Collaborative Arrangements and Licensing Agreements, Alnylam Pharmaceuticals, Inc. (Details) (USD $)	3 Months Ended		9 Months Ended		1 Months Ended	9 Months Ended		127 Months Ended	12 Months Ended				3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Mar. 31, 2004 Alnylam [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2014 Alnylam [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2013 Alnylam [Member] Collaborations and Licensing Agreements [Member]	Sep. 30, 2014 Alnylam [Member] Collaborations and Licensing Agreements [Member]	Dec. 31, 2013 Alnylam [Member] Collaborations and Licensing Agreements [Member] Phase 3 [Member]	Sep. 30, 2014 Alnylam [Member] Collaborations and Licensing Agreements [Member] Pre-specified events [Member]	Sep. 30, 2014 Alnylam [Member] Collaborations and Licensing Agreements [Member] Development milestones [Member]	Sep. 30, 2014 Alnylam [Member] Collaborations and Licensing Agreements [Member] Regulatory milestones [Member]	Mar. 31, 2014 Alnylam [Member] Alnylam's collaboration with Genzyme [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Upfront fee received					$ 5,000,000
Maximum amount of payments receivable per drug under strategic alliance										3,400,000	1,100,000	2,300,000
Milestone payment earned									750,000
Next prospective milestone						375,000		375,000
Potential payments for drug development										3,400,000
Revenue earned	$ 44,063,000	$ 23,585,000	$ 129,300,000	$ 105,036,000		$ 7,700,000	$ 400,000	$ 48,200,000					$ 7,700,000