CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Mar. 31, 2011
Income Statement
Net sales	$ 1,581,623		$ 1,383,176		$ 1,487,205
Cost of sales	743,164	[1]	583,882	[1]	605,954	[1]
Gross profit	838,459		799,294		881,251
Operating expenses:
Research and development	254,723	[1]	182,650	[1]	170,607	[1]
Selling, general and administrative	261,471	[1]	208,328	[1]	222,184	[1]
Amortization of acquired intangible assets	111,537		10,963		12,412
Special charges, net	32,175		837		1,865
Total operating expenses	659,906		402,778		407,068
Operating income	178,553		396,516		474,183
(Losses) gains on equity method investments	(617)		(195)		157
Other income (expense):
Interest income	15,560		17,992		16,002
Interest expense	(40,915)		(34,266)		(31,521)
Other (expense) income, net	(404)		(352)		1,877
Income from continuing operations before income taxes	152,177		379,695		460,698
Income tax provision	24,788		42,990		31,531
Net income from continuing operations	127,389		336,705		429,167
Discontinued operations:
Loss from discontinued operations before income taxes	0		0		(11,126)
Income tax benefit	0		0		(909)
Net loss from discontinued operations	0		0		(10,217)
Net income	$ 127,389		$ 336,705		$ 418,950
Basic net income per common share - continuing operations	$ 0.65		$ 1.76		$ 2.29
Basic net loss per common share - discontinued operations	$ 0.00		$ 0.00		$ (0.05)
Basic net income per common share	$ 0.65		$ 1.76		$ 2.24
Diluted net income per common share - continuing operations	$ 0.62		$ 1.65		$ 2.20
Diluted net loss per common share - discontinued operations	$ 0.00		$ 0.00		$ (0.05)
Diluted net income per common share	$ 0.62		$ 1.65		$ 2.15
Dividends declared per common share	$ 1.406		$ 1.390		$ 1.374
Basic common shares outstanding	194,595		191,283		187,066
Diluted common shares outstanding	205,776		203,519		194,715

[1] Includes share-based compensation expense as follows:Cost of sales 8,234 5,648 6,825Research and development 22,178 14,719 12,874Selling, general and administrative 27,603 17,922 17,113