Note 11. Segment Information and Foreign Operations

Segment Information

We operate in one segment for the design, development, manufacture and distribution of high-performance compound and single element semiconductor substrates and sale of raw materials integral to these substrates. In accordance with ASC Topic 280, Segment Reporting, our chief operating decision-maker has been identified as our Chief Executive Officer, who reviews operating results to make decisions about allocating resources and assessing performance for the Company. Since we operate in one segment, all financial segment and product line information can be found in the condensed consolidated financial statements.

Product Information

The following table represents revenue amounts (in thousands) by product type:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2019		2018		2019		2018
Product Type:
Substrates	$	20,599	$	21,603	$	37,365	$	40,967
Raw Materials and Other		4,198		5,517		7,640		10,572
Total	$	24,797	$	27,120	$	45,005	$	51,539

Geographical Information

The following table represents revenue amounts (in thousands) reported for products shipped to customers in the corresponding geographic region:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2019		2018		2019		2018
Geographical region:
China	$	9,642	$	8,820	$	16,753	$	16,003
Taiwan		4,655		4,280		7,663		9,329
Europe (primarily Germany)		4,640		6,685		9,015		13,078
Asia Pacific (excluding China, Taiwan and Japan)		2,738		2,571		3,922		4,065
North America (primarily the United States)		1,612		2,240		4,350		4,085
Japan		1,510		2,524		3,302		4,979
Total	$	24,797	$	27,120	$	45,005	$	51,539

Long-lived assets consist primarily of property, plant and equipment and operating lease right-of-use assets, and are attributed to the geographic location in which they are located. Long-lived assets, net of depreciation, by geographic region were as follows (in thousands):


	As of
	June 30,		December 31,
	2019		2018
Long-lived assets by geographic region, net of depreciation:
North America	$	1,094	$	445
China		87,505		81,835
	$	88,599	$	82,280

Significant Customers

Two customers, Haisi Optoelectronics and Landmark, represented 18% and 15%, respectively, of our revenue for the three months ended June 30, 2019 while no customer represented more than 10% of our revenue for the three months ended June 30, 2018. Our top five customers, although not the same five customers for each period, represented 48% and 33% of our revenue for the three months ended June 30, 2019 and 2018, respectively.

Two customers, Haisi Optoelectronics and Landmark, represented 15% and 13%, respectively, of our revenue for the six months ended June 30, 2019 while two customers, Osram Opto and Landmark, represented 11% and 10%, respectively, of our revenue for the six months ended June 30, 2018. Our top five customers, although not the same five customers for each period, represented 43% and 35% of our revenue for the six months ended June 30, 2019 and 2018, respectively.

We perform ongoing credit evaluations of our customers’ financial condition, and limit the amount of credit extended when deemed necessary, but generally do not require collateral. Three customers accounted for 14%, 11% and 10% of our accounts receivable balance as of June 30, 2019, and three customers accounted for 17%, 12% and 10% of our accounts receivable as of December 31, 2018.