Collaborative and Other Research and Development Contracts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended	1 Months Ended				12 Months Ended	1 Months Ended		12 Months Ended		1 Months Ended			12 Months Ended
	Dec. 31, 2012	Nov. 30, 2012 U.S. Department of Health and Human Services [Member] Sample	Feb. 28, 2011 U.S. Department of Health and Human Services [Member]	Sep. 30, 2009 U.S. Department of Health and Human Services [Member]	Jan. 31, 2007 U.S. Department of Health and Human Services [Member]	Dec. 31, 2012 U.S. Department of Health and Human Services [Member]	Jun. 30, 2006 Green Cross Corporation [Member]	Feb. 28, 2006 Mundipharma International Holdings Limited [Member]	Dec. 31, 2012 Mundipharma International Holdings Limited [Member]	Nov. 11, 2011 Mundipharma International Holdings Limited [Member]	May 31, 2010 AECOM and IRL [Member]	Jun. 30, 2000 AECOM and IRL [Member]	May 31, 2010 UAB [Member]	Dec. 31, 2012 UAB [Member] Agreement
Collaborative and Other Research and Development Contracts (Textual) [Abstract]
Collaborative agreement contract value					$ 102,661
Collaborative agreement period of agreement					4 years
Collaborative agreement additional contract period				12 months
Collaborative agreement additional contract value			55,000	77,191
Collaborative agreement adjusted contract value						234,852
Collaborative agreement planned interim analysis sample size		320
Contract term						24 months
Up-front payment receivable amount								10,000
Deferred revenue up-front payment receivable								10,000
License fee received							250
Deferred revenue initiation of clinic trail payment received								5,000
Potential milestone payments receivable										15,000
Unamortized deferred revenue, related to Amended and Restated Agreement									7,766
Unamortized deferred expenses, related to Amended and Restated Agreement									1,864
Advance notice period for termination of agreement												60 days
Milestone payment minimum												1,400
Milestone payment maximum												4,000
Annual license fees minimum												150
Annual license fees maximum												500
Stock issued during period value for modification of license agreement											5,911
Payments for modification of license agreement											$ 90
Period of agreement													25 years
Number of agreements														2
Renewable period of agreement													5 years
Royalty reduction percentage of net proceeds	0.50%