Segment Information (Details) (USD $) In Thousands	3 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Segment reporting information [Line Items]
Net sales	$ 374,507	$ 357,125
Gross Profit	219,748	207,443
Semiconductor products [Member]
Segment reporting information [Line Items]
Net sales	353,860	341,768
Gross Profit	200,065	193,104
Technology licensing [Member]
Segment reporting information [Line Items]
Net sales	20,647	15,357
Gross Profit	$ 19,683	$ 14,339

Amount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 131
-Paragraph 27
-Subparagraph a, b, c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a),(b),(c)
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599

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