Note 14 - Segment and Geographic Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Power Semiconductors [Member]
Net Revenues	$ 53,537	$ 53,433	$ 110,016	$ 108,411
Integrated Circuits [Member]
Net Revenues	20,553	22,024	40,935	44,508
Systems and RF Power Semiconductors [Member]
Net Revenues	4,539	4,800	8,316	9,385
Net Revenues	$ 78,629	$ 80,257	$ 159,267	$ 162,304