Collaborative Arrangements and Licensing Agreements, Biogen Idec (Neurology) (Details) (Biogen Idec [Member], Agreement entered into in December 2012 [Member], Neurology [Member], USD $)	1 Months Ended
	Dec. 31, 2012 Target	Sep. 30, 2014
Collaborative Arrangement and Licensing Agreement [Abstract]
Number of targets	3
Upfront fee recorded as deferred revenue	$ 30,000,000
Next prospective milestone		10,000,000
License fee and substantive milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payment receivable		259,000,000
Development milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payment receivable		59,000,000
Regulatory milestones [Member]
Collaborative Arrangement and Licensing Agreement [Abstract]
Maximum amount of payment receivable		$ 130,000,000