Kim D. Blickenstaff has served as our President and Chief Executive Officer and as one of our directors since September 2007. Prior to joining our company, Mr. Blickenstaff served as Chairman and Chief Executive Officer of Biosite Incorporated, a provider of medical diagnostic products, from 1988 until its acquisition by Inverness Medical Innovations, Inc. in June 2007. Mr. Blickenstaff currently serves as Chairman of Medivation, Inc. (NASDAQ: MDVN), and is a member of its audit committee and compensation committee. He previously served as a director of DexCom, Inc. (NASDAQ: DXCM), a provider of glucose monitoring systems, from June 2001 to September 2007. Mr. Blickenstaff was formerly a certified public accountant and has more than 20 years of experience overseeing the preparation of financial statements. He received a B.A. in Political Science from Loyola University, Chicago, and an M.B.A. from the Graduate School of Business, Loyola University, Chicago.
David Berger joined Tandem in August 2013. Prior to joining the company, he served as Senior Vice President, General Counsel and Corporate Secretary at Senomyx, Inc., which he joined in 2008. His prior experience includes serving as Vice President, Legal Affairs at Biosite Incorporated, where he was the managing attorney responsible for all commercial aspects of legal affairs, and serving as an attorney with Cooley Godward LLP. Mr. Berger received his J.D. at Stanford Law School and a B.A. in Economics from the University of California, Berkeley.
John Cajigas has served as our Chief Financial Officer since May 2008. Prior to joining our company, Mr. Cajigas served in various accounting and finance positions, most recently as Vice President, Finance, of Biosite from August 1995 until August 2007. Prior to joining Biosite, Mr. Cajigas worked as an Audit Manager with Ernst & Young LLP, working primarily with clients in the technology and biotechnology industries. Mr. Cajigas is a certified public accountant (inactive) and holds a B.S. in Business Administration (Accounting) from San Diego State University.
Brian Hansen joined us as our Executive Vice President and Chief Commercial Officer in February 2016 with more than 20 years of sales and leadership experience in the clinical diagnostics industry. Prior to joining Tandem, Mr. Hansen was Chief Commercial Officer at Adaptive Biotechnologies Corporation. Before that, he held executive and senior-level positions at Genoptix (a Novartis-owned company), Gen-Probe (acquired by Hologic in 2012) and Fisher Scientific. Mr. Hansen received an MBA from the School of Business at San Diego State University and a B.S. in Business Administration from the University of Missouri-Columbia.
Keith Kogler was appointed Vice President, Engineering in September 2016. He previously served as Senior Director of our Program Management Office. Mr. Kogler has over 25 years of experience directing cross-functional medical device development and commercialization teams. Prior to joining Tandem, Mr. Kogler was Director, Drug Delivery PMO at Amgen. Before that, he held various senior-level positions including Director, Research and Development for Trifoil Imaging (Formerly Gamma Medica, Inc.), Senior Vice President, Research and Development for InfiMed/Varian Medical Systems, and Director, Product Commercialization for Carestream Health. Mr. Kogler received a Bachelor's of Science in Software Engineering from Rochester Institute of Technology. In addition, he holds eight patents in medical systems and devices.
Jim Leal joined Tandem in October 2010 as the Vice President of Operations, bringing 25 years of manufacturing and engineering experience. Previously, Jim was the Vice President of Manufacturing and Field Support for Volcano Corporation and held Director Roles with CardioNet, Inc. and Digirad Corporation. He held Senior Engineering roles with FlipChip Technologies and Hughes Aircraft Company. Jim has won several awards including a Hughes Aircraft Doctoral and Masters Fellowship and was a recognized nominee for Most Promising Hispanic Engineer of the Year Award. Mr. Leal is a published author and patent holder. He is a University of Arizona graduate with a Ph.D. in Materials Science and Engineering.
Susan Morrison was appointed Chief Administrative Officer in September 2013. She previously served as our Vice President, Human Resources, Corporate and Investor Relations since April 2013. Ms. Morrison served as our Director, Corporate and Investor Relations, from January 2009 to March 2013, and was our Director, Corporate Services from November 2007 to December 2008. Prior to joining our company, Ms. Morrison held various positions in Corporate and Investor Relations at Biosite from August 2003 through November 2007. Ms. Morrison holds a B.A. in Public Relations from Western Michigan University.
John Sheridan has served as our Executive Vice President and Chief Operating Officer since April 2013. Prior to joining our company, Mr. Sheridan served as Chief Operating Officer of Rapiscan Systems, Inc., a provider of security equipment and systems, from March 2012 to February 2013. Mr. Sheridan served as Executive Vice President of Research and Development and Operations for Volcano Corporation (NASDAQ: VOLC), a medical technology company, from November 2004 to March 2010. From May 2002 to May 2004, Mr. Sheridan served as Executive Vice President of Operations at CardioNet, Inc., a medical technology company. From March 1998 to May 2002, he served as Vice President of Operations at Digirad Corporation, a medical imaging company. Mr. Sheridan holds a B.S. in Chemistry from the University of West Florida and an M.B.A. from Boston University.
Leigh Vosseller has served as our VP of Finance since September 2013. Prior to joining Tandem, Leigh served in various senior finance positions in the healthcare industry. Most recently, she was Vice President and CFO of Genoptix, Inc. (a Novartis company). Prior to that she held a senior finance position at Biosite Incorporated where she played a key role in developing the financial and administrative infrastructure for international expansion. Ms. Vosseller is a certified public accountant (inactive) and holds a bachelor’s degree in accounting from Missouri State University.