Equity Incentive Plans, Stock Compensation Expensed (Details) (USD $)	3 Months Ended				6 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	$ 17,134,000		$ 8,258,000		$ 25,798,000		$ 16,114,000
Unrecognized compensation expense related to unvested share based payment awards	86,800,000				86,800,000
Weighted average period of unearned share-based compensation expected to be recognized (in years)					1.88
Inventory [Member]
Stock-based compensation expense [Line Items]
Amount of share-based compensation expense capitalized to inventory	1,800,000		1,700,000		3,500,000		3,300,000
Cost of Sales [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	2,614,000	[1]	1,608,000	[1]	3,924,000	[1]	3,007,000	[1]
Research and development [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	6,358,000		3,556,000		10,390,000		6,969,000
Selling, general and administrative [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	11,581,000		4,320,000		16,225,000		8,532,000
Pre-tax effect of share based compensation [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	20,553,000		9,484,000		30,539,000		18,508,000
Income tax benefit [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	$ 3,419,000		$ 1,226,000		$ 4,741,000		$ 2,394,000

[1] During the three and six months ended September 30, 2012, $1.8 million and $3.5 million, respectively, of share-based compensation expense was capitalized to inventory and $2.6 million and $3.9 million, respectively, of previously capitalized share-based compensation expenses in inventory was sold. During the three and six months ended September 30, 2011, $1.7 million and $3.3 million, respectively, of share-based compensation expense was capitalized to inventory and $1.6 million and $3.0 million, respectively, of previously capitalized share-based compensation expense in inventory was sold.