Note 15 - Segment and Geographic Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Net Revenues	$ 79,484	$ 75,133	$ 238,751	$ 237,437
Power Semiconductors [Member]
Net Revenues	54,647	51,196	164,663	159,607
Integrated Circuits [Member]
Net Revenues	20,032	18,749	60,967	63,257
Systems and RF Power Semiconductors [Member]
Net Revenues	$ 4,805	$ 5,188	$ 13,121	$ 14,573