Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.19.2
Summary of Significant Accounting Policies - Additional Information (Detail)
3 Months Ended 6 Months Ended
Jun. 30, 2019
USD ($)
Jun. 30, 2018
USD ($)
Jun. 30, 2019
USD ($)
Jun. 30, 2018
USD ($)
Jan. 01, 2019
USD ($)
Dec. 31, 2018
USD ($)
Summary Of Significant Accounting Policies [Line Items]            
Maturity period of highly liquid investments     Three months or less      
Realized gains or losses on marketable securities $ 0 $ 0 $ 0 $ 0    
Number of securities in unrealized loss position for more than 12 months 0   0     0
Grants receivable recognized $ 500,000 $ 1,200,000 $ 400,000 $ 800,000    
Grants receivable 600,000   600,000     $ 200,000
Grants remaining to be awarded 10,600,000   10,600,000      
Current portion of lease liabilities 625,541   625,541    
Long-term portion of lease liabilities 3,399,926   3,399,926    
Operating lease right-of use assets 3,150,932   3,150,932      
Operating lease liabilities $ 4,025,467   $ 4,025,467      
Adjustments due to the adoption of Topic 842            
Summary Of Significant Accounting Policies [Line Items]            
Current portion of lease liabilities         $ 600,000  
Long-term portion of lease liabilities         3,500,000  
Operating lease right-of use assets         3,300,000  
Operating lease liabilities         $ 4,100,000