Equity Incentive Plans, Stock Compensation Expensed (Details) (USD $)	3 Months Ended
	Jun. 30, 2011		Jun. 30, 2010
Stock-based compensation expense [Line Items]
Allocated share based compensation expense	$ 7,856,000		$ 8,289,000
Inventory [Member]
Stock-based compensation expense [Line Items]
Amount of share-based compensation expense capitalized to inventory	1,700,000		2,000,000
Cost of sales [Member]
Stock-based compensation expense [Line Items]
Allocated share based compensation expense	1,399,000	[1]	1,965,000	[1]
Research and development [Member]
Stock-based compensation expense [Line Items]
Allocated share based compensation expense	3,413,000		3,167,000
Selling, general and administrative [Member]
Stock-based compensation expense [Line Items]
Allocated share based compensation expense	4,212,000		4,319,000
Pre-tax effect of share based compensation [Member]
Stock-based compensation expense [Line Items]
Allocated share based compensation expense	9,024,000		9,451,000
Income tax benefit [Member]
Stock-based compensation expense [Line Items]
Allocated share based compensation expense	$ 1,168,000		$ 1,162,000

[1] 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 expenses in inventory was sold.  During the three months ended June 30, 2010, $2.0 million of share-based compensation expense was capitalized to inventory and $2.0 million of previously capitalized share-based compensation expense in inventory was sold.