Note 6 - Segment Information (Detail) - Revenue By Region (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011		Sep. 30, 2012	Sep. 30, 2011
Revenue By Region	$ 56,508	$ 52,962	[1]	$ 165,599	$ 149,058	[1]
China [Member]
Revenue By Region	31,023	32,480		95,207	87,360
Taiwan [Member]
Revenue By Region	7,579	6,110		21,814	16,395
Korea [Member]
Revenue By Region	3,022	2,754		7,581	11,598
Europe [Member]
Revenue By Region	5,004	3,736		12,987	10,778
Japan [Member]
Revenue By Region	2,029	2,475		6,690	8,193
United States [Member]
Revenue By Region	1,437	1,230		4,150	3,196
Other Region [Member]
Revenue By Region	$ 6,414	$ 4,177		$ 17,170	$ 11,538

[1] * 2011 Revenue associated with Audio Amplifiers has been included with DC to DC Converters to conform with current year presentation.