Note 13. Segment, Geographic, Product and Significant Customer Information

The Company has one operating segment, which is the sale, design, manufacture, marketing and support of optical critical dimension and thin film systems. The following tables summarize total net revenues and long-lived assets (excluding intangible assets) attributed to significant countries (in thousands):

	Three Months Ended				Nine Months Ended
	September 29, 2018		September 30, 2017		September 29, 2018		September 30, 2017
Total net revenues:
South Korea	$	23,598	$	22,269	$	92,397	$	72,388
Japan		19,693		4,781		48,090		17,400
United States		8,414		6,231		22,545		28,101
China		14,486		3,403		50,861		17,420
Taiwan		1,883		2,304		4,918		19,016
Singapore		5,842		9,774		20,377		12,229
Other		2,674		7,913		8,319		13,862
Total net revenues	$	76,590	$	56,675	$	247,507	$	180,416

	September 29, 2018		December 30, 2017
Long-lived tangible assets:
United States	$	42,013	$	43,427
International		1,122		1,383
Total long-lived tangible assets	$	43,135	$	44,810

With respect to customer concentration, Samsung Electronics Co. Ltd., Yangtze Memory Technologies Co. Ltd., SK Hynix, and Toshiba Corporation each accounted for more than 10% of total sales for the three months ended September 29, 2018, and Samsung Electronics Co. Ltd., SK Hynix, Toshiba Corporation, Yangtze Memory Technologies Co. Ltd., and Micron Technology, Inc. each accounted for more than 10% of total sales for the nine months ended September 29, 2018. Samsung Electronics Co. Ltd., Intel Corporation, and Micron Technology, Inc. each accounted for more than 10% of total sales for the three months ended September 30, 2017, and Samsung Electronics Co. Ltd., SK Hynix, Intel Corporation, and Micron Technology, Inc. each accounted for more than 10% of total sales for the nine months ended September 30, 2017.

With respect to accounts receivable concentration, Toshiba Corporation and SK Hynix each accounted for more than 10% of total accounts receivable as of September 29, 2018. Samsung Electronics Co. Ltd., Micron Technology, Inc., and Intel Corporation each accounted for more than 10% of total accounts receivable as of December 30, 2017.