Annual report pursuant to Section 13 and 15(d)

Milestones and Sponsored Research Agreements - Additional Information (Detail)

v3.8.0.1
Milestones and Sponsored Research Agreements - Additional Information (Detail) - USD ($)
 1 Months Ended 12 Months Ended
Jul. 03, 2017
Nov. 28, 2017
Jun. 30, 2017
Feb. 17, 2017
Mar. 31, 2016
Feb. 29, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Oct. 31, 2016
Mar. 31, 2015
Research And Development Expense             $ 52,486,000 $ 35,134,000 $ 29,810,000    
Payments To Acquire In Process Research And Development             3,365,000 3,785,000 10,448,000    
Reimbursement Of Cost Recognized As Revenue             600,000 1,000,000      
SPR Sponsored Research Agreement [Member]                      
Research And Development Expense             100,000        
Revenue Recognition Milestone Method Payments Due Over Three Years   $ 800,000                  
Checkpoint Therapeutics, Inc [Member]                      
Stock Issued During Period, Value, Purchase of Assets             22,000,000        
AR CD123 License [Member]                      
Revenue Recognition Milestone Method Payments Due Over Three Years       $ 200,000              
Pep Vax [Member]                      
Payments For Research And Development Expenses             1,100,000 2,500,000 0    
Triplex [Member]                      
Payments For Research And Development Expenses             2,600,000 1,800,000 0    
Helocyte Inc [Member]                      
Payments For Research And Development Expenses             3,700,000 4,300,000 0    
Helocyte Inc [Member] | Pentamer Sponsored Research Agreement [Member]                      
Payment of Upfront Fees     $ 1,500,000       200,000 0      
Mustang Bio, Inc [Member]                      
Research And Development Expense Payable Milestone Payment       200,000     2,000,000 2,000,000 $ 1,500,000   $ 2,000,000
Research And Development Expense             600,000        
Payment of Upfront Fees       9,300,000,000              
Revenue Recognition Milestone Method Payments Due       100,000              
Mustang Bio, Inc [Member] | AR IL-13 License [Member]                      
Research And Development Expense             1,400,000        
Mustang Bio, Inc [Member] | CD20 Technology License [Member]                      
Payment of Upfront Fees $ 5,300,000                    
UCLB [Member]                      
Payment of Upfront Fees             $ 100,000        
Milestone Payments         $ 400,000            
UCLB [Member] | Minimum [Member]                      
Royalty Percentage             3.00%        
UCLB [Member] | Maximum [Member]                      
Royalty Percentage             5.00%        
Cellvation [Member]                      
Research And Development Expense Payable Milestone Payment                   $ 800,000  
Research And Development Expense             $ 100,000 $ 200,000      
City Of Hope [Member]                      
Research And Development Expense Payable Milestone Payment         2,000,000 $ 3,400,000          
Payments To Acquire In Process Research And Development         $ 1,000,000 $ 1,000,000          
City Of Hope [Member] | AR CD123 License [Member]                      
Research And Development Expense             $ 1,100,000        
Payment of Upfront Fees       20,000,000,000              
Revenue Recognition Milestone Method Payments Due       $ 100,000