Equity Incentive Plans, Stock Compensation Expensed (Details) (USD $)	3 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	$ 8,664,000		$ 7,856,000
Inventory [Member]
Stock-based compensation expense [Line Items]
Amount of share-based compensation expense capitalized to inventory	1,700,000		1,700,000
Cost of Sales [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	1,310,000	[1]	1,399,000	[1]
Research and development [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	4,032,000		3,413,000
Selling, general and administrative [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	4,644,000		4,212,000
Pre-tax effect of share based compensation [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	9,986,000		9,024,000
Income tax benefit [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	$ 1,322,000		$ 1,168,000

[1] During the three months ended June 30, 2012, $1.7 million of share-based compensation expense was capitalized to inventory and $1.3 million of previously capitalized share-based compensation expenses in inventory was sold. During the three months ended June 30, 2011, $1.7 million of share-based compensation expense was capitalized to inventory and $1.4 million of previously capitalized share-based compensation expense in inventory was sold.