Note 13 - Segment and Geographic Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Power Semiconductors [Member]
Net Revenues	$ 53,433	$ 55,780	$ 108,411	$ 113,748
Integrated Circuits [Member]
Net Revenues	22,024	23,438	44,508	47,320
Systems and RF Power Semiconductors [Member]
Net Revenues	4,800	7,217	9,385	13,447
Net Revenues	$ 80,257	$ 86,435	$ 162,304	$ 174,515