Segment, Geographical and Other Revenue Information Segment Information As discussed in Note 2, "Basis of Presentation and Summary of Significant Accounting Policies," beginning in 2018, we identified our biotherapeutics business as a standalone business segment. Our two reportable business segments as of January 1, 2018, consisted of 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. In October 2017, we announced a strategic collaboration with Nestle Health Science to advance CDX-6114, our own novel orally administrable enzyme therapeutic candidate for the potential treatment of PKU disease. In July 2018, we announced that we had dosed the first subjects in a first-in-human Phase 1a dose-escalation trial with CDX-6114. On November 8, 2018, we announced top-line results from the Phase 1a study in healthy volunteers with CDX-6114. We have also developed a pipeline of other biotherapeutic drug candidates in which we expect to continue to make additional investments with the aim of advancing additional product candidates targeting other therapeutic areas. For the three and nine months ended September 30, 2018 , all revenues related to the Novel Biotherapeutics segment were generated from our collaboration with Nestle Health Science. There was no revenue related to the Novel Biotherapeutics segment for the three and nine months ended September 30, 2017 . Our CODM regularly reviews our segments and the approach provided by management for performance evaluation and resource allocation. In the second quarter of 2018, we made a change in the segment measurement for allocating operating expenses between our two reporting segments. The remaining expenses have been allocated to corporate costs. This change in measurement only impacts our segment disclosures, and it has no impact on our overall consolidated financial statements. We revised the allocation of operating expenses between the two segments based on better insight and improved judgment during the second quarter of 2018. 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. Management believes that the current allocation of research and development expenses provides a more accurate presentation of how the segments utilize research and development support activities as compared to the method previously used. This provides the CODM with more meaningful segment profitability reporting to support operating decisions and allocate resources. Following the change, we reclassified the research and development cost of $0.3 million from Performance Enzyme to Novel Biotherapeutics for the three months ended March 31, 2018 and we reclassified research and development cost of $0.1 million from Novel Biotherapeutics to Performance Enzyme for the three months ended March 31, 2017. Segment results for the three and nine months ended September 30, 2018 and 2017 have been revised to reflect this change in operating segment measurement. The following table provides financial information by our reportable business segments along with a reconciliation to consolidated loss before income taxes (in thousands): Three months ended September 30, 2018 Three months ended September 30, 2017 Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Revenues: Product revenue $ 8,405 $  $ 8,405 $ 6,948 $  $ 6,948 Research and development revenue 3,720 4,821 8,541 3,036  3,036 Total revenues 12,125 4,821 16,946 9,984  9,984 Costs and operating expenses: Cost of product revenue 3,791  3,791 3,976  3,976 Research and development (1) 4,758 2,920 7,678 4,410 3,474 7,884 Selling, general and administrative 1,870 165 2,035 1,649  1,649 Total segment costs and operating expenses 10,419 3,085 13,504 10,035 3,474 13,509 Income (loss) from operations $ 1,706 $ 1,736 $ 3,442 $ (51 ) $ (3,474 ) $ (3,525 ) Corporate costs (2) (5,120 ) (6,310 ) Depreciation (309 ) (241 ) Loss before income taxes $ (1,987 ) $ (10,076 ) (1) Research and development expenses exclude depreciation. (2) Corporate costs include unallocated selling, general and administrative expense, interest income, and other income and expenses. Nine months ended September 30, 2018 Nine months ended September 30, 2017 Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Revenues: Product revenue $ 18,291 $  $ 18,291 $ 19,134 $  $ 19,134 Research and development revenue 15,728 10,507 26,235 9,167  9,167 Total revenues 34,019 10,507 44,526 28,301  28,301 Costs and operating expenses: Cost of product revenue 10,228  10,228 10,768  10,768 Research and development (1) 14,548 7,294 21,842 12,582 7,134 19,716 Selling, general and administrative 5,695 615 6,310 5,238  5,238 Total segment costs and operating expenses 30,471 7,909 38,380 28,588 7,134 35,722 Income (loss) from operations $ 3,548 $ 2,598 $ 6,146 $ (287 ) $ (7,134 ) $ (7,421 ) Corporate costs (2) (15,762 ) (15,618 ) Depreciation (812 ) (795 ) Loss before income taxes $ (10,428 ) $ (23,834 ) (1) Research and development 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): Three months ended September 30, 2018 Three months ended September 30, 2017 Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Stock-based compensation $ 354 $ 97 $ 451 $ 607 $ 55 $ 662 Nine months ended September 30, 2018 Nine months ended September 30, 2017 Performance Enzymes Novel Biotherapeutics Total Performance Enzymes Novel Biotherapeutics Total Stock-based compensation $ 2,005 $ 243 $ 2,248 $ 1,670 $ 154 $ 1,824 Significant Customers Customers that each contributed 10% or more of our total revenues were as follows: Percentage of Total Revenues for the Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Customer A 27% 27% 33% 37% Customer B 28% * 24% * Customer C 10% 11% 17% 11% Customer D 15% 29% 11% 18% Customer E * 10% * * Customers that each contributed 10% or more of our total accounts receivable had the following balances as of the periods presented: Percentage of Accounts Receivables at September 30, 2018 December 31, 2017 Customer A 45% 31% Customer B 10% * Customer C * 16% Customer D 10% 15% Customer F * 14% Customer G 11% * * Less than 10% of the period presented Geographical Information Geographic revenues are identified by the location of the customer and consist of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Revenues Americas $ 4,315 $ 3,606 $ 13,968 $ 9,795 EMEA 6,274 3,415 15,075 8,581 APAC 6,357 2,963 15,483 9,925 Total revenues $ 16,946 $ 9,984 $ 44,526 $ 28,301 Identifiable long-lived assets as follows (in percentage): Long-lived assets: September 30, 2018 December 31, 2017 United States 100 % 100 %