Collaborations	6 Months Ended
Jun. 30, 2014
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaborations	(10) Collaborations (a) Collaboration with Abbott Molecular Inc. In May 2014, the Company entered into a collaboration with Abbott Molecular, Inc. (“Abbott Molecular”) for the development of a companion diagnostic that can be used to identify patients with the MYD88 L265P oncogenic mutation. Under the agreement, Abbott Molecular has agreed to develop the companion diagnostic to comply with the requirements of the U.S. Food and Drug Administration (“FDA”) Center for Devices and Radiological Health. The Company expects to pay approximately $6,700,000 in external development expenses over five years under the agreement to develop an assay as the prototype of the companion diagnostic, to validate the prototype during a Phase 2 clinical trial of IMO-8400, and to complete FDA regulatory requirements and launch activities of the resultant final version of the companion diagnostic. Such expenses are subject to increase if Abbott Molecular incurs additional expenses in order to meet unexpected material requirements or obligations not included in the agreement or if the Company is required to conduct additional or different clinical trials which result in Abbott Molecular incurring additional costs. The Company will not receive any revenues from future sales, if any, of the companion diagnostic. The Company expects to use the prototype companion diagnostic developed by Abbott Molecular in its ongoing Phase 1/2 clinical trial of IMO-8400 in patients with DLBCL beginning in the fourth quarter of 2014 and in future clinical trials of IMO-8400. The Company incurred $1,300,000 in expenses under the Abbott Molecular agreement through June 30, 2014. (b) Amendment to Exclusive License and Research Collaboration Agreement with Merck Sharp & Dohme Corp. In April 2014, the Company entered into an amendment to its exclusive license and research collaboration agreement with Merck Sharp & Dohme Corp. (formerly Merck & Co., Inc. (“Merck & Co.”)). Under the license and research collaboration agreement, which the Company entered into with Merck & Co. in December 2006, the Company had granted Merck & Co. worldwide exclusive rights to its TLR7, TLR8, and TLR9 agonists for use in combination with Merck & Co.’s therapeutic and prophylactic vaccines under development in the fields of cancer, infectious diseases, and Alzheimer’s disease. As a result of this amendment, Merck & Co.’s rights under the license and research collaboration agreement have been limited to specified TLR7, TLR8, and TLR9 agonists that Merck & Co. selected in January 2012, and the Company regained the rights to pursue its other independently discovered TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in the fields of cancer, infectious diseases and Alzheimer’s disease so that it now has the right to pursue its TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in all fields. Merck & Co.’s obligations under the agreement to pay the Company milestone payments and royalties continue in effect with respect to the specified TLR7, TLR8, and TLR9 agonists. However, in connection with this amendment, the Company agreed that, to the extent that the Company licenses to third parties any TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in the fields of cancer, infectious diseases and Alzheimer’s disease and receives income under such licenses, Merck & Co. may credit against any milestone payments and royalties it owes to the Company an amount equal to 15% of the license income received by the Company under the third-party licenses, up to a maximum of $60.0 million in credits.

(10) Collaborations

(a) Collaboration with Abbott Molecular Inc.

In May 2014, the Company entered into a collaboration with Abbott Molecular, Inc. (“Abbott Molecular”) for the development of a companion diagnostic that can be used to identify patients with the MYD88 L265P oncogenic mutation. Under the agreement, Abbott Molecular has agreed to develop the companion diagnostic to comply with the requirements of the U.S. Food and Drug Administration (“FDA”) Center for Devices and Radiological Health. The Company expects to pay approximately $6,700,000 in external development expenses over five years under the agreement to develop an assay as the prototype of the companion diagnostic, to validate the prototype during a Phase 2 clinical trial of IMO-8400, and to complete FDA regulatory requirements and launch activities of the resultant final version of the companion diagnostic. Such expenses are subject to increase if Abbott Molecular incurs additional expenses in order to meet unexpected material requirements or obligations not included in the agreement or if the Company is required to conduct additional or different clinical trials which result in Abbott Molecular incurring additional costs. The Company will not receive any revenues from future sales, if any, of the companion diagnostic. The Company expects to use the prototype companion diagnostic developed by Abbott Molecular in its ongoing Phase 1/2 clinical trial of IMO-8400 in patients with DLBCL beginning in the fourth quarter of 2014 and in future clinical trials of IMO-8400. The Company incurred $1,300,000 in expenses under the Abbott Molecular agreement through June 30, 2014.

(b) Amendment to Exclusive License and Research Collaboration Agreement with Merck Sharp & Dohme Corp.

In April 2014, the Company entered into an amendment to its exclusive license and research collaboration agreement with Merck Sharp & Dohme Corp. (formerly Merck & Co., Inc. (“Merck & Co.”)). Under the license and research collaboration agreement, which the Company entered into with Merck & Co. in December 2006, the Company had granted Merck & Co. worldwide exclusive rights to its TLR7, TLR8, and TLR9 agonists for use in combination with Merck & Co.’s therapeutic and prophylactic vaccines under development in the fields of cancer, infectious diseases, and Alzheimer’s disease. As a result of this amendment, Merck & Co.’s rights under the license and research collaboration agreement have been limited to specified TLR7, TLR8, and TLR9 agonists that Merck & Co. selected in January 2012, and the Company regained the rights to pursue its other independently discovered TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in the fields of cancer, infectious diseases and Alzheimer’s disease so that it now has the right to pursue its TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in all fields. Merck & Co.’s obligations under the agreement to pay the Company milestone payments and royalties continue in effect with respect to the specified TLR7, TLR8, and TLR9 agonists. However, in connection with this amendment, the Company agreed that, to the extent that the Company licenses to third parties any TLR7, TLR8, and TLR9 agonists for use as vaccine adjuvants in the fields of cancer, infectious diseases and Alzheimer’s disease and receives income under such licenses, Merck & Co. may credit against any milestone payments and royalties it owes to the Company an amount equal to 15% of the license income received by the Company under the third-party licenses, up to a maximum of $60.0 million in credits.