CONCENTRATION OF RISK

6 Months Ended

Jun. 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 June 30,		% of Total Revenue for the Six Months Ended June 30,		Accounts Receivable as of
Customer	2021	2020	2021	2020	June 30, 2021
A	51%	28%	43%	36%	$	15,619
B	26%	34%	24%	28%	$	38,101
C	15%	13%	18%	19%	$	5,955

Revenues from outside of North America represented approximately 97% and 93% of consolidated revenue for the three months ended June 30, 2021 and 2020, respectively, and approximately 97% and 96% for the six months ended June 30, 2021 and 2020, respectively. Revenues by geographic area are as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
Country	2021		2020		2021		2020
South Korea	$	86,324	$	31,062	$	154,299	$	100,487
China		36,308		20,508		96,812		58,342
Japan		2,001		2,197		3,316		3,984
Other non-U.S. locations		895		315		1,720		812
Total non-U.S. locations		125,528		54,082		256,147		163,625
United States		4,132		3,886		7,513		6,620
Total revenue	$	129,660	$	57,968	$	263,660	$	170,245

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):

	June 30, 2021		December 31, 2020
United States	$	104,692	$	93,230
Other		8,495		8,883
Total long-lived assets	$	113,187	$	102,113

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