The Company and Basis of Presentation	6 Months Ended
The Company and Basis of Presentation	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company and Basis of Presentation	The Company and Basis of Presentation Insmed is a global biopharmaceutical company on a mission to transform the lives of patients with serious and rare diseases. The Company's first commercial product, ARIKAYCE (amikacin liposome inhalation suspension), received accelerated approval in the United States (US) in September 2018 for the treatment of Mycobacterium avium complex (MAC) lung disease as part of a combination antibacterial drug regimen for adult patients with limited or no alternative treatment options in a refractory setting. Nontuberculous mycobacterial (NTM) lung disease caused by MAC (which the Company refers to as MAC lung disease) is a rare and often chronic infection that can cause irreversible lung damage and can be fatal. The Company's clinical-stage pipeline includes brensocatib (formerly known as INS1007) and treprostinil palmitil (formerly known as INS1009). Brensocatib is a novel oral, reversible inhibitor of dipeptidyl peptidase 1 with therapeutic potential in bronchiectasis and other inflammatory diseases. Treprostinil palmitil is an inhaled formulation of a treprostinil prodrug that may offer a differentiated product profile for rare pulmonary disorders, including pulmonary arterial hypertension. The Company was incorporated in the Commonwealth of Virginia on November 29, 1999 and its principal executive offices are in Bridgewater, New Jersey. The Company has legal entities in the US, France, Germany, Ireland, Italy, the Netherlands, the United Kingdom (UK), Switzerland, Japan and Bermuda. The accompanying unaudited interim consolidated financial statements have been prepared pursuant to the rules and regulations for reporting on Form 10-Q. Accordingly, certain information and disclosures required by accounting principles generally accepted in the US for complete consolidated financial statements are not included herein. The unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019. The results of operations of any interim period are not necessarily indicative of the results of operations for the full year. The unaudited interim consolidated financial information presented herein reflects all normal adjustments that are, in the opinion of management, necessary for a fair statement of the financial position, results of operations and cash flows for the periods presented. All intercompany transactions and balances have been eliminated in consolidation and certain prior year amounts have been reclassified to conform to the current year presentation. The Company had $641.9 million in cash and cash equivalents as of June 30, 2020 and reported a net loss of $128.2 million for the six months ended June 30, 2020. In the second quarter of 2020, the Company completed an underwritten offering of 11,155,000 shares of the Company's common stock, including 1,455,000 shares issued pursuant to the exercise in full of the underwriters' option to purchase additional shares from the Company, at a public offering price of $23.25 per share. The Company's net proceeds from the sale of the shares, after deducting the underwriting discounts and offering expenses of $13.4 million, were $245.9 million. Historically, the Company has funded its operations through public offerings of equity securities and debt financings. The Company commenced commercial shipments of ARIKAYCE in October 2018. The Company expects to continue to incur operating losses both at its US and certain international entities while funding research and development (R&D) activities for ARIKAYCE, brensocatib and its other pipeline programs, continuing commercialization activities for ARIKAYCE in the US, continuing to invest in pre-commercial and regulatory activities for ARIKAYCE in Europe and Japan, and funding other general and administrative activities. The Company expects its future cash requirements to be substantial, and the Company may need to raise additional capital to fund operations, including the continued commercialization of ARIKAYCE and additional clinical trials related to ARIKAYCE, to develop brensocatib and treprostinil palmitil and to develop, acquire, in-license or co-promote other products or product candidates, including those that address orphan or rare diseases. The source, timing and availability of any future financing or other transaction will depend principally upon continued progress in the Company’s commercial, regulatory and development activities. Any equity or debt financing will also be contingent upon equity and debt market conditions and interest rates at the time. If the Company is unable to obtain sufficient additional funds when required, the Company may be forced to delay, restrict or eliminate all or a portion of its development programs or commercialization efforts. The Company believes it currently has sufficient funds to meet its financial needs for at least the next 12 months. Risks and Uncertainties - There are many uncertainties regarding the novel coronavirus (COVID-19) pandemic, and the Company is closely monitoring the impact of the pandemic on all aspects of its business, including how the pandemic will impact its patients, employees, suppliers, vendors, business partners and distribution channels. While the pandemic did not materially affect the Company's financial results and business operations for the six months ended June 30, 2020, the Company is unable to predict the impact that COVID-19 will have on its financial position and operating results in future periods due to numerous uncertainties. The Company will continue to assess the evolving impact of the COVID-19 pandemic and will make adjustments to its operations as necessary.