The Company is organized and operates as one reportable segment, the design, development, manufacture and marketing of integrated circuits and related components for use primarily in the high-voltage power-conversion market. The Company’s chief operating decision maker, the Chief Executive Officer, reviews financial information presented on a consolidated basis for purposes of making operating decisions and assessing financial performance.

The Company’s top ten customers accounted for approximately 76% and 79% of net revenues for the three and nine months ended September 30, 2021, respectively, and approximately 65% and 56%, respectively in the corresponding periods of 2020. A significant portion of these revenues are attributable to sales of the Company’s products to distributors of electronic components. These distributors sell the Company’s products to a broad, diverse range of end users, including

original equipment manufacturers, or OEMs, and merchant power supply manufacturers. Sales to distributors were $127.3 million and $397.9 million in the three and nine months ended September 30, 2021, respectively, and $85.3 million and $256.1 million, respectively, for the corresponding periods of 2020. Direct sales to OEMs and power-supply manufacturers accounted for the remainder.

The following customers represented 10% or more of the Company’s net revenues for the respective periods:

*	Total customer revenue was less than 10% of net revenues.

No other customers accounted for 10% or more of the Company’s net revenues in the periods presented.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash investments and trade receivables. The Company does not have any off-balance-sheet credit exposure related to its customers. As of September 30, 2021, and December 31, 2020, 84% and 90%, respectively, of accounts receivable were concentrated with the Company’s top ten customers.

The following customers represented 10% or more of accounts receivable:


	September 30,		December 31,
Customer	2021		2020
Avnet	40	%	50	%
Powertech Distribution Ltd.	*		10	%

* Total customer accounts receivable was less than 10% of accounts receivable.

No other customers accounted for 10% or more of the Company’s accounts receivable in the periods presented.

Geographic Net Revenues

The Company markets its products globally through its sales personnel and a worldwide network of independent sales representatives and distributors. Geographic net revenues, based on “bill to” customer locations, for the three and nine months ended September 30, 2021 and 2020, were as follows:


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(In thousands)	2021		2020		2021		2020
United States of America	$	5,054	$	2,380	$	12,973	$	8,028
Hong Kong/China		103,937		76,549		344,790		202,642
Taiwan		7,629		4,133		20,432		17,811
Korea		17,508		12,121		43,702		29,762
Western Europe (excluding Germany)		11,418		7,535		27,268		25,565
Japan		6,959		4,303		16,758		12,606
Germany		9,402		5,755		24,064		17,169
Other		14,869		8,353		40,636		24,042
Total net revenues	$	176,776	$	121,129	$	530,623	$	337,625