Share-Based Compensation (Details) (USD $)	3 Months Ended				6 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	$ 13,411,000		$ 17,134,000		$ 24,665,000		$ 25,798,000
Inventory [Member]
Stock-based compensation expense [Line Items]
Amount of share-based compensation expense capitalized to inventory	2,400,000		1,800,000		3,800,000		3,500,000
Cost of Sales [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	1,864,000	[1]	2,614,000	[1]	3,833,000	[1]	3,924,000	[1]
Research and development [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	6,931,000		6,358,000		12,621,000		10,390,000
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	6,205,000		11,581,000		11,202,000		16,225,000
Pre-tax effect of share based compensation [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	15,000,000		20,553,000		27,656,000		30,539,000
Income tax benefit [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	$ 1,589,000		$ 3,419,000		$ 2,991,000		$ 4,741,000

[1] During the three and six months ended September 30, 2013, $2.4 million and $3.8 million, respectively, of share-based compensation expense was capitalized to inventory and $1.9 million and $3.8 million, respectively, of previously capitalized share-based compensation expenses in inventory was sold. During the three and six months ended September 30, 2012, $1.8 million and $3.5 million of share-based compensation expense was capitalized to inventory and $2.6 million and $3.9 million, respectively, of previously capitalized share-based compensation expense in inventory was sold.