CONDENSED CONSOLIDATED STATEMENTS OF INCOME (PARENTHETICAL) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2014		Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 11,901		$ 11,254
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	2,055	[1]	1,969	[1]
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	6,309		5,690
Selling General And Administrative Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 4,957		$ 4,997

[1] 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 expenses in inventory was sold. 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 expense in inventory was sold.