Segment, Geographical and Other Revenue Information Segment Information We manage our business as two business segments: Performance Enzymes and Novel Biotherapeutics. We report corporate-related expenses such as legal, accounting, information technology, and other costs that are not otherwise included in our reportable business segments as "Corporate costs." All items not included in income (loss) from operations are excluded from the business segments. We manage our assets on a total company basis, not by business segment, as the majority of our operating assets are shared or commingled. Our CODM does not review asset information by business segment in assessing performance or allocating resources, and accordingly, we do not report asset information by business segment. Performance Enzymes We initially commercialized our CodeEvolver  protein engineering technology platform and products in the pharmaceuticals market, and to date this continues to be our largest market served. Our customers, which include many large global pharmaceutical companies, use our technology, products and services in their manufacturing processes and process development. We have also used the technology to develop customized enzymes for use in other industrial markets. These markets consist of several large industrial verticals, including food and food ingredients, animal feed, flavors, fragrances, and agricultural chemicals. We also use our technology to develop enzymes for customers using NGS and PCR/qPCR for in vitro molecular diagnostic and molecular biology research applications. Novel Biotherapeutics We are also targeting new opportunities in the pharmaceutical industry to discover, improve, and/or develop biotherapeutic drug candidates. We believe that our CodeEvolver  protein engineering platform technology can be used to discover novel biotherapeutic drug candidates that will target human diseases that are in need of improved therapeutic interventions. Similarly, we believe that we can deploy our platform technology to improve specific characteristics of a customers pre-existing biotherapeutic drug candidate, such as its activity, stability or immunogenicity. Most notable is our lead program for the potential treatment of PKU in humans. PKU is an inherited metabolic disorder in which the enzyme that converts the essential amino acid phenylalanine into tyrosine is deficient. We have also developed a pipeline of other biotherapeutic drug candidates, which are in preclinical development, and in which we expect to continue to make additional investments with the aim of advancing additional product candidates targeting other therapeutic areas. Factors considered in determining the two reportable segments of the Company include the nature of business activities, the management structure directly accountable to our CODM for operating and administrative activities, availability of discrete financial information and information presented to the Board of Directors. Our CODM regularly reviews our segments and the approach provided by management for performance evaluation and resource allocation. Operating expenses that directly support the segment activity are allocated based on segment headcount, revenue contribution or activity of the business units within the segments, based on the corporate activity type provided to the segment. The expense allocation excludes certain corporate costs that are separately managed from the segments. This provides the CODM with more meaningful segment profitability reporting to support operating decisions and allocate resources. The following table provides financial information by our reportable business segments along with a reconciliation to consolidated loss before income taxes (in thousands): Year Ended December 31, 2019 Year Ended December 31, 2018 Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Revenues: Product revenue $ 29,465 $  $ 29,465 $ 25,590 $  $ 25,590 Research and development revenue 28,691 10,302 38,993 21,483 13,521 35,004 Total revenues 58,156 10,302 68,458 47,073 13,521 60,594 Costs and operating expenses: Cost of product revenue 15,632  15,632 12,620  12,620 Research and development (1) 19,380 13,278 32,658 18,924 10,185 29,109 Selling, general and administrative (1) 8,462 2,222 10,684 7,538 771 8,309 Total segment costs and operating expenses 43,474 15,500 58,974 39,082 10,956 50,038 Income (loss) from operations $ 14,682 $ (5,198) 9,484 $ 7,991 $ 2,565 10,556 Corporate costs (2) (19,624) (20,324) Depreciation and amortization (1,778) (1,147) Loss before income taxes $ (11,918) $ (10,915) (1) Research and development expenses and Selling, general and administrative expenses exclude depreciation and amortization of finance leases. (2) Corporate costs include unallocated selling, general and administrative expense, interest income, and other income and expenses. Year Ended December 31, 2018 Year Ended December 31, 2017 Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Revenues: Product revenue $ 25,590 $  $ 25,590 $ 26,685 $  $ 26,685 Research and development revenue 21,483 13,521 35,004 15,648 7,691 23,339 Total revenues 47,073 13,521 60,594 42,333 7,691 50,024 Costs and operating expenses: Cost of product revenue 12,620  12,620 14,327  14,327 Research and development (1) 18,924 10,185 29,109 16,847 12,107 28,954 Selling, general and administrative (1) 7,538 771 8,309 7,371  7,371 Total segment costs and operating expenses 39,082 10,956 50,038 38,545 12,107 50,652 Income (loss) from operations $ 7,991 $ 2,565 10,556 $ 3,788 $ (4,416) (628) Corporate costs (2) (20,324) (21,245) Depreciation (1,147) (1,042) Loss before income taxes $ (10,915) $ (22,915) (1) Research and development expenses and Selling, general and administrative expenses exclude depreciation. (2) Corporate costs include unallocated selling, general and administrative expense, interest income, and other income and expenses. The following table provides stock-based compensation expense included in income (loss) from operations by segment (in thousands): Year Ended December 31, 2019 Year Ended December 31, 2018 Year Ended December 31, 2017 Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Stock-based compensation $ 2,303 $ 695 $ 2,998 $ 2,591 $ 338 $ 2,929 $ 2,306 $ 208 $ 2,514 Stock-based compensation expense included in corporate services were $3.9 million, $5.0 million and $4.6 million for the years ended December 31, 2019, December 31, 2018 and December 31, 2017, respectively. Significant Customers Customers that each contributed 10% or more of our total revenues were as follows: Percentage of Total Revenues For The Years Ended December 31, 2019 2018 2017 Merck 28 % 29 % 28 % Novartis 23 % * 14 % Nestle Health Science 15 % 22 % 15 % Tate &amp; Lyle * 13 % 11 % * Percentage was less than 10% Customers that each accounted for 10% or more of our accounts receivable balance for the period presented were as follows: Percentage of Accounts Receivables As Of December 31, 2019 2018 Merck &amp; Co. 38 % 37 % Nestle Health Science 10 % 17 % Novartis * 11 % Kyorin Pharmaceutical Co Ltd * 16 % * Percentage was less than 10% Geographic Information Geographic revenues are identified by the location of the customer and consist of the following (in thousands): Year Ended December 31, 2019 2018 2017 Revenues Americas $ 13,039 $ 15,370 $ 15,575 EMEA 37,133 22,361 19,610 APAC 18,286 22,863 14,839 Total revenues $ 68,458 $ 60,594 $ 50,024 Identifiable long-lived assets by location and goodwill by reporting unit as of year-end were as follows (in thousands): December 31, 2019 2018 Long-lived assets United States $ 6,282 $ 4,759 Year Ended December 31, 2019 Year Ended December 31, 2018 Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Goodwill $ 2,463 $ 778 $ 3,241 $ 2,463 $ 778 $ 3,241