SUBSEQUENT EVENT	9 Months Ended
Sep. 30, 2015
Subsequent Events [Abstract]
SUBSEQUENT EVENT	SUBSEQUENT EVENT On November 2, 2015, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”), with Shire Pharmaceuticals International, a company incorporated in Ireland (“Parent”), Parquet Courts, Inc., a Delaware corporation and a wholly-owned subsidiary of Parent (“Merger Sub”) and Shire plc, a company incorporated in Jersey (“Parent Holdco”). Upon the terms and subject to the conditions set forth in the Merger Agreement, Merger Sub will be merged with and into Dyax and the separate corporate existence of Merger Sub will thereupon cease, pursuant to the provisions of the General Corporation Law of the State of Delaware (DGCL), as provided in the Merger Agreement, with Dyax being the surviving corporation (the “Merger”). Parent Holdco has guaranteed the performance by Parent and Merger Sub of their obligations under the Merger Agreement. At the effective time of the Merger (the “Effective Time”), each issued and outstanding share of the common stock of Dyax will be cancelled and converted into the right to receive (a) $37.30 per share in cash, subject to any applicable withholding of taxes, without interest and (b) one (1) contractual contingent value right per share (each, a “CVR”), which represents the right to receive a contingent payment of $4.00 in cash, without interest, if the specified milestone is achieved, pursuant to a Contingent Value Rights Agreement (the “CVR Agreement”) to be entered into between Parent Holdco and a rights agent. The completion of the Merger is subject to adoption of the Merger Agreement by holders of a majority of the outstanding shares of Dyax entitled to vote on the matter, the expiration of the waiting period (and any extension thereof) under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (the “HSR Act”) and other customary closing conditions. Parent Holdco has agreed to use reasonable best efforts to obtain antitrust approval of the transaction, but is not obligated to divest any assets other than assets of Dyax aggregating no greater than $77.0 million in revenue for 2014. Consummation of the Merger is not subject to a financing condition. The Company and Parent may terminate the Merger Agreement if the Merger is not consummated by August 2, 2016, which date may be extended to November 2, 2016 under certain circumstances described in the Merger Agreement. The Merger Agreement includes customary representations, warranties and covenants by the Company, Parent, Merger Sub and Parent Holdco. The Company has agreed to operate its business in the ordinary course until the Effective Time. The Company has also agreed not to solicit or initiate discussions with third parties regarding other proposals to acquire it and to certain restrictions on its ability to respond to any such proposals. The Merger Agreement also includes customary termination provisions for both the Company and Parent, subject, in certain circumstances, to (a) the payment by the Company of a termination fee of $180 million (the “Company Termination Fee”) or (b) the payment by Parent of a termination fee of $280 million (the “Parent Termination Fee”). The Company must pay Parent the Company Termination Fee in the event that the Merger Agreement is terminated by Parent following a change of recommendation by the Company’s board of directors or if the Company enters into an agreement with respect to a proposal from a third party that is superior to Parent’s, in each case, as is more particularly described in the Merger Agreement. Under certain additional circumstances described in the Merger Agreement, the Company must also pay Parent the Company Termination Fee if the Merger Agreement is terminated and, within 12 months following such termination, the Company enters into an agreement for a business combination transaction of the type described in the relevant provisions of the Merger Agreement and such transaction is subsequently consummated. The Company is also required to reimburse Parent for documented out-of-pocket expenses of up to a maximum of $15 million under circumstances specified in the Merger Agreement. Any payment of such expenses to Parent will be credited against any Company Termination Fee paid to Parent by the Company. Parent must pay the Company the Parent Termination Fee in certain circumstances specified in the Merger Agreement where the required antitrust approval is not obtained. The parties to the Merger Agreement are also entitled to an injunction or injunctions to prevent breaches of the Merger Agreement, and to specifically enforce the terms and provisions of the Merger Agreement. The Company’s board of directors unanimously (i) approved and declared advisable the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, upon the terms and subject to the conditions set forth in the Merger Agreement, (ii) determined that the Merger Agreement and such transactions are fair to, and in the best interests of, Dyax and its stockholders (other than Parent Holdco, Parent and its subsidiaries) and (iii) resolved to recommend that Dyax’s stockholders approve the adoption of the Merger Agreement. Prior to consummation of the Merger, Parent Holdco will enter into the CVR Agreement with a rights agent mutually agreeable to Parent Holdco and Dyax governing the terms of the CVR portion of the merger consideration. Each CVR represents the right to receive a contingent payment of $4.00 in cash, without interest, upon receipt, prior to December 31, 2019, of approval from the U.S. Food and Drug Administration (“FDA”) of a biologic license application for DX-2930 that does not require, among other things, the inclusion of a “boxed warning” (as defined in 21 CFR §201.57(c)(1)) in the product labeling and the implementation of a risk evaluation and mitigation strategy with elements to assure safe use required by the FDA (other than elements limited to the distribution of educational materials). This approval would grant the right to market and sell DX-2930 in the United States in accordance with applicable law for the prevention of attacks of Type 1 and Type 2 hereditary angioedema in patients with Type 1 or Type 2 hereditary angioedema. The right to the CVR portion of the merger consideration as evidenced by the CVR Agreement is a contractual right only and will not be transferable, except in the limited circumstances specified in the CVR Agreement.

