Dr. Tidmarsh received M.D. and Ph.D. from Stanford University, where he also completed fellowship training in Pediatric Oncology and Neonatology and is currently Adjunct Faculty of Pediatrics and Neonatology. He served as clinical faculty at Stanford for a number of years after fellowship prior to devoting his full time to clinical research and development in order to bring new treatments through the FDA approval process. Dr. Tidmarsh was President, Chief Executive Officer, Secretary and a Director of La Jolla Pharmaceutical Company from January 2012 until November 2019. While at La Jolla, Dr. Tidmarsh helped discover the use of angiotensin II for the treatment of shock and led all aspects of the development including approval by the US FDA and the EMA for the treatment of patients suffering from distributive shock. He also led the development of artesunate for the treatment of severe malaria, now pending action for potential approval at the FDA. Dr. Tidmarsh has over 30 years of experience in biotechnology, including the successful clinical development of three FDA-approved drugs. He previously served as the Chief Executive Officer of Horizon Pharma, Inc., a company he founded in 2005. While at Horizon, he led all aspects of development of Duexis, which was approved by the FDA for the treatment of rheumatoid arthritis. He also founded Threshold Pharmaceuticals, Inc. and held senior positions at Coulter Pharmaceutical, Inc. (acquired by GlaxoSmithKline) and SEQUUS Pharmaceuticals, Inc. (acquired by Johnson & Johnson). While at Coulter and SEQUUS, Dr. Tidmarsh led the clinical development of BEXXAR and Doxil, respectively, two FDA-approved anti-cancer agents.

At Stanford, Dr. Tidmarsh is devoted to teaching clinical research and development to residents, fellows and junior faculty. In addition, he is working to help improve the quality of medical care through various efforts which include serving on the board of Lucile Packard Foundation for Children's Health.