Note 15 Segment and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net Revenues	$ 89,348	$ 63,812	$ 246,435	$ 213,130
Power Semiconductors [Member]
Segment Reporting Information [Line Items]
Net Revenues	52,688	45,011	164,074	152,796
Integrated Circuits [Member]
Segment Reporting Information [Line Items]
Net Revenues	31,155	13,401	65,755	44,100
System and RF Power Semiconductors [Member]
Segment Reporting Information [Line Items]
Net Revenues	5,505	5,400	16,606	16,234
United States [Member]
Segment Reporting Information [Line Items]
Net Revenues	21,959	19,431	66,043	64,594
France [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,097	1,138	3,729	3,836
Germany [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	7,376	7,433	24,538	24,036
Italy [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,280	798	3,274	2,729
Sweden [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,142	1,115	3,810	3,540
Switzerland [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	919	952	3,033	2,603
United Kingdom [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	4,177	5,465	14,924	19,018
China [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	27,631	9,699	62,572	33,669
Japan [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,238	1,348	4,644	4,893
Korea [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	5,503	1,746	12,807	6,071
Malaysia [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	881	1,108	2,504	3,557
Singapore [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	3,048	2,287	8,792	7,441
India [Member] | Rest Of World [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,147	1,251	3,694	4,523
Other Geographic Regions [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	6,943	6,154	20,125	19,624
Other Geographic Regions [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	2,631	2,235	6,720	7,386
Other Geographic Regions [Member] | Rest Of World [Member]
Segment Reporting Information [Line Items]
Net Revenues	$ 2,376	$ 1,652	$ 5,226	$ 5,610