CONCENTRATION OF RISK

9 Months Ended

Sep. 30, 2021

16. CONCENTRATION OF RISK:

Revenues and accounts receivable from the Company's largest customers were as follows (in thousands):


	% of Total Revenue for the Three Months Ended September 30,		% of Total Revenue for the Nine Months Ended September 30,		Accounts Receivable as of
Customer	2021	2020	2021	2020	September 30, 2021
A	50%	41%	46%	38%	$	10,129
B	27%	28%	25%	28%	$	23,786
C	7%	14%	14%	17%	$	33,520

Revenues from outside of North America represented approximately 97% of consolidated revenue for both three-month periods ended September 30, 2021 and 2020, and approximately 97% and 96% for the nine months ended September 30, 2021 and 2020, respectively. Revenues by geographic area are as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
Country	2021		2020		2021		2020
South Korea	$	95,741	$	66,667	$	250,040	$	167,154
China		41,323		43,569		138,135		101,911
Japan		1,911		2,279		5,227		6,263
Other non-U.S. locations		537		663		2,257		1,475
Total non-U.S. locations		139,512		113,178		395,659		276,803
United States		4,106		3,901		11,619		10,521
Total revenue	$	143,618	$	117,079	$	407,278	$	287,324

The Company attributes revenue to different geographic areas on the basis of the location of the customer.

Long-lived assets (net), by geographic area are as follows (in thousands):


	September 30, 2021		December 31, 2020
United States	$	109,461	$	93,230
Other		9,527		8,883
Total long-lived assets	$	118,988	$	102,113

Substantially all chemical materials were purchased from one supplier. See Note 10.