License Agreement with Roche	12 Months Ended
Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License Agreement with Roche	License Agreement with Roche On June 10, 2016, the Company entered into the License Agreement with Roche, which became effective on August 16, 2016. Under the License Agreement, the Company granted Roche an exclusive, worldwide license, including the right to sublicense, to its patent rights and know-how related to the Company’s monoclonal antibody EBI-031 or any other IL-6 antagonist anti-IL-6 monoclonal antibody, to make, have made, use, have used, register, have registered, sell, have sold, offer for sale, import and export any product containing such an antibody or any companion diagnostic used to predict or monitor response to treatment with such a product (collectively, the “Licensed Intellectual Property”). Under the License Agreement, Roche is required to continue developing EBI-031 and any other product made from the Licensed Intellectual Property that contains an IL-6 antagonist anti-IL-6 monoclonal antibody (a “Licensed Product”) at its cost. Financial Terms The Company received an upfront license fee of $7.5 million from Roche and Roche agreed to pay up to an additional $262.5 million upon the achievement of specified regulatory, development and commercial milestones with respect to up to two unrelated indications. Specifically, an aggregate amount of up to $197.5 million is payable to the Company for the achievement of specified milestones with respect to the first indication: $72.5 million in development milestones, $50.0 million in regulatory milestones and $75.0 million in commercialization milestones. Additional amounts of up to $65.0 million are payable upon the achievement of specified development and regulatory milestones in a second indication. The first development milestone payment for the first indication was paid in the amount of $22.5 million as a result of the Investigational New Drug ("IND") application for EBI-031 becoming effective on or before September 15, 2016. In addition, the Company is entitled to receive royalty payments in accordance with a tiered royalty rate scale, with rates ranging from 7.5% to 15% for net sales of potential future products containing EBI-031 and up to 50% of these rates for net sales of potential future products containing other IL-6 compounds, with each of the royalties subject to reduction under certain circumstances and to the buy-out options of Roche further described below. Buy-Out Options The License Agreement provides for two “option periods” during which Roche may elect to make a one-time payment to the Company and, in turn, terminate its diligence, milestone and royalty payment obligations under the License Agreement. Specifically, (i) Roche may exercise a buy-out option following the first dosing (“Initiation”) in the first Phase 2 study for a Licensed Product until the day before Initiation of the first Phase 3 study for a Licensed Product, in which case Roche is required to pay the Company $135.0 million within 30 days after Roche's exercise of such buy-out option and receipt of an invoice from the Company, or (ii) Roche may exercise a buy-out option following the day after Initiation of the first Phase 3 study for a Licensed Product until the day before the acceptance for review by the U.S. Food and Drug Administration ("FDA") or other regulatory authority of a biologics license application (“BLA”) or similar application for marketing approval for a Licensed Product in either the United States or in the European Union, in which case Roche is required to pay the Company, within 30 days after Roche’s exercise of such buy-out option and receipt of an invoice from the Company, $265.0 million, which amount would be reduced to $220.0 million if none of the Company’s patent rights containing a composition of matter claim covering any compound or Licensed Product has issued in the European Union. Termination The Company or Roche may each terminate the License Agreement if the other party breaches any of its material obligations under the License Agreement and does not cure such breach within a specified cure period. Roche may terminate the License Agreement following effectiveness by providing advance written notice to the Company or by providing written notice if the Company is debarred, disqualified, suspended, excluded, or otherwise declared ineligible from certain federal or state agencies or programs. The Company may terminate the License Agreement if, prior to the first filing of a BLA for a Licensed Product, there is a period of 12 months where Roche is not conducting sufficient development activities with respect to the products made from the Licensed Intellectual Property. The Company’s License Agreement with Roche contains the following deliverables: 1) an exclusive, worldwide license, including the right to sublicense, to its patent and know-how related to the Company’s monoclonal antibody EBI-031 or any other IL-6 antagonist anti-IL-6 monoclonal antibody; 2) IND regulatory clearance activities; 3) conduct a tissue cross-reactivity study; 4) transfer pre-clinical inventory and 5) perform de minimus post-effective date services. The Company has determined that the License Agreement contains four units of accounting. The de minimis post-effective date services were not determined to be substantive, and thus were not considered units of accounting. The $29.9 million of allocable arrangement consideration was allocated to each of the units of accounting using the relative selling price method based on the Company’s best estimate of selling price of each of the units of accounting. The best estimate of selling price of the license was calculated using a discounted cash flow model that included the following key assumptions: the development timeline of EBI-031, future revenue forecast for EBI-031, and an appropriate discount rate to discount the related cash flows and probability of successful development. The best estimate of selling price of the remaining deliverables was based on estimated costs plus a reasonable margin. The allocation of arrangement consideration was not particularly sensitive to changes in the Company's best estimate of selling price given the significant value ascribed to the license deliverable. The Company recognizes arrangement consideration allocated to each unit of accounting when all of the revenue recognition criteria in ASC 605-25 are satisfied for that particular unit of accounting. As of December 31, 2016, the basic revenue recognition criteria has been met for all units of accounting except for the transfer of pre-clinical inventory. Accordingly, the Company recognized $29.6 million in revenue related to the License Agreement for the year ended December 31, 2016. The $0.4 million of revenue allocated to the transfer of pre-clinical inventory will be recognized upon delivery of the inventory to Roche. The Company determined that the milestone payments under the License Agreement were not subject to ASC 605-28 because the achievement of the milestone event depends solely on Roche’s performance. The Company will recognize royalty revenue in the period of sale of the related product(s), based on the underlying contract terms, provided that the reported sales are reliably measurable and the Company has no remaining performance obligations, assuming all other revenue recognition criteria are met.

