Collaborative and Other Research and Development Contracts - Additional Information (Detail) (USD $)
0 Months Ended 1 Months Ended 12 Months Ended 0 Months Ended 1 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended 1 Months Ended 12 Months Ended 1 Months Ended
Nov. 17, 2011
May 31, 2010
Dec. 31, 2013
UAB [Member]
Agreement
Feb. 24, 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, 2013
U.S. Department of Health and Human Services [Member]
Sep. 30, 2013
National Institute of Allergy and Infectious Diseases [Member]
Dec. 31, 2013
National Institute of Allergy and Infectious Diseases [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]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]                              
Collaborative agreement contract value           $ 102,661,000                  
Collaborative agreement period of agreement           4 years   5 years              
Collaborative agreement additional contract period         12 months                    
Collaborative agreement additional contract value       55,000,000 77,191,000                    
Collaborative agreement adjusted contract value             234,852,000                
Collaborative agreement initial payment               5,000,000              
Collaborative agreement contract value               22,000,000              
Collaborative agreement exercised options awarded                 7,500,000            
License fee received                   250,000          
Up-front payment receivable amount                     10,000,000        
Deferred revenue up-front payment receivable                     10,000,000        
Deferred revenue initiation of clinical trial payment received                     5,000,000        
Potential milestone payments receivable                         15,000,000    
Unamortized deferred revenue, related to Amended and Restated Agreement                       7,766,000      
Unamortized deferred expenses, related to Amended and Restated Agreement                       1,864,000      
Milestone payment minimum                             1,400,000
Milestone payment maximum                             4,000,000
Annual license fees minimum                             150,000
Annual license fees maximum                             500,000
Advance notice period for termination of agreement                             60 days
Reduction in the percentage of future payments   0.5                          
Stock issued during period value for modification of license agreement                           5,911,000  
Payments for modification of license agreement                           $ 90,000  
Royalty reduction percentage of net proceeds 0.5                            
Number of agreements     2                        
Period of agreement     25 years                        
Renewable period of agreement     5 years