Following theSpin-Off, our company has remained responsible for its own research and development efforts. Cerence employees who have been engaged in research and development attributable to Cerence have generally become employees of Cerence. We currently employ approximately 750 research and development personnel around the world, including scientists, engineers and technicians. Our total research and development expenses were approximately $81.0 million, $56.8 million and $53.6 million for fiscal 2018, 2017 and 2016, respectively.
We believe that continued investment in research and development will be critical for us to continue to deliver market-leading solutions for automotive cognitive assistance. Accordingly, we intend to continue to invest in our product portfolio and allocate capital and resources to our growth opportunities.
Additionally, we have taken possession of approximately 1,250 patents and patent applications previously held by Nuance. We have also entered into the Intellectual Property Agreement, which provides us with certainnon-exclusive rights with respect to patents that continue to be held by Nuance. While no individual patent or group of patents, taken alone, is considered material to our business, in the aggregate, these patents and rights provide meaningful protection for our products, technologies, and technical innovations.
Customers
Our customers include all major OEMs or their tier 1 suppliers worldwide. Our automobile manufacturer customers, commonly referred to as OEMs, include BMW, FCA Group, Ford, Daimler, Geely, Renault-Nissan, SAIC, Toyota, Volkswagen Group and many others and represented 36% of our sales in fiscal 2018. Our largest customer, Toyota, represented 19% of our revenue in fiscal 2018. Our tier 1 supplier customers, who typically sell automobile components to the OEMs, include Aptiv, Bosch, Continental, DENSO TEN, Harman and many others and represented 60% of our business in 2018.
Our revenue base is geographically diverse. In fiscal 2018, approximately 40%, 30% and 30% of our revenue came from the Americas, Europe and Asia, respectively.
Sales and Marketing and Professional Services
We market our offerings using a high-touch OEM solutions model. We sell directly to our customers, which include OEMs and suppliers and are described in “—Customers”, and for each of our customers we assign a team comprising sales and marketing as well as professional services personnel. Our customer contracts are bespoke and vary widely, but generally represent multi-year agreements providing strong visibility into future revenue and supporting retention of customer relationships over the long term.
Our sales and marketing team includes approximately 100 employees. This team includes sales representatives, account managers, sales engineers, product managers and marketing experts. As we sell our offerings to all major OEMs or their tier 1 suppliers today, our sales strategy is primarily focused on leveraging our existing client relationships. Account managers typically have longstanding relationships with specific customers and are distributed worldwide to provide local customer coverage. We oftentimes utilize customer-specific demo days in which we showcase our technology and capabilities to OEMs and tier 1 suppliers on an individual basis. These events help maintain our market presence and awareness of our platform’s offerings while also providing opportunities to solicit feedback and input from our customers on our roadmap and future technologies.
Our professional services organization includes approximately 600 employees. These employees work with our customers in the design phase of the vehicle lifecycle to tailor our platform for specific requirements such as branding and also tune the software for the characteristics of a vehicle model. Our professional services team also provides post-design phase services through maintenance engagements, particular with respect to our cloud-connected solutions. The tight integration of our platform into our customers’ design process and their vehicles
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