Note 14 Segment and Geographic Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net Revenues	$ 81,326	$ 89,348	$ 255,841	$ 246,435
Power Semiconductors [Member]
Segment Reporting Information [Line Items]
Net Revenues	52,245	52,688	165,993	164,074
Integrated Circuits [Member]
Segment Reporting Information [Line Items]
Net Revenues	23,484	31,155	70,804	65,755
System and RF Power Semiconductors [Member]
Segment Reporting Information [Line Items]
Net Revenues	5,597	5,505	19,044	16,606
United States [Member]
Segment Reporting Information [Line Items]
Net Revenues	20,506	21,959	64,512	66,043
France [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	2,208	1,097	5,957	3,729
Germany [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	7,720	7,376	24,195	24,538
Italy [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,189	1,280	3,571	3,274
Russia [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,621	717	4,482	2,096
Sweden [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,138	1,142	3,732	3,810
United Kingdom [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	4,752	4,177	15,953	14,924
China [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	20,949	27,631	61,831	62,572
Japan [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,675	1,238	5,637	4,644
Korea [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	4,661	5,503	16,789	12,807
Malaysia [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,197	881	4,319	2,504
Singapore [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	2,753	3,048	8,823	8,792
India [Member] | Rest Of World [Member]
Segment Reporting Information [Line Items]
Net Revenues	1,150	1,147	3,779	3,694
Other Geographic Regions [Member] | Europe and Middle East [Member]
Segment Reporting Information [Line Items]
Net Revenues	6,020	7,145	19,913	21,062
Other Geographic Regions [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net Revenues	2,671	2,631	8,514	6,720
Other Geographic Regions [Member] | Rest Of World [Member]
Segment Reporting Information [Line Items]
Net Revenues	$ 1,116	$ 2,376	$ 3,834	$ 5,226