Stock-Based Compensation (Tables)

9 Months Ended

Dec. 31, 2012

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 stock option grants were as follows:

	Stock Option Grants								ESPP
	Three Months Ended December 31,				Nine Months Ended December 31,				Nine Months Ended December 31,
	2012		2011		2012		2011		2012		2011
Risk-free interest rate	0.4 - 1.0%		0.4 - 1.2%		0.4 - 1.0%		0.4 - 1.8%		0.1 - 0.2%		0.1	%
Expected volatility	40 - 45%		42 - 46%		40 - 46%		40 - 46%		41 - 42%		39 - 40%
Weighted-average volatility	41	%	45	%	43	%	43	%	41	%	39	%
Expected term	4.3 years		4.1 years		4.4 years		4.4 years		6 - 12 months		6 - 12 months
Expected dividends	None		None		None		None		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:

	Three Months Ended December 31,		Nine Months Ended December 31,
	2012		2012		2011
Risk-free interest rate	0.3	%	0.2 - 0.4%		0.2 - 0.6%
Expected volatility	33	%	17 - 116%		14 - 83%
Weighted-average volatility	33	%	35	%	35	%
Expected dividends	None		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 December 31,				Nine Months Ended December 31,
	2012		2011		2012		2011
Cost of revenue	$	—	$	—	$	1	$	1
Research and development	25		30		74		81
General and administrative	7		11		25		29
Marketing and sales	7		7		22		18
Stock-based compensation expense	$	39	$	48	$	122	$	129

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 nine months ended December 31, 2012:

	Options (in thousands)		Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in millions)
Outstanding as of March 31, 2012	9,774		$	34.17
Granted	292		13.10
Exercised	(17	)	13.08
Forfeited, cancelled or expired	(2,019	)	32.75
Outstanding as of December 31, 2012	8,030		33.82		4.75	$	—
Vested and expected to vest	7,968		33.97		4.72	$	—
Exercisable as of December 31, 2012	7,401		35.24		4.46	$	—

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 nine months ended December 31, 2012:

	Restricted Stock Rights (in thousands)		Weighted- Average Grant Date Fair Value
Balance as of March 31, 2012	16,323		$	20.73
Granted	8,684		12.62
Vested	(5,751	)	20.88
Forfeited or cancelled	(1,655	)	18.91
Balance as of December 31, 2012	17,601		16.85

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 nine months ended December 31, 2012:

	Performance- Based Restricted Stock Units (in thousands)		Weighted- Average Grant Date Fair Value
Balance as of March 31, 2012	1,421		$	50.35
Vested	(19	)	15.39
Forfeited or cancelled	(78	)	38.67
Balance as of December 31, 2012	1,324		51.54

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 nine months ended December 31, 2012. We present shares granted at 100 percent of target of the number of stock units that may potentially vest.

	Market-Based Restricted Stock Units (in thousands)		Weighted- Average Grant Date Fair Value
Balance as of March 31, 2012	520		$	34.77
Granted	970		12.41
Vested	(111	)	34.77
Forfeited or cancelled	(62	)	34.77
Balance as of December 31, 2012	1,317		18.30