Organization and Business	6 Months Ended
Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Business	1. Organization and Business Synthorx, Inc. (the “Company”) was incorporated in the state of Delaware in January 2014 and is based in San Diego, California. The Company is a clinical-stage biopharmaceutical company focused on prolonging and improving the lives of people with cancer and autoimmune disorders. The Company’s platform technology expands the genetic code by adding a new DNA base pair and is designed to create optimized biologics, which the Company refers to as Synthorins. The Company has incurred significant operating losses since inception and expects to incur operating losses for the foreseeable future as it pursues the clinical and preclinical development of its programs and product candidates. As the Company continues to incur losses, its transition to profitability will depend on the successful development, approval and commercialization of its product candidates and on the achievement of sufficient revenues to support its cost structure. The Company may never achieve profitability, and unless and until it does, will need to continue to raise additional capital to fund its operations.

Organization and Business

6 Months Ended

Jun. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

1. Organization and Business

Synthorx, Inc. (the “Company”) was incorporated in the state of Delaware in January 2014 and is based in San Diego, California. The Company is a clinical-stage biopharmaceutical company focused on prolonging and improving the lives of people with cancer and autoimmune disorders. The Company’s platform technology expands the genetic code by adding a new DNA base pair and is designed to create optimized biologics, which the Company refers to as Synthorins.

The Company has incurred significant operating losses since inception and expects to incur operating losses for the foreseeable future as it pursues the clinical and preclinical development of its programs and product candidates. As the Company continues to incur losses, its transition to profitability will depend on the successful development, approval and commercialization of its product candidates and on the achievement of sufficient revenues to support its cost structure. The Company may never achieve profitability, and unless and until it does, will need to continue to raise additional capital to fund its operations.