Description of the business	3 Months Ended
Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Description of the business	1. Description of the business bluebird bio, Inc. (the “Company” or “bluebird”) was incorporated in Delaware on April 16, 1992, and is headquartered in Cambridge, Massachusetts. The Company researches, develops, manufactures and plans to commercialize gene therapies for the treatment of severe genetic diseases and cancer. Since its inception, the Company has devoted substantially all of its resources to its research and development efforts relating to its product candidates, including activities to manufacture product candidates, conduct clinical studies of its product candidates, perform preclinical research to identify new product candidates and provide general and administrative support for these operations. The Company’s programs in severe genetic diseases include ZYNTEGLO^TM (autologous CD34+ cells encoding β^A-T87Q-globin gene) as a treatment for transfusion-dependent β-thalassemia, or TDT; its LentiGlobin^® product candidate as a treatment for sickle cell disease, or SCD; and its Lenti-D^TM product candidate as a treatment for cerebral adrenoleukodystrophy, or CALD. In the second half of 2018, the Company filed a marketing authorization application with the European Medicines Agency, or EMA, for ZYNTEGLO (formerly referred to as LentiGlobin for TDT) for the treatment of patients 12 years and older with TDT who do not have a β⁰/β⁰ genotype, for whom hematopoietic stem cell (HSC) transplantation is appropriate but a human leukocyte-matched related HSC donor is not available. In March 2019, the Committee for Medicinal Products for Human Use of the EMA adopted a positive opinion recommending conditional marketing authorization for ZYNTEGLO in Europe. Assuming that the application is conditionally approved, the Company expects to begin commercializing and generating product revenues in the second half of 2019. The Company’s programs in oncology are focused on developing novel T cell-based immunotherapies, including chimeric antigen receptor (CAR) and T cell receptor (TCR) T cell therapies. Idecabtagene vicleucel, or ide-cel (bb2121), and bb21217, which are product candidates in oncology under the Company’s collaboration arrangement with Celgene Corporation (“Celgene”), are CAR T cell product candidates for the treatment of multiple myeloma. Please refer to Note 9, “Collaborative arrangements” for further discussion of the Company’s collaboration with Celgene. As of March 31, 2019, the Company had cash, cash equivalents and marketable securities of $1.73 billion. Although the Company has incurred recurring losses and expects to continue to incur losses for the foreseeable future, the Company expects that its existing cash, cash equivalents and marketable securities will be sufficient to fund current planned operations for at least the next twelve months.

Description of the business

3 Months Ended

Mar. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

1. Description of the business

bluebird bio, Inc. (the “Company” or “bluebird”) was incorporated in Delaware on April 16, 1992, and is headquartered in Cambridge, Massachusetts. The Company researches, develops, manufactures and plans to commercialize gene therapies for the treatment of severe genetic diseases and cancer. Since its inception, the Company has devoted substantially all of its resources to its research and development efforts relating to its product candidates, including activities to manufacture product candidates, conduct clinical studies of its product candidates, perform preclinical research to identify new product candidates and provide general and administrative support for these operations.

The Company’s programs in severe genetic diseases include ZYNTEGLO^TM (autologous CD34+ cells encoding β^A-T87Q-globin gene) as a treatment for transfusion-dependent β-thalassemia, or TDT; its LentiGlobin^® product candidate as a treatment for sickle cell disease, or SCD; and its Lenti-D^TM product candidate as a treatment for cerebral adrenoleukodystrophy, or CALD. In the second half of 2018, the Company filed a marketing authorization application with the European Medicines Agency, or EMA, for ZYNTEGLO (formerly referred to as LentiGlobin for TDT) for the treatment of patients 12 years and older with TDT who do not have a β⁰/β⁰ genotype, for whom hematopoietic stem cell (HSC) transplantation is appropriate but a human leukocyte-matched related HSC donor is not available. In March 2019, the Committee for Medicinal Products for Human Use of the EMA adopted a positive opinion recommending conditional marketing authorization for ZYNTEGLO in Europe. Assuming that the application is conditionally approved, the Company expects to begin commercializing and generating product revenues in the second half of 2019. The Company’s programs in oncology are focused on developing novel T cell-based immunotherapies, including chimeric antigen receptor (CAR) and T cell receptor (TCR) T cell therapies. Idecabtagene vicleucel, or ide-cel (bb2121), and bb21217, which are product candidates in oncology under the Company’s collaboration arrangement with Celgene Corporation (“Celgene”), are CAR T cell product candidates for the treatment of multiple myeloma. Please refer to Note 9, “Collaborative arrangements” for further discussion of the Company’s collaboration with Celgene.

As of March 31, 2019, the Company had cash, cash equivalents and marketable securities of $1.73 billion. Although the Company has incurred recurring losses and expects to continue to incur losses for the foreseeable future, the Company expects that its existing cash, cash equivalents and marketable securities will be sufficient to fund current planned operations for at least the next twelve months.