CONDENSED CONSOLIDATED STATEMENTS OF INCOME (PARENTHETICAL) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2013		Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 12,209		$ 11,365		$ 36,874		$ 37,163
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	1,841	[1]	1,834	[1]	5,674	[1]	5,758	[1]
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	6,141		6,172		18,762		16,562
Selling General And Administrative Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 5,737		$ 6,114		$ 16,939		$ 22,339

[1] During the three and nine months ended December 31, 2013, $1.9 million and $5.7 million, respectively, of share-based compensation expense was capitalized to inventory and $1.8 million and $5.7 million, respectively, of previously capitalized share-based compensation expenses in inventory was sold. During the three and nine months ended December 31, 2012, $1.8 million and $5.3 million, respectively, of share-based compensation expense was capitalized to inventory and $1.8 million and $5.8 million, respectively, of previously capitalized share-based compensation expense in inventory was sold.