Goodwill and Intangible Assets, Net (Details 1) (USD $) In Thousands, unless otherwise specified	Sep. 29, 2013		Mar. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	$ 384,172		$ 384,172
Accumulated amortization	(344,130)		(335,570)
Net assets	40,042		48,602
Existing Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	241,197		241,197
Accumulated amortization	(208,940)		(203,129)
Net assets	32,257		38,068
Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	4,411		4,411
Accumulated amortization	(2,476)		(2,018)
Net assets	1,935		2,393
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	131,931		131,931
Accumulated amortization	(129,876)		(128,107)
Net assets	2,055		3,824
Order or Production Backlog [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	1,600		1,600
Accumulated amortization	(1,597)		(1,509)
Net assets	3		91
Noncompete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	2,600		2,600
Accumulated amortization	(1,241)		(807)
Net assets	1,359		1,793
Subtotal [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	381,739		381,739
Accumulated amortization	(344,130)		(335,570)
Net assets	37,609		46,169
In Process Research and Development [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	2,433	[1]	2,433	[1]
Accumulated amortization	0	[1]	0	[1]
Net assets	$ 2,433	[1]	$ 2,433	[1]

[1] IPR&D is initially capitalized at fair value as an intangible asset with an indefinite life and assessed for impairment thereafter. When the IPR&D project is complete, it is reclassified as an amortizable purchased intangible asset and is amortized over its estimated useful life. If an IPR&D project is abandoned, the Company will record a charge for the carrying value of the related intangible asset to its Consolidated Statements of Operations in the period it is abandoned.