Formation and Business of the Company	3 Months Ended
Mar. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Formation and Business of the Company	1. Formation and Business of the Company MyoKardia, Inc., incorporated under the laws of the State of Delaware in June 2012, is a clinical stage biopharmaceutical company pioneering a precision medicine approach to discover, develop and commercialize targeted therapies for the treatment of serious and neglected rare cardiovascular diseases. Our initial focus is on the treatment of heritable cardiomyopathies, a group of rare, genetically-driven forms of heart failure that result from biomechanical defects in cardiac muscle contraction. We have used our precision medicine platform to generate an initial pipeline of four therapeutic programs for the chronic treatment of the two most common forms of heritable cardiomyopathy—hypertrophic cardiomyopathy (“HCM”), and dilated cardiomyopathy (“DCM”). We have discovered and advanced our lead product candidate, MYK-461, into Phase 1 clinical development. In our first Phase 1 clinical trial, we have demonstrated proof of mechanism, or the ability of MYK-461 to reduce cardiac muscle contraction, an important biomarker of disease. We intend to expand our approach to deliver treatments with disease-modifying potential for patients with other forms of genetically-driven heart failure. The accompanying unaudited Condensed Consolidated Financial Statements have been prepared on a going-concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Through March 31, 2016, the Company has financed its operations through an initial public offering (“IPO”) and private placements of redeemable convertible preferred stock and funds received in connection with a license and collaboration agreement with Aventis Inc., a wholly-owned subsidiary of Sanofi S.A., entered into in August 2014 (the “Collaboration Agreement”) (See Note 4). The Company received net proceeds of $93.9 million from the sale of shares of its Series A, A-1 and B redeemable convertible preferred stock. On November 3, 2015, the Company completed its IPO of 6,253,125 shares of common stock at an offering price of $10.00 per share, resulting in net proceeds of approximately $55.6 million, after deducting underwriting discounts, commissions and offering costs. The Company has incurred significant losses and negative cash flows from operations. As at March 31, 2016, the Company had an accumulated deficit of $73.1 million and cash and cash equivalents of $99.5 million, which it believes will be sufficient to fund its planned operations through at least the next twelve months. The accompanying unaudited Condensed Consolidated Financial Statements, in the opinion of management, include all adjustments which the Company considers necessary for the fair statement of the Condensed Consolidated Results of Operations and Comprehensive Loss and Cash Flows for the interim periods covered and the Condensed Consolidated Financial Position of the Company at the date of the balance sheets. The consolidated financial statements of the Company as at December 31, 2015 included the Company’s accounts and have been prepared in conformity with accounting principles generally accepted in the United States of America (“US GAAP”). The interim results presented herein are not necessarily indicative of the results of operations that may be expected for the full fiscal year ending December 31, 2016, or any other future period. The accompanying unaudited Condensed Consolidated Financial Statements and related financial information should be read in conjunction with the Company’s audited consolidated financial statements and the related notes thereto for the year ended December 31, 2015 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 filed with the U.S. Securities and Exchange Commission (the “SEC”) on March 18, 2016 (the “Annual Report”).

1. Formation and Business of the Company

MyoKardia, Inc., incorporated under the laws of the State of Delaware in June 2012, is a clinical stage biopharmaceutical company pioneering a precision medicine approach to discover, develop and commercialize targeted therapies for the treatment of serious and neglected rare cardiovascular diseases. Our initial focus is on the treatment of heritable cardiomyopathies, a group of rare, genetically-driven forms of heart failure that result from biomechanical defects in cardiac muscle contraction. We have used our precision medicine platform to generate an initial pipeline of four therapeutic programs for the chronic treatment of the two most common forms of heritable cardiomyopathy—hypertrophic cardiomyopathy (“HCM”), and dilated cardiomyopathy (“DCM”). We have discovered and advanced our lead product candidate, MYK-461, into Phase 1 clinical development. In our first Phase 1 clinical trial, we have demonstrated proof of mechanism, or the ability of MYK-461 to reduce cardiac muscle contraction, an important biomarker of disease. We intend to expand our approach to deliver treatments with disease-modifying potential for patients with other forms of genetically-driven heart failure.

The accompanying unaudited Condensed Consolidated Financial Statements have been prepared on a going-concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. Through March 31, 2016, the Company has financed its operations through an initial public offering (“IPO”) and private placements of redeemable convertible preferred stock and funds received in connection with a license and collaboration agreement with Aventis Inc., a wholly-owned subsidiary of Sanofi S.A., entered into in August 2014 (the “Collaboration Agreement”) (See Note 4). The Company received net proceeds of $93.9 million from the sale of shares of its Series A, A-1 and B redeemable convertible preferred stock. On November 3, 2015, the Company completed its IPO of 6,253,125 shares of common stock at an offering price of $10.00 per share, resulting in net proceeds of approximately $55.6 million, after deducting underwriting discounts, commissions and offering costs. The Company has incurred significant losses and negative cash flows from operations. As at March 31, 2016, the Company had an accumulated deficit of $73.1 million and cash and cash equivalents of $99.5 million, which it believes will be sufficient to fund its planned operations through at least the next twelve months.

The accompanying unaudited Condensed Consolidated Financial Statements, in the opinion of management, include all adjustments which the Company considers necessary for the fair statement of the Condensed Consolidated Results of Operations and Comprehensive Loss and Cash Flows for the interim periods covered and the Condensed Consolidated Financial Position of the Company at the date of the balance sheets. The consolidated financial statements of the Company as at December 31, 2015 included the Company’s accounts and have been prepared in conformity with accounting principles generally accepted in the United States of America (“US GAAP”). The interim results presented herein are not necessarily indicative of the results of operations that may be expected for the full fiscal year ending December 31, 2016, or any other future period.

The accompanying unaudited Condensed Consolidated Financial Statements and related financial information should be read in conjunction with the Company’s audited consolidated financial statements and the related notes thereto for the year ended December 31, 2015 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 filed with the U.S. Securities and Exchange Commission (the “SEC”) on March 18, 2016 (the “Annual Report”).