CONDENSED CONSOLIDATED STATEMENTS OF INCOME (PARENTHETICAL) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2012		Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 11,365		$ 8,701		$ 37,163		$ 24,815
Cost of Sales [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	1,834	[1]	1,369	[1]	5,758	[1]	4,376	[1]
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	6,172		3,851		16,562		10,820
Selling General And Administrative Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 6,114		$ 4,742		$ 22,339		$ 13,274

[1] 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 expenses in inventory was sold. During the three and nine months ended December 31, 2011, $1.7 million and $4.9 million, respectively, of share-based compensation expense was capitalized to inventory and $1.4 million and $4.4 million, respectively, of previously capitalized share-based compensation expense in inventory was sold.