SEGMENT REPORTING

The Company's two reportable segments are CCA and OVP. The CCA segment includes Point of Care diagnostic laboratory instruments and consumables, and Point of Care digital imaging diagnostic instruments and software services as well as single use diagnostic and other tests, pharmaceuticals and vaccines, primarily for canine and feline use. These products are sold directly by the Company as well as through independent third party distributors and through other distribution relationships. CCA segment products manufactured at the Des Moines, Iowa production facility included in the OVP segment's assets are transferred at cost and are not recorded as revenue for the OVP segment. The OVP segment includes private label vaccine and pharmaceutical production, primarily for cattle, in addition to other small mammals. All OVP products are sold by third parties under third party labels.

Summarized financial information concerning the Company's reportable segments is shown in the following tables (in thousands):



Year Ended December 31, 2019	Core Companion Animal			Other Vaccines and Pharmaceuticals			Total
Total revenue	$	106,570		$	16,091		$	122,661
Operating income (loss)	1,358			(1,031		)	327
(Loss) income before income taxes	(1,552		)	(1,031		)	(2,583		)
Investments in unconsolidated affiliates	7,424			—			7,424
Total assets	223,980			20,444			244,424
Net assets	137,072			17,292			154,364
Capital expenditures	259			785			1,044
Depreciation and amortization	3,611			1,305			4,916



Year Ended December 31, 2018	Core Companion Animal		Other Vaccines and Pharmaceuticals		Total
Total revenue	$	108,924	$	18,522	$	127,446
Operating income	2,040		1,754		3,794
Income before income taxes	2,053		1,754		3,807
Investments in unconsolidated affiliates	8,018		—		8,018
Total assets	133,586		22,866		156,452
Net assets	96,129		26,280		122,409
Capital expenditures	180		1,178		1,358
Depreciation and amortization	3,369		1,226		4,595



Year Ended December 31, 2017	Core Companion Animal		Other Vaccines and Pharmaceuticals		Total
Total revenue	$	105,191	$	24,150	$	129,341
Operating income	12,656		5,563		18,219
Income before income taxes	12,828		5,541		18,369
Investments in unconsolidated affiliates	—		—		—
Total assets	111,625		23,819		135,444
Net assets	75,984		24,456		100,440
Capital expenditures	209		3,260		3,469
Depreciation and amortization	3,736		1,018		4,754

Revenue is attributed to individual countries based on customer location. Total revenue by principal geographic area was as follows (in thousands):



	For the Years Ended December 31,
	2019		2018		2017
U.S.	$	108,469	$	115,543	$	116,823
Canada	3,042		2,992		2,924
Europe	8,289		5,995		4,780
Other International	2,861		2,916		4,814
Total	$	122,661	$	127,446	$	129,341

Total long-lived assets by principal geographic areas were as follows (in thousands):



	As of December 31,
	2019		2018		2017
U.S.	$	14,712	$	15,933	$	17,288
Europe	576		37		18
Other International	181		11		25
Total	$	15,469	$	15,981	$	17,331

In our CCA segment, revenue from Covetrus represented approximately 14%, 15% and 13% of our consolidated revenue for the years ended December 31, 2019, 2018 and 2017, respectively. Revenue from Merck entities, including Merck Animal Health, represented approximately 1%, 12% and 12% for the years ended December 31, 2019, 2018 and 2017, respectively. In our OVP segment, revenue from Elanco represented approximately 8%, 9% and 11% for the years ended December 31, 2019, 2018 and 2017, respectively. No other customer accounted for more than 10% of our consolidated revenue for the years ended December 31, 2019, 2018 or 2017.