Quarterly report pursuant to Section 13 or 15(d)

Milestones and Sponsored Research Agreements - Additional Information (Detail)

v3.5.0.2
Milestones and Sponsored Research Agreements - Additional Information (Detail) - USD ($)
$ in Thousands
1 Months Ended 3 Months Ended 6 Months Ended
Mar. 31, 2016
Feb. 29, 2016
Jun. 30, 2016
Jun. 30, 2015
Jun. 30, 2016
Jun. 30, 2015
Milestones and Sponsored Research Agreements [Line Items]            
Research And Development Expense     $ 6,347 $ 2,411 $ 14,100 $ 4,066
Helocyte Inc [Member]            
Milestones and Sponsored Research Agreements [Line Items]            
Research and Development Expense Payable, Milestone Payment     0   0  
Mustang Bio, Inc [Member]            
Milestones and Sponsored Research Agreements [Line Items]            
Research And Development Expense     500   1,000  
Research and Development Expense Payable, Milestone Payment     2,000   2,000  
UCLB [Member]            
Milestones and Sponsored Research Agreements [Line Items]            
Research and Development Expense Payable, Milestone Payment     $ 22,000   22,000  
Milestone Payments         400  
Payment of Upfront Fees         $ 100  
UCLB [Member] | Maximum [Member]            
Milestones and Sponsored Research Agreements [Line Items]            
Royalty Percentage         5.00%  
UCLB [Member] | Minimum [Member]            
Milestones and Sponsored Research Agreements [Line Items]            
Royalty Percentage         3.00%  
City Of Hope [Member]            
Milestones and Sponsored Research Agreements [Line Items]            
Payments to Acquire in Process Research and Development $ 1,000 $ 1,000        
Research and Development Expense Payable, Milestone Payment $ 2,000 $ 3,400