Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.19.1
Summary of Significant Accounting Policies - Additional Information (Detail)
$ in Thousands
1 Months Ended 12 Months Ended
Aug. 31, 2013
USD ($)
Dec. 31, 2018
USD ($)
Segment
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Subsidiary, Sale of Stock [Line Items]        
Cash, cash equivalents, and restricted cash   $ 11,767 $ 11,469 $ 35,656
Upfront payment received $ 1,500      
Deferred revenue estimated performance period 70 months      
Revenue recognized from upfront payments   $ 257 257  
Operating segments (number) | Segment   1    
License and Service [Member]        
Subsidiary, Sale of Stock [Line Items]        
Revenue recognized from upfront payments   $ 300 $ 300  
Sales Agreement        
Subsidiary, Sale of Stock [Line Items]        
Deferred offering costs   $ 200    
Collaboration Revenue | R-Pharm, CJSC | Customer Concentration Risk        
Subsidiary, Sale of Stock [Line Items]        
Percentage of total revenue   100.00% 100.00%