Annual report pursuant to Section 13 and 15(d)

Commitments and Contingencies - Additional Information (Detail)

Commitments and Contingencies - Additional Information (Detail)
1 Months Ended 12 Months Ended
Apr. 02, 2019
Jan. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Jan. 01, 2019
Loss Contingencies [Line Items]                
Non-cancellable operating lease, expiration date   2027-12   2025-12        
Extended lease agreement, date     2027-12          
Number of lease extension options | ExtensionOptions   2 2          
Lease renewal termination period   5 years 5 years          
Area of space relinquished from lease agreement | ft²   10,912            
Rent expense           $ 618,000 $ 587,000  
Operating lease, remaining lease term               9 years
Operating lease, discount rate, percent               9.93%
Gilman [Member] | Separation Agreements [Member]                
Loss Contingencies [Line Items]                
Percentage of bonus on last drawn salary 25.00%              
General and Administrative Expense [Member] | Supplemental Employee Retirement Plan [Member]                
Loss Contingencies [Line Items]                
Separation agreement date         Dec. 12, 2017      
Severance payments period following the effective date of retirement         18 months      
Agreement description         On December 12, 2017, the Company notified Lisa R. Ricciardi that she would no longer be needed to serve as Chief Operating Officer of the Company effective December 31, 2017. Subject to Ms. Ricciardi entering into a separation agreement, the Company accrued expense of $0.7 million for the severance payments and continued medical, dental and vision coverage under the Company’s group healthcare plans, to be provided for a period of 18 months following the effective date of Ms. Ricciardi’s termination, and recognized share-based compensation expense of $0.2 million for the accelerated vesting of all unvested portions of Ms. Ricciardi’s stock option grants. The total amount of these charges was recognized as part of general and administrative expenses in the consolidated statement of operations for the year ended December 31, 2017.      
Severance payment on effective date of retirement, as per the agreement         $ 700,000      
Share-based compensation expense         200,000      
Rockefeller University [Member]                
Loss Contingencies [Line Items]                
Annual maintenance fees payable in 2018         200,000      
Annual maintenance fees payable after 2018         $ 200,000      
Percentage of royalty on net sales         5.00%      
Milestone payment         $ 430,000 0 0  
Royalty or sublicense payment           $ 0 $ 0  
License agreement termination notice period         60 days      
Period of termination after first commercial sale of first licensed product         10 years      
License agreement termination description         Each license agreement terminates upon the later of (i) the expiration or abandonment of the last licensed patent under the license agreement to expire or become abandoned, or (ii) 10 years after the first commercial sale of the first licensed product. The Rockefeller University may terminate any license agreement in the event of a breach of such agreement by the Company or if the Company challenges the validity or enforceability of the underlying patent rights. The Company may terminate any license agreement at any time on 60 days’ notice.