License Agreement with Roche

On June 10, 2016, the Company entered into the License Agreement with Roche, which became effective on August 16, 2016. Under the License Agreement, the Company granted Roche an exclusive, worldwide license, including the right to sublicense, to its patent rights and know-how related to the Company’s monoclonal antibody EBI-031 or any other IL-6 antagonist anti-IL-6 monoclonal antibody, to make, have made, use, have used, register, have registered, sell, have sold, offer for sale, import and export any product containing such an antibody or any companion diagnostic used to predict or monitor response to treatment with such a product (collectively, the “Licensed Intellectual Property”).

Under the License Agreement, Roche is required to continue developing EBI-031 and any other product made from the Licensed Intellectual Property that contains an IL-6 antagonist anti-IL-6 monoclonal antibody (a “Licensed Product”) at its cost.

Financial Terms

The Company received an upfront license fee of $7.5 million from Roche and Roche agreed to pay up to an additional $262.5 million upon the achievement of specified regulatory, development and commercial milestones with respect to up to two unrelated indications. Specifically, an aggregate amount of up to $197.5 million is payable to the Company for the achievement of specified milestones with respect to the first indication: $72.5 million in development milestones, $50.0 million in regulatory milestones and $75.0 million in commercialization milestones. Additional amounts of up to $65.0 million are payable upon the achievement of specified development and regulatory milestones in a second indication.

The first development milestone payment for the first indication was paid in the amount of $22.5 million as a result of the Investigational New Drug ("IND") application for EBI-031 becoming effective on or before September 15, 2016.

In addition, the Company is entitled to receive royalty payments in accordance with a tiered royalty rate scale, with rates ranging from 7.5% to 15% for net sales of potential future products containing EBI-031 and up to 50% of these rates for net sales of potential future products containing other IL-6 compounds, with each of the royalties subject to reduction under certain circumstances and to the buy-out options of Roche further described below.

Buy-Out Options

The License Agreement provides for two “option periods” during which Roche may elect to make a one-time payment to the Company and, in turn, terminate its diligence, milestone and royalty payment obligations under the License Agreement. Specifically, (i) Roche may exercise a buy-out option following the first dosing (“Initiation”) in the first Phase 2 study for a Licensed Product until the day before Initiation of the first Phase 3 study for a Licensed Product, in which case Roche is required to pay the Company $135.0 million within 30 days after Roche's exercise of such buy-out option and receipt of an invoice from the Company, or (ii) Roche may exercise a buy-out option following the day after Initiation of the first Phase 3 study for a Licensed Product until the day before the acceptance for review by the U.S. Food and Drug Administration ("FDA") or other regulatory authority of a biologics license application (“BLA”) or similar application for marketing approval for a Licensed Product in either the United States or in the European Union, in which case Roche is required to pay the Company, within 30 days after Roche’s exercise of such buy-out option and receipt of an invoice from the Company, $265.0 million, which amount would be reduced to $220.0 million if none of the Company’s patent rights containing a composition of matter claim covering any compound or Licensed Product has issued in the European Union.

Termination

The Company or Roche may each terminate the License Agreement if the other party breaches any of its material obligations under the License Agreement and does not cure such breach within a specified cure period. Roche may terminate the License Agreement following effectiveness by providing advance written notice to the Company or by providing written notice if the Company is debarred, disqualified, suspended, excluded, or otherwise declared ineligible from certain federal or state agencies or programs. The Company may terminate the License Agreement if, prior to the first filing of a BLA for a Licensed Product, there is a period of 12 months where Roche is not conducting sufficient development activities with respect to the products made from the Licensed Intellectual Property.

The Company’s License Agreement with Roche contains the following deliverables: 1) an exclusive, worldwide license, including the right to sublicense, to its patent and know-how related to the Company’s monoclonal antibody EBI-031 or any other IL-6 antagonist anti-IL-6 monoclonal antibody; 2) IND regulatory clearance activities; 3) conduct a tissue cross-reactivity study; 4) transfer pre-clinical inventory and 5) perform de minimus post-effective date services.

The Company has determined that the License Agreement contains four units of accounting. The de minimis post-effective date services were not determined to be substantive, and thus were not considered units of accounting. The $29.9 million of allocable arrangement consideration was allocated to each of the units of accounting using the relative selling price method based on the Company’s best estimate of selling price of each of the units of accounting. The best estimate of selling price of the license was calculated using a discounted cash flow model that included the following key assumptions: the development timeline of EBI-031, future revenue forecast for EBI-031, and an appropriate discount rate to discount the related cash flows and probability of successful development. The best estimate of selling price of the remaining deliverables was based on estimated costs plus a reasonable margin. The allocation of arrangement consideration was not particularly sensitive to changes in the Company's best estimate of selling price given the significant value ascribed to the license deliverable.

The Company recognizes arrangement consideration allocated to each unit of accounting when all of the revenue recognition criteria in ASC 605-25 are satisfied for that particular unit of accounting. As of December 31, 2016, the basic revenue recognition criteria has been met for all units of accounting except for the transfer of pre-clinical inventory. Accordingly, the Company recognized $29.6 million in revenue related to the License Agreement for the year ended December 31, 2016. The $0.4 million of revenue allocated to the transfer of pre-clinical inventory will be recognized upon delivery of the inventory to Roche.

The Company determined that the milestone payments under the License Agreement were not subject to ASC 605-28 because the achievement of the milestone event depends solely on Roche’s performance. The Company will recognize royalty revenue in the period of sale of the related product(s), based on the underlying contract terms, provided that the reported sales are reliably measurable and the Company has no remaining performance obligations, assuming all other revenue recognition criteria are met.