Organization and Basis of Presentation	3 Months Ended
Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Eleven Biotherapeutics, Inc. (the “Company”), a Delaware corporation, is a biologics oncology company focused primarily on designing, engineering and developing targeted next generation antibody drug conjugates ("ADC"s). The Company's next generation ADCs are single protein therapeutics composed of targeting moieties genetically fused via linker domains to cytotoxic protein payloads that are produced through the Company's proprietary one-step manufacturing process. The Company targets tumor cell surface antigens that allow for rapid internalization into the targeted cancer cell while also having limited expression on normal cells. The Company has designed its next generation ADCs to overcome the fundamental efficacy and safety challenges inherent in existing ADCs, where a payload is chemically attached to a targeting antibody. Basis of presentation The condensed consolidated financial statements as of March 31, 2018 and December 31, 2017 and for the three months ended March 31, 2018 and 2017 and the related information contained within the notes to the condensed consolidated financial statements are unaudited. The unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting standards applicable to interim financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s consolidated financial position as of March 31, 2018 and its results of operations and its cash flows for the three months ended March 31, 2018 and 2017. The financial data and the other financial information disclosed in these notes to the condensed consolidated financial statements related to the three-month periods are also unaudited. The results of operations for the three months ended March 31, 2018 are not necessarily indicative of the results to be expected for the year ending December 31, 2018 or for any other future annual or interim period. The condensed 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, 2017 that was filed with the Securities and Exchange Commission (“SEC”) on April 2, 2018 (the "2017 Form 10-K"). The condensed consolidated financial statements include the accounts of Eleven Biotherapeutics, Inc., its wholly owned subsidiary, Viventia Bio Inc. ("Viventia"), and its indirect subsidiaries, Viventia Bio USA Inc. and Viventia Biotech (EU) Limited. All inter-company transactions and balances have been eliminated in consolidation. The condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles. The functional currency of Viventia Bio Inc., Viventia Bio USA Inc. and Viventia Biotech (EU) Limited is the U.S. dollar. Liquidity The Company has financed its operations to date primarily through debt and equity offerings and collaboration and licensing arrangements. As of March 31, 2018, the Company had cash and cash equivalents totaling $19.7 million, net working capital of $15.1 million and an accumulated deficit of $156.3 million. On March 23, 2018, the Company raised approximately $9.0 million of net proceeds from the sale of 7,968,128 shares of common stock at a price of $1.13 per share in a registered direct offering and the sale of common stock purchase warrants to purchase 7,968,128 shares of common stock at a price of $0.125 for each warrant to purchase one share of common stock in a concurrent private placement (collectively, the “March 2018 Financing”). Subject to certain ownership limitations, the common stock purchase warrants issued in the March 2018 Financing were exercisable immediately upon issuance at an exercise price equal to $1.20 per share of common stock, subject to adjustments as provided under the terms of such common stock purchase warrants. The common stock purchase warrants are exercisable for five years from March 23, 2018. In addition, between April 1, 2018 and May 10, 2018, the Company received proceeds of $4.2 million from the issuance of 5.2 million shares of common stock due to the exercise of common stock purchase warrants issued in connection with its underwritten public offering in November 2017 ("November 2017 Financing"). Management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued, and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Generally, to be considered probable of being effectively implemented, the plans must have been approved by the Company’s board of directors ("Board") before the date that the financial statements are issued. The future success of the Company is dependent on its ability to develop its product candidates and ultimately upon its ability to attain profitable operations. The Company is subject to a number of risks similar to other early-stage life science companies, including, but not limited to, successful discovery and development of its product candidates, raising additional capital with favorable terms, development by its competitors of new technological innovations, protection of proprietary technology and market acceptance of the Company’s products. The successful discovery and development of product candidates requires substantial working capital which may not be available to the Company on favorable terms or not at all. To date, the Company has no revenue from product sales and management expects continuing operating losses in the future. As of March 31, 2018, the Company had available cash and cash equivalents of $19.7 million, which it believes, together with the additional $4.2 million of proceeds received between April 1, 2018 and May 10, 2018 from the issuance of 5.2 million shares of common stock due to the exercise of common stock purchase warrants issued in the November 2017 Financing, is not sufficient to fund the Company’s current operating plan for twelve months from the date of issuance of these financial statements. Management expects to seek additional funds through equity or debt financings or through additional collaboration, licensing transactions or other sources. The Company may be unable to obtain equity or debt financings or enter into additional collaboration or licensing transactions and, if necessary, the Company will be required to implement cost reduction strategies. These factors raise substantial doubt about the Company’s ability to continue as a going concern. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The condensed consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.

