Organization and Basis of Presentation

12 Months Ended

Dec. 31, 2017

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Basis of Presentation

1.       Organization and Basis of Presentation

Ultragenyx Pharmaceutical Inc. (the Company) is a biopharmaceutical company and was incorporated in California on April 22, 2010. The Company subsequently reincorporated in the state of Delaware in June 2011.

The Company is focused on the identification, acquisition, development, and commercialization of novel products for the treatment of rare and ultra-rare diseases, with a focus on serious, debilitating genetic diseases. On November 15, 2017, the U.S. Food and Drug Administration (FDA), approved the Company’s first product, Mepsevii (vestronidase alfa), the first medicine approved for the treatment of children and adults with MPS VII, also known as Sly syndrome. Mepsevii is an intravenous enzyme replacement therapy for the treatment of MPS VII, a rare lysosomal storage disease that often leads to multi-organ dysfunction, pervasive skeletal disease, and death.

The Company is conducting Phase 2 and Phase 3 studies of burosumab (KRN23 or UX023), an antibody targeting fibroblast growth factor 23 (FGF23), in pediatric and adult patients with X-linked hypophosphatemia (XLH) and a Phase 2 study in tumor induced osteomalacia (TIO), both rare diseases that impair bone mineralization; a Phase 3 study for UX007 in patients with glucose transporter type-1 deficiency syndrome (Glut1 DS), a brain energy deficiency, who are experiencing movement disorders; a Phase 2 clinical study of UX007 in patients severely affected by long-chain fatty acid oxidation disorders (LC-FAOD), a genetic disorder in which the body is unable to convert long chain fatty acids into energy and a Phase 1/2 open label clinical study of DTX 301, an adeno-associated virus (AAV8) gene therapy product candidate designed for the treatment of patients with ornithine transcarbamylase (OTC) deficiency, the most common urea cycle disorder. The Company operates as one reportable segment.

In the course of its research activities, the Company has sustained operating losses and expects such annual losses to continue over the next several years. The Company’s ultimate success depends on the outcome of its research and development activities. Management expects to incur additional losses in the future to conduct product research and development and recognizes the need to raise additional capital to fully implement its business plan. Through December 31, 2017, the Company has relied primarily on the proceeds from equity offerings to finance its operations.

The Company intends to raise additional capital through the issuance of equity, borrowings, or strategic alliances with partner companies. However, if such financing is not available at adequate levels, the Company will need to reevaluate its operating plans.