The Company views its operations, makes decisions regarding how to allocate resources and manages its business as one operating segment. As a result, the financial information disclosed herein represents all of the material financial information related to the Company’s sole operating segment.

Revenue from filtration products includes our XCell ATF Systems and consumables as well as our KrosFlo and SIUS filtration products. Revenue from chromatography products includes our OPUS and OPUS PD chromatography columns, chromatography resins and ELISA test kits. Revenue from protein products includes our Protein A ligands and cell culture growth factors. Revenue from our process analytics products includes the sale of our SoloVPE and FlowVPE systems and consumables. Other revenue primarily consists of revenue from the sale of operating room products to hospitals as well as freight revenue.

The following table represents the Company’s total revenue by geographic area (based on the location of the customer):


	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2019			2018			2019			2018
Revenue by customers’ geographic locations:
North America		51	%		47	%		49	%		46	%
Europe		38	%		41	%		39	%		42	%
APAC		11	%		12	%		12	%		12	%

Total revenue		100	%		100	%		100	%		100	%

Concentrations of Credit Risk and Significant Customers

Financial instruments that subject the Company to significant concentrations of credit risk primarily consist of cash and cash equivalents, marketable securities and accounts receivable. Per the Company’s investment policy, cash equivalents and marketable securities are invested in financial instruments with high credit ratings and credit exposure to any one issue, issuer (with the exception of U.S. treasury obligations) and type of instrument is limited. At June 30, 2019 and December 31, 2018, the Company had no investments associated with foreign exchange contracts, options contracts or other foreign hedging arrangements.

Concentration of credit risk with respect to accounts receivable is limited to customers to whom the Company makes significant sales. While a reserve for the potential

write-off

of accounts receivable is maintained, the Company has not written off any significant accounts to date. To control credit risk, the Company performs regular credit evaluations of its customers’ financial condition.

Revenue from significant customers as a percentage of the Company’s total revenue is as follows:


	Three Months Ended June 30,						Six Months Ended June 30,
	2019			2018			2019			2018
GE Healthcare		16	%		14	%		14	%		16	%
MilliporeSigma		13	%		18	%		14	%		17	%

Significant accounts receivable balances as a percentage of the Company’s total trade accounts receivable are as follows:


	June 30,			December 31,
	2019			2018
GE Healthcare		18	%		17	%
MilliporeSigma		10	%		11	%