Share-Based Compensation (Details) - USD ($) $ in Thousands		3 Months Ended
		Jun. 30, 2015	Jun. 30, 2014
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense		$ 14,112	$ 13,321
Income tax benefit		3,532	1,420
Net income effect of share-based compensation		10,580	11,901
Inventory [Member]
Stock-based compensation expense [Line Items]
Amount of share-based compensation expense capitalized to inventory		1,800	1,700
Cost of Sales [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense	[1]	1,657	2,055
Research and development [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense		7,098	6,309
Selling, General and Administrative Expenses [Member]
Stock-based compensation expense [Line Items]
Allocated Share-based Compensation Expense		$ 5,357	$ 4,957

[1] During the three months ended June 30, 2015, $1.8 million of share-based compensation expense was capitalized to inventory and $1.7 million of previously capitalized share-based compensation expense in inventory was sold. During the three months ended June 30, 2014, $1.7 million of share-based compensation expense was capitalized to inventory and $2.1 million of previously capitalized share-based compensation expense in inventory was sold.