Note 15 - Segment and Geographic Information - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Net Revenues	$ 83,372	$ 79,484	$ 78,629	$ 80,638	$ 79,772	$ 75,133	$ 80,257	$ 82,047	$ 322,123	$ 317,209	$ 338,767
Power Semiconductors [Member]
Net Revenues									221,312	213,347	219,445
Integrated Circuits [Member]
Net Revenues									82,067	84,078	95,547
Systems and RF Power Semiconductors [Member]
Net Revenues									$ 18,744	$ 19,784	$ 23,775