Segment Information (Schedule Of Segment Revenue From Product Lines) (Details) (USD $) In Thousands	3 Months Ended	6 Months Ended
Sep. 24, 2011	Sep. 25, 2010	Sep. 24, 2011	Sep. 25, 2010
Product revenue	$ 101,602	$ 100,598	$ 193,844	$ 182,513
Audio Products [Member]
Product revenue	83,683	71,171	154,802	125,159
Energy Products [Member]
Product revenue	$ 17,919	$ 29,427	$ 39,042	$ 57,354

Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 1

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Name:	us-gaap_SalesRevenueGoodsNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration