The Company has one operating segment, which is the sale, design, manufacture, marketing and support of thin film and optical critical dimension systems. The Chief Executive Officer has been identified as the Chief Operating Decision Maker (“CODM”) because he has the final authority over resource allocation decisions and performance assessment. The CODM does not receive discrete financial information about individual components of the Company's business. For the years ended December 29, 2018, December 30, 2017, and December 26, 2016, the Company recorded revenue from customers primarily in the United States, Asia and Europe. The following tables summarize total net revenues and long-lived assets (excluding intangible assets) attributed to significant countries (in thousands):

	Years Ended
	December 29, 2018		December 30, 2017		December 31, 2016
Total net revenues^(1):
South Korea	$	108,938	$	94,082	$	44,735
China		72,305		29,826		43,460
Japan		64,252		41,979		26,604
United States		29,415		33,983		29,887
Singapore		22,167		21,810		37,096
Taiwan		14,012		20,147		27,189
Other		13,434		16,794		12,158
Total net revenues	$	324,523	$	258,621	$	221,129

⁽¹⁾	Net revenues are attributed to countries based on the customer's deployment and service locations of systems.

	Years Ended
	December 29, 2018		December 30, 2017
Long-lived tangible assets:
United States	$	46,325	$	43,427
Taiwan		275		510
South Korea		420		576
Japan		59		60
Singapore		618		92
All Other		203		145
Total long-lived tangible assets	$	47,900	$	44,810

With respect to customer concentration, Samsung Electronics Co. Ltd., SK hynix, Toshiba Corporation, and Intel Corporation each accounted for more than 10% of total sales for the year ended December 29, 2018, and Samsung Electronics Co. Ltd., SK hynix, Micron Technology, Inc., Intel Corporation, and Toshiba Corporation each accounted for more than 10% of total sales for the year ended December 30, 2017, and Micron Technology, Inc., Intel Corporation, SK hynix, and Taiwan Semiconductor Manufacturing Company Limited each accounted for more than 10% of total sales for the year ended December 31, 2016.

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