CONCENTRATION OF RISK (Tables)

12 Months Ended

Dec. 31, 2020

Risks And Uncertainties [Abstract]

Revenues and Accounts Receivable From Our Largest Customers

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

	2020			2019			2018
Customer	% of Total Revenue	Accounts Receivable		% of Total Revenue	Accounts Receivable		% of Total Revenue	Accounts Receivable
A	41%	$	20,476	44%	$	13,830	37%	$	14,419
B	30%		26,776	27%		19,346	33%		11,990
C	13%		2,757	15%		10,592	10%		9,071

Revenues by Geographic Area

Revenues by geographic area are as follows (in thousands):

	Year Ended December 31,
Country	2020		2019		2018
South Korea	$	263,079	$	250,562	$	171,915
China		142,076		135,259		51,931
Japan		7,405		5,276		6,823
Other non-U.S. locations		1,728		2,270		2,967
Total non-U.S. locations		414,288		393,367		233,636
United States		14,579		11,810		13,778
Total revenue	$	428,867	$	405,177	$	247,414

Long-Lived Assets (Net) by Geographic Area

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

	2020		2019
United States	$	93,230	$	80,027
Other		8,883		7,845
Total long-lived assets	$	102,113	$	87,872