9. Business segment information

The table below present net sales, which includes product sales and marketing service fees, by reporting segment:

	Three Months Ended June 30,
(U.S. Dollars, in thousands)	2018		2017		Change
BioStim	$	48,211	$	47,174		2.2	%
Spine Fixation		23,880		21,360		11.8	%
Biologics		14,668		15,661		-6.3	%
Extremity Fixation		24,788		24,747		0.2	%
Net sales	$	111,547	$	108,942		2.4	%

	Six Months Ended June 30,
(U.S. Dollars, in thousands)	2018		2017		Change
BioStim	$	94,374	$	91,713		2.9	%
Spine Fixation		44,587		40,627		9.7	%
Biologics		29,003		30,648		-5.4	%
Extremity Fixation		52,292		48,692		7.4	%
Net sales	$	220,256	$	211,680		4.1	%

The primary metric used in managing the Company is non-GAAP net margin, which is an internal metric that the Company defines as gross profit less sales and marketing expense. The table below presents non-GAAP net margin by reporting segment:

	Three Months Ended June 30,						Six Months Ended June 30,
(U.S. Dollars, in thousands)	2018			2017			2018			2017
BioStim	$	21,298		$	19,469		$	40,244		$	36,602
Spine Fixation		2,887			2,696			4,148			4,703
Biologics		6,247			6,470			12,327			12,641
Extremity Fixation		7,002			6,766			15,160			13,178
Corporate		(251	)		(107	)		(402	)		(205	)
Non-GAAP net margin	$	37,183		$	35,294		$	71,477		$	66,919
General and administrative		22,268			20,409			41,752			38,691
Research and development		7,891			6,887			14,828			14,311
Operating income	$	7,024		$	7,998		$	14,897		$	13,917
Interest income (expense), net		(251	)		76			(434	)		121
Other income (expense), net		(4,752	)		585			(1,840	)		(3,763	)
Income before income taxes	$	2,021		$	8,659		$	12,623		$	10,275

Geographical information

The table below present net sales by geographic destination for each reporting unit and for the consolidated Company:

	Three Months Ended June 30,				Six Months Ended June 30,
(U.S. Dollars, in thousands)	2018		2017		2018		2017
BioStim
U.S.	$	48,202	$	47,162	$	94,339	$	91,701
International		9		12		35		12
Total BioStim		48,211		47,174		94,374		91,713

Spine Fixation
U.S.		18,853		18,050		36,432		34,085
International		5,027		3,310		8,155		6,542
Total Spine Fixation		23,880		21,360		44,587		40,627

Biologics
U.S.		14,667		15,651		28,989		30,614
International		1		10		14		34
Total Biologics		14,668		15,661		29,003		30,648

Extremity Fixation
U.S.		7,023		6,741		13,939		13,320
International		17,765		18,006		38,353		35,372
Total Extremity Fixation		24,788		24,747		52,292		48,692

Consolidated
U.S.		88,745		87,604		173,699		169,720
International		22,802		21,338		46,557		41,960
Net sales	$	111,547	$	108,942	$	220,256	$	211,680