Share-Based Compensation (Details) (USD $)	3 Months Ended
	Jun. 30, 2013		Jun. 30, 2012
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	$ 11,254,000		$ 8,664,000
Inventory [Member]
Stock-based compensation expense [Line Items]
Amount of share-based compensation expense capitalized to inventory	1,400,000		1,700,000
Cost of Sales [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	1,969,000	[1]	1,310,000	[1]
Research and development [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	5,690,000		4,032,000
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	4,997,000		4,644,000
Pre-tax effect of share based compensation [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	12,656,000		9,986,000
Income tax benefit [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	$ 1,402,000		$ 1,322,000

[1] During the three months ended June 30, 2013, $1.4 million of share-based compensation expense was capitalized to inventory and $2.0 million of previously capitalized share-based compensation expenses in inventory was sold. 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 expense in inventory was sold.