Collaborative Arrangements (Details 8) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Information related to collaborative arrangements
Total reduction to R&D expense	$ 6,996	$ 1,109	$ 839
GSK
Information related to collaborative arrangements
Total reduction to R&D expense	473	168	449
Merck
Information related to collaborative arrangements
Total reduction to R&D expense	4,937	756	0
Alfa Wassermann
Information related to collaborative arrangements
Total reduction to R&D expense	1,500	185	0
R-Pharm
Information related to collaborative arrangements
Total reduction to R&D expense	86	0	0
Astellas
Information related to collaborative arrangements
Total reduction to R&D expense	$ 0	$ 0	$ 390