.86