CONDENSED CONSOLIDATED STATEMENTS OF INCOME (PARENTHETICAL) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 13,440		$ 13,411		$ 25,341		$ 24,665
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	2,640	[1]	1,864	[1]	4,695	[1]	3,833	[1]
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	7,261		6,931		13,570		12,621
Selling General And Administrative Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 5,372		$ 6,205		$ 10,329		$ 11,202

[1] During the three and six months ended September 30, 2014, $1.6 million and $3.3 million, respectively, of share-based compensation expense was capitalized to inventory and $2.6 million and $4.7 million, respectively, of previously capitalized share-based compensation expenses in inventory was sold. During the three and six months ended September 30, 2013, $2.4 million and $3.8 million, respectively, of share-based compensation expense was capitalized to inventory and $1.9 million and $3.8 million, respectively, of previously capitalized share-based compensation expense in inventory was sold.