Note 7 - Segment, Significant Customers and Geographic Information (Tables)

6 Months Ended

Jun. 30, 2020

Notes Tables

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

	Revenue												Accounts Receivable
	Three Months Ended June 30,						Six Months Ended June 30,						June 30,			December 31,
Customer	2020			2019			2020			2019			2020			2019
Distributor A		26	%		22	%		24	%		22	%		27	%		24	%
Distributor B		*			*			*			*			*			11	%
Value-added reseller A		*			*			*			*			19	%		13	%
Direct customer A		*			13	%		*			10	%		*			*

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

	Three Months Ended June 30,				Six Months Ended June 30,
Country or Region	2020		2019		2020		2019
China	$	112,756	$	94,837	$	218,493	$	171,035
Taiwan		22,322		16,018		38,862		37,365
Europe		13,443		13,040		26,515		26,024
South Korea		12,573		9,623		23,517		19,234
Southeast Asia		11,622		7,122		20,402		15,794
Japan		8,756		6,292		15,646		12,934
United States		4,681		4,013		8,418		9,819
Other		56		62		134		165
Total	$	186,209	$	151,007	$	351,987	$	292,370

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

	Three Months Ended June 30,				Six Months Ended June 30,
Product Family	2020		2019		2020		2019
DC to DC	$	176,113	$	139,691	$	332,988	$	272,402
Lighting Control		10,096		11,316		18,999		19,968
Total	$	186,209	$	151,007	$	351,987	$	292,370

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

	June 30,		December 31,
Country	2020		2019
China	$	129,700	$	113,888
United States		100,716		94,671
Taiwan		17,808		17,652
Other		3,756		2,104
Total	$	251,980	$	228,315