CONCENTRATION OF RISK

12 Months Ended

Dec. 31, 2022

19.

CONCENTRATION OF RISK:

Revenues and accounts receivable from the Company's largest customers for the years ended December 31, 2022, 2021 and 2020 were as follows (in thousands):


	2022			2021			2020
Customer	% of Total Revenue	Accounts Receivable		% of Total Revenue	Accounts Receivable		% of Total Revenue	Accounts Receivable
A	41%	$	11,425	44%	$	10,850	41%	$	20,476
B	25%		24,440	26%		45,867	30%		26,776
C	16%		22,291	14%		18,557	13%		2,757

Revenues from outside of North America represented approximately 97% of consolidated revenue for each of the years ended December 31, 2022, 2021 and 2020. Revenues by geographic area are as follows (in thousands):


	Year Ended December 31,
Country	2022		2021		2020
South Korea	$	360,640	$	334,835	$	263,079
China		230,582		192,079		142,076
Japan		5,579		7,358		7,405
Other non-U.S. locations		3,829		3,137		1,728
Total non-U.S. locations		600,630		537,409		414,288
United States		15,989		16,116		14,579
Total revenue	$	616,619	$	553,525	$	428,867

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):


	December 31,
Country	2022		2021
United States	$	117,255	$	115,004
Ireland		20,270		7,000
Other		5,920		6,828
Total long-lived assets	$	143,445	$	128,832

Substantially all chemical materials were purchased from one supplier. See Note 13.