Note 8 - Segment and Geographic Information (Tables)

9 Months Ended

Sep. 30, 2019

Notes Tables

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

	Revenue												Accounts Receivable
	Three Months Ended September 30,						Nine Months Ended September 30,						September 30,			December 31,
Customer	2019			2018			2019			2018			2019			2018
Company A (distributor)		24	%		23	%		23	%		21	%		25	%		25	%
Company B (distributor)		*			10	%		*			10	%		12	%		16	%
Company A (value-added reseller)		*			*			*			*			10	%		*

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
Country or Region	2019		2018		2019		2018
China	$	105,857	$	91,509	$	276,892	$	245,580
Taiwan		18,547		20,774		55,912		55,315
Europe		12,047		12,579		38,071		36,696
Korea		11,990		11,406		31,224		30,046
Southeast Asia		7,904		11,259		23,698		28,261
Japan		8,150		6,895		21,084		18,994
United States		4,225		5,375		14,044		13,404
Other		93		178		258		589
Total	$	168,813	$	159,975	$	461,183	$	428,885

Revenue from External Customers by Products and Services [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
Product Family	2019		2018		2019		2018
DC to DC	$	159,723	$	147,727	$	432,125	$	394,492
Lighting Control		9,090		12,248		29,058		34,393
Total	$	168,813	$	159,975	$	461,183	$	428,885

Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country [Table Text Block]

	September 30,		December 31,
Country	2019		2018
China	$	105,030	$	93,096
United States		93,967		39,054
Taiwan		16,750		16,972
Other		1,296		879
Total	$	217,043	$	150,001