Nature of Business and Basis of Presentation	6 Months Ended
Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	Nature of Business and Basis of Presentation Nature of business Mirna Therapeutics, Inc. (“Mirna” or “the Company”) is a biopharmaceutical company that has historically focused on microRNA-based oncology therapeutics. The Company was incorporated in Delaware in December 2007 as a wholly‑owned subsidiary of Asuragen, Inc. (“Asuragen”) and was spun out to existing Asuragen stockholders in December 2009. The Company is located in Austin, Texas. Following the close of the Company's Phase 1 clinical trial of MRX34 in September 2016, the Company began to evaluate its strategic alternatives focusing on enhancing stockholder value, including the possibility of a merger or sale of the Company. Mirna has discontinued further research and development activities (see Note 10) to reduce operating expenses while it evaluates these opportunities. In May 2017, the Company and Synlogic Inc., a Delaware corporation (“Synlogic”), entered into an Agreement and Plan of Merger and Reorganization (the “Merger Agreement”), pursuant to which, among other matters, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, a wholly-owned subsidiary of Mirna will merge with and into Synlogic, with Synlogic surviving as a wholly-owned subsidiary of Mirna (the “Merger”), subject to the terms of the Merger Agreement and stockholder approval of the transaction. See Note 3 below for more information regarding the Merger. The Company continues to be subject to a number of risks common to companies in similar stages of development. Principal among these risks are uncertainties of technological innovations, dependence on key individuals, development of the same or similar technological innovations by the Company’s competitors and protection of proprietary technology. The Company believes that its cash, cash equivalents and marketable securities of $47.7 million at June 30, 2017 will enable the Company to maintain its current and planned operations for at least the next 12 months. Basis of presentation The accompanying interim condensed financial statements as of June 30, 2017 and for three and six months ended June 30, 2017 and 2016, and the related interim information contained within the notes to the financial statements, are unaudited. The unaudited interim condensed financial statements of Mirna have been prepared in accordance with generally accepted accounting principles for interim financial information on a stand-alone basis without giving effect to the Merger and on the same basis as the audited financial statements. In the opinion of management, the accompanying unaudited interim condensed financial statements contain all adjustments which include only normal recurring adjustments necessary to state fairly the Company’s financial position as of June 30, 2017, and the results of its operations and cash flows for the interim periods ended June 30, 2017 and 2016. Such adjustments are of a normal and recurring nature. The interim financial data as of June 30, 2017 is not necessarily indicative of the results to be expected for the year ending December 31, 2017, or for any future period. The accompanying condensed financial statements and related financial information should be read in conjunction with the audited financial statements and related notes thereto for the year ended December 31, 2016 included in the Company’s Form 10-K, filed with the U.S. Securities and Exchange Commission (the "SEC") on March 15, 2017.

Nature of Business and Basis of Presentation

Nature of business

Mirna Therapeutics, Inc. (“Mirna” or “the Company”) is a biopharmaceutical company that has historically focused on microRNA-based oncology therapeutics. The Company was incorporated in Delaware in December 2007 as a wholly‑owned subsidiary of Asuragen, Inc. (“Asuragen”) and was spun out to existing Asuragen stockholders in December 2009. The Company is located in Austin, Texas.

Following the close of the Company's Phase 1 clinical trial of MRX34 in September 2016, the Company began to evaluate its strategic alternatives focusing on enhancing stockholder value, including the possibility of a merger or sale of the Company. Mirna has discontinued further research and development activities (see Note 10) to reduce operating expenses while it evaluates these opportunities. In May 2017, the Company and Synlogic Inc., a Delaware corporation (“Synlogic”), entered into an Agreement and Plan of Merger and Reorganization (the “Merger Agreement”), pursuant to which, among other matters, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, a wholly-owned subsidiary of Mirna will merge with and into Synlogic, with Synlogic surviving as a wholly-owned subsidiary of Mirna (the “Merger”), subject to the terms of the Merger Agreement and stockholder approval of the transaction. See Note 3 below for more information regarding the Merger.

The Company continues to be subject to a number of risks common to companies in similar stages of development. Principal among these risks are uncertainties of technological innovations, dependence on key individuals, development of the same or similar technological innovations by the Company’s competitors and protection of proprietary technology. The Company believes that its cash, cash equivalents and marketable securities of $47.7 million at June 30, 2017 will enable the Company to maintain its current and planned operations for at least the next 12 months.

Basis of presentation

The accompanying interim condensed financial statements as of June 30, 2017 and for three and six months ended June 30, 2017 and 2016, and the related interim information contained within the notes to the financial statements, are unaudited. The unaudited interim condensed financial statements of Mirna have been prepared in accordance with generally accepted accounting principles for interim financial information on a stand-alone basis without giving effect to the Merger and on the same basis as the audited financial statements. In the opinion of management, the accompanying unaudited interim condensed financial statements contain all adjustments which include only normal recurring adjustments necessary to state fairly the Company’s financial position as of June 30, 2017, and the results of its operations and cash flows for the interim periods ended June 30, 2017 and 2016. Such adjustments are of a normal and recurring nature. The interim financial data as of June 30, 2017 is not necessarily indicative of the results to be expected for the year ending December 31, 2017, or for any future period.

The accompanying condensed financial statements and related financial information should be read in conjunction with the audited financial statements and related notes thereto for the year ended December 31, 2016 included in the Company’s Form 10-K, filed with the U.S. Securities and Exchange Commission (the "SEC") on March 15, 2017.