Employee Benefit Plans (Details 2) (USD $)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Share-based compensation expense and related tax benefit
Total share-based compensation expense	$ 25,546,000	$ 25,198,000	$ 31,529,000
Income tax benefit	(4,902,000)	(5,356,000)	(6,294,000)
Total share-based compensation expense, net of income tax	20,644,000	19,842,000	25,235,000
Share-based compensation expenses capitalized as inventory	400,000	400,000	700,000
Cost of goods sold
Share-based compensation expense and related tax benefit
Total share-based compensation expense	2,518,000	2,499,000	3,620,000
Research and development
Share-based compensation expense and related tax benefit
Total share-based compensation expense	4,546,000	7,532,000	7,187,000
Marketing and selling
Share-based compensation expense and related tax benefit
Total share-based compensation expense	8,298,000	7,825,000	12,716,000
General and administrative
Share-based compensation expense and related tax benefit
Total share-based compensation expense	$ 10,184,000	$ 7,342,000	$ 8,006,000