Collaboration Agreements (Details) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Collaborative arrangements [Line Items]      
Contracts and grants revenue $ 54,823,000 $ 66,009,000 $ 70,975,000
Abbott Laboratories TRU016 [Member]
     
Collaborative arrangements [Line Items]      
Contracts and grants revenue   2,700,000 17,700,000
Recognition of deferred revenue   1,400,000 10,500,000
Revenue related to achievement of a development milestone     6,000,000
Revenues related to collaborative research funding   1,400,000 1,200,000
Pfizer CD20 [Member]
     
Collaborative arrangements [Line Items]      
Contracts and grants revenue   1,200,000 1,900,000
Recognition of deferred revenue   68,000 52,000
Revenues related to collaborative research funding   $ 1,100,000 $ 1,800,000