1. Nature of the Business and Basis of Presentation Rubius Therapeutics, Inc. (Rubius or the Company) is a therapeutics company focused on using its platform to develop red cell therapeutics for the treatment of patients with severe diseases. Rubius was incorporated in April 2013 as VL26, Inc. under the laws of the State of Delaware. In January 2015, the Company changed its name to Rubius Therapeutics, 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, the ability to establish clinical- and commercial-scale manufacturing processes and the ability to secure additional capital to fund operations. In addition, the Company is subject to uncertainty regarding the performance and safety of red cell therapeutics in humans. 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 Companys drug development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. On July 20, 2018, the Company completed its initial public offering (IPO), pursuant to which it issued and sold 12,055,450 shares of common stock, inclusive of 1,572,450 shares sold by the Company pursuant to the full exercise of the underwriters option to purchase additional shares. The aggregate net proceeds received by the Company from the IPO were $254.3 million, after deducting underwriting discounts and commissions and other offering costs. Upon the closing of the IPO, all of the shares of the Companys outstanding convertible preferred stock then outstanding automatically converted into 51,845,438 shares of common stock (see Note 7). The accompanying condensed consolidated 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. The Company has incurred recurring losses since inception, including net losses of $32.6 million for the three months ended March 31, 2019 and $89.2 million for the year ended December 31, 2018. As of March 31, 2019, the Company had an accumulated deficit of $181.9 million. The Company expects to continue to generate operating losses in the foreseeable future. As of May 15, 2019, the issuance date of the interim condensed consolidated financial statements, the Company expects that its cash, cash equivalents and investments will be sufficient to fund its operating expenses and capital expenditure requirements for at least 12 months from the issuance date of the interim condensed consolidated financial statements. The Company may seek additional funding through private or public equity financings, debt financings, collaborations, strategic alliances and marketing, distribution or licensing arrangements. The Company may not be able to obtain financing on acceptable terms, or at all, and the Company may not be able to enter into collaborations or other arrangements. The terms of any financing may adversely affect the holdings or the rights of the Company's stockholders. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its research and development programs, product portfolio expansion or commercialization efforts, which could adversely affect its business prospects. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all. The Companys condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). The accompanying condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany accounts and transactions have been eliminated in consolidation. Certain prior period amounts have been reclassified to conform to the current year presentation.