SUBSEQUENT EVENT

On November 2, 2015, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”), with Shire Pharmaceuticals International, a company incorporated in Ireland (“Parent”), Parquet Courts, Inc., a Delaware corporation and a wholly-owned subsidiary of Parent (“Merger Sub”) and Shire plc, a company incorporated in Jersey (“Parent Holdco”). Upon the terms and subject to the conditions set forth in the Merger Agreement, Merger Sub will be merged with and into Dyax and the separate corporate existence of Merger Sub will thereupon cease, pursuant to the provisions of the General Corporation Law of the State of Delaware (DGCL), as provided in the Merger Agreement, with Dyax being the surviving corporation (the “Merger”). Parent Holdco has guaranteed the performance by Parent and Merger Sub of their obligations under the Merger Agreement.

At the effective time of the Merger (the “Effective Time”), each issued and outstanding share of the common stock of Dyax will be cancelled and converted into the right to receive (a) $37.30 per share in cash, subject to any applicable withholding of taxes, without interest and (b) one (1) contractual contingent value right per share (each, a “CVR”), which represents the right to receive a contingent payment of $4.00 in cash, without interest, if the specified milestone is achieved, pursuant to a Contingent Value Rights Agreement (the “CVR Agreement”) to be entered into between Parent Holdco and a rights agent.

The completion of the Merger is subject to adoption of the Merger Agreement by holders of a majority of the outstanding shares of Dyax entitled to vote on the matter, the expiration of the waiting period (and any extension thereof) under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (the “HSR Act”) and other customary closing conditions. Parent Holdco has agreed to use reasonable best efforts to obtain antitrust approval of the transaction, but is not obligated to divest any assets other than assets of Dyax aggregating no greater than $77.0 million in revenue for 2014. Consummation of the Merger is not subject to a financing condition. The Company and Parent may terminate the Merger Agreement if the Merger is not consummated by August 2, 2016, which date may be extended to November 2, 2016 under certain circumstances described in the Merger Agreement.

The Merger Agreement includes customary representations, warranties and covenants by the Company, Parent, Merger Sub and Parent Holdco. The Company has agreed to operate its business in the ordinary course until the Effective Time. The Company has also agreed not to solicit or initiate discussions with third parties regarding other proposals to acquire it and to certain restrictions on its ability to respond to any such proposals. The Merger Agreement also includes customary termination provisions for both the Company and Parent, subject, in certain circumstances, to (a) the payment by the Company of a termination fee of $180 million (the “Company Termination Fee”) or (b) the payment by Parent of a termination fee of $280 million (the “Parent Termination Fee”). The Company must pay Parent the Company Termination Fee in the event that the Merger Agreement is terminated by Parent following a change of recommendation by the Company’s board of directors or if the Company enters into an agreement with respect to a proposal from a third party that is superior to Parent’s, in each case, as is more particularly described in the Merger Agreement. Under certain additional circumstances described in the Merger Agreement, the Company must also pay Parent the Company Termination Fee if the Merger Agreement is terminated and, within 12 months following such termination, the Company enters into an agreement for a business combination transaction of the type described in the relevant provisions of the Merger Agreement and such transaction is subsequently consummated. The Company is also required to reimburse Parent for documented out-of-pocket expenses of up to a maximum of $15 million under circumstances specified in the Merger Agreement. Any payment of such expenses to Parent will be credited against any Company Termination Fee paid to Parent by the Company. Parent must pay the Company the Parent Termination Fee in certain circumstances specified in the Merger Agreement where the required antitrust approval is not obtained. The parties to the Merger Agreement are also entitled to an injunction or injunctions to prevent breaches of the Merger Agreement, and to specifically enforce the terms and provisions of the Merger Agreement.

The Company’s board of directors unanimously (i) approved and declared advisable the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, upon the terms and subject to the conditions set forth in the Merger Agreement, (ii) determined that the Merger Agreement and such transactions are fair to, and in the best interests of, Dyax and its stockholders (other than Parent Holdco, Parent and its subsidiaries) and (iii) resolved to recommend that Dyax’s stockholders approve the adoption of the Merger Agreement.

Prior to consummation of the Merger, Parent Holdco will enter into the CVR Agreement with a rights agent mutually agreeable to Parent Holdco and Dyax governing the terms of the CVR portion of the merger consideration. Each CVR represents the right to receive a contingent payment of $4.00 in cash, without interest, upon receipt, prior to December 31, 2019, of approval from the U.S. Food and Drug Administration (“FDA”) of a biologic license application for DX-2930 that does not require, among other things, the inclusion of a “boxed warning” (as defined in 21 CFR §201.57(c)(1)) in the product labeling and the implementation of a risk evaluation and mitigation strategy with elements to assure safe use required by the FDA (other than elements limited to the distribution of educational materials). This approval would grant the right to market and sell DX-2930 in the United States in accordance with applicable law for the prevention of attacks of Type 1 and Type 2 hereditary angioedema in patients with Type 1 or Type 2 hereditary angioedema. The right to the CVR portion of the merger consideration as evidenced by the CVR Agreement is a contractual right only and will not be transferable, except in the limited circumstances specified in the CVR Agreement.