Nature of the Business and Basis of Presentation	9 Months Ended
Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of the Business and Basis of Presentation	1. Nature of the Business and Basis of Presentation Constellation Pharmaceuticals, Inc. (“Constellation” or the “Company”) is a clinical-stage biopharmaceutical company using its expertise in epigenetics to discover and develop novel therapeutics that address serious unmet medical needs in patients with cancers associated with abnormal gene expression or drug resistance. The Company was incorporated in January 2008 as EpiGenetiX, Inc. under the laws of the State of Delaware. On March 31, 2008, the Company changed its name to Constellation Pharmaceuticals, Inc. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s drug development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The accompanying financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has funded its operations with the sales of convertible preferred stock, payments received in connection with collaboration agreements, borrowings under loan agreements, and proceeds from the initial public offering (“IPO”) completed in July 2018. On March 20, 2019, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Hercules Capital, Inc. (“Hercules”) pursuant to which Hercules agreed to provide the Company with up to $40.0 million in funding, to be made available in four tranches. As of September 30, 2019, the Company had drawn down on the first and second of the four tranches and in connection with the draw down received net proceeds of $29.5 million. In addition, on October 3, 2019, the Company completed a private placement of an aggregate of 7,647,057 shares of its common stock and received net proceeds of approximately $64.9 million. The Company has incurred losses since inception, including net losses of $21.1 million and $61.3 million for the three and nine months ended September 30, 2019, respectively, and $59.9 million for the year ended December 31, 2018. As of September 30, 2019, the Company had an accumulated deficit of $295.2 million. The Company expects to continue to generate operating losses in the foreseeable future. Based on the Company’s current operating plan, the Company expects that its cash, cash equivalents and marketable securities at September 30, 2019, together with the net proceeds from the private placement (see Note 16), will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance date of the interim financial statements. Management’s belief with respect to its ability to fund operations is based on estimates that are subject to risks and uncertainties. If actual results are different from management’s estimates, the Company may need to seek additional funding sooner than would otherwise be expected. There can be no assurance that the Company will be able to obtain additional funding on acceptable terms, if at all. The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”).

Nature of the Business and Basis of Presentation

9 Months Ended

Sep. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Nature of the Business and Basis of Presentation

1. Nature of the Business and Basis of Presentation

Constellation Pharmaceuticals, Inc. (“Constellation” or the “Company”) is a clinical-stage biopharmaceutical company using its expertise in epigenetics to discover and develop novel therapeutics that address serious unmet medical needs in patients with cancers associated with abnormal gene expression or drug resistance. The Company was incorporated in January 2008 as EpiGenetiX, Inc. under the laws of the State of Delaware. On March 31, 2008, the Company changed its name to Constellation Pharmaceuticals, Inc.

The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s drug development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

The accompanying financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has funded its operations with the sales of convertible preferred stock, payments received in connection with collaboration agreements, borrowings under loan agreements, and proceeds from the initial public offering (“IPO”) completed in July 2018. On March 20, 2019, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Hercules Capital, Inc. (“Hercules”) pursuant to which Hercules agreed to provide the Company with up to $40.0 million in funding, to be made available in four tranches. As of September 30, 2019, the Company had drawn down on the first and second of the four tranches and in connection with the draw down received net proceeds of $29.5 million. In addition, on October 3, 2019, the Company completed a private placement of an aggregate of 7,647,057 shares of its common stock and received net proceeds of approximately $64.9 million.

The Company has incurred losses since inception, including net losses of $21.1 million and $61.3 million for the three and nine months ended September 30, 2019, respectively, and $59.9 million for the year ended December 31, 2018. As of September 30, 2019, the Company had an accumulated deficit of $295.2 million. The Company expects to continue to generate operating losses in the foreseeable future. Based on the Company’s current operating plan, the Company expects that its cash, cash equivalents and marketable securities at September 30, 2019, together with the net proceeds from the private placement (see Note 16), will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance date of the interim financial statements. Management’s belief with respect to its ability to fund operations is based on estimates that are subject to risks and uncertainties. If actual results are different from management’s estimates, the Company may need to seek additional funding sooner than would otherwise be expected. There can be no assurance that the Company will be able to obtain additional funding on acceptable terms, if at all.

The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”).