Organization and Basis of Presentation

Eleven Biotherapeutics, Inc. (the “Company”), a Delaware corporation, is a biologics oncology company focused primarily on designing, engineering and developing targeted next generation antibody drug conjugates ("ADC"s). The Company's next generation ADCs are single protein therapeutics composed of targeting moieties genetically fused via linker domains to cytotoxic protein payloads that are produced through the Company's proprietary one-step manufacturing process. The Company targets tumor cell surface antigens that allow for rapid internalization into the targeted cancer cell while also having limited expression on normal cells. The Company has designed its next generation ADCs to overcome the fundamental efficacy and safety challenges inherent in existing ADCs, where a payload is chemically attached to a targeting antibody.

Basis of presentation

The condensed consolidated financial statements as of March 31, 2018 and December 31, 2017 and for the three months ended March 31, 2018 and 2017 and the related information contained within the notes to the condensed consolidated financial statements are unaudited. The unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting standards applicable to interim financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s consolidated financial position as of March 31, 2018 and its results of operations and its cash flows for the three months ended March 31, 2018 and 2017. The financial data and the other financial information disclosed in these notes to the condensed consolidated financial statements related to the three-month periods are also unaudited. The results of operations for the three months ended March 31, 2018 are not necessarily indicative of the results to be expected for the year ending December 31, 2018 or for any other future annual or interim period. The condensed 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, 2017 that was filed with the Securities and Exchange Commission (“SEC”) on April 2, 2018 (the "2017 Form 10-K").

The condensed consolidated financial statements include the accounts of Eleven Biotherapeutics, Inc., its wholly owned subsidiary, Viventia Bio Inc. ("Viventia"), and its indirect subsidiaries, Viventia Bio USA Inc. and Viventia Biotech (EU) Limited. All inter-company transactions and balances have been eliminated in consolidation. The condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles.

The functional currency of Viventia Bio Inc., Viventia Bio USA Inc. and Viventia Biotech (EU) Limited is the U.S. dollar.

Liquidity

The Company has financed its operations to date primarily through debt and equity offerings and collaboration and licensing arrangements. As of March 31, 2018, the Company had cash and cash equivalents totaling $19.7 million, net working capital of $15.1 million and an accumulated deficit of $156.3 million.

On March 23, 2018, the Company raised approximately $9.0 million of net proceeds from the sale of 7,968,128 shares of common stock at a price of $1.13 per share in a registered direct offering and the sale of common stock purchase warrants to purchase 7,968,128 shares of common stock at a price of $0.125 for each warrant to purchase one share of common stock in a concurrent private placement (collectively, the “March 2018 Financing”). Subject to certain ownership limitations, the common stock purchase warrants issued in the March 2018 Financing were exercisable immediately upon issuance at an exercise price equal to $1.20 per share of common stock, subject to adjustments as provided under the terms of such common stock purchase warrants. The common stock purchase warrants are exercisable for five years from March 23, 2018.

In addition, between April 1, 2018 and May 10, 2018, the Company received proceeds of $4.2 million from the issuance of 5.2 million shares of common stock due to the exercise of common stock purchase warrants issued in connection with its underwritten public offering in November 2017 ("November 2017 Financing").

Management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued, and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Generally, to be considered probable of being effectively implemented, the plans must have been approved by the Company’s board of directors ("Board") before the date that the financial statements are issued.

The future success of the Company is dependent on its ability to develop its product candidates and ultimately upon its ability to attain profitable operations. The Company is subject to a number of risks similar to other early-stage life science companies, including, but not limited to, successful discovery and development of its product candidates, raising additional capital with favorable terms, development by its competitors of new technological innovations, protection of proprietary technology and market acceptance of the Company’s products. The successful discovery and development of product candidates requires substantial working capital which may not be available to the Company on favorable terms or not at all.

To date, the Company has no revenue from product sales and management expects continuing operating losses in the future. As of March 31, 2018, the Company had available cash and cash equivalents of $19.7 million, which it believes, together with the additional $4.2 million of proceeds received between April 1, 2018 and May 10, 2018 from the issuance of 5.2 million shares of common stock due to the exercise of common stock purchase warrants issued in the November 2017 Financing, is not sufficient to fund the Company’s current operating plan for twelve months from the date of issuance of these financial statements. Management expects to seek additional funds through equity or debt financings or through additional collaboration, licensing transactions or other sources. The Company may be unable to obtain equity or debt financings or enter into additional collaboration or licensing transactions and, if necessary, the Company will be required to implement cost reduction strategies. These factors raise substantial doubt about the Company’s ability to continue as a going concern. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The condensed consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.