Quarterly report pursuant to Section 13 or 15(d)

Capital Structure - Additional Information (Detail)

v3.21.2
Capital Structure - Additional Information (Detail)
9 Months Ended 12 Months Ended
Mar. 22, 2021
USD ($)
$ / shares
shares
May 27, 2020
USD ($)
$ / shares
shares
Jul. 25, 2017
USD ($)
Jul. 27, 2016
USD ($)
Sep. 30, 2021
USD ($)
shares
Sep. 30, 2020
USD ($)
Dec. 31, 2020
shares
Class of Stock [Line Items]              
Common stock, shares authorized | shares         125,000,000   125,000,000
Number of shares issued | shares   11,797,752          
Net proceeds received   $ 48,900,000          
Gross Proceed   $ 3,000,000.0          
Dividends declared or paid         $ 0    
Issuance costs allocated to warrants           $ 2,175,000  
Common stock, voting rights         The holders of shares of common stock are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings.    
Issuance of common stock for exercise of warrants, Shares | shares         22,560   5,850
2016 Warrants [Member]              
Class of Stock [Line Items]              
Warrants and rights outstanding maturity date         Jul. 27, 2021    
Private Placement [Member]              
Class of Stock [Line Items]              
Public offering price, per unit | $ / shares   $ 4.45          
Issuance of securities in private placement, Shares | shares   674,156          
Follow-on Offering [Member]              
Class of Stock [Line Items]              
Public offering price, per unit | $ / shares   $ 4.45          
Warrants to purchase shares of common stock | shares   8,848,314          
Warrant exercise price per share | $ / shares   $ 4.90          
Conversion ratio of common stock           0.75  
Follow-on Offering [Member] | 2016 Warrants [Member]              
Class of Stock [Line Items]              
Fair value of warrants       $ 18,600,000      
Issuance costs allocated to warrants       $ 1,600,000      
Follow-on Offering [Member] | 2017 Warrants [Member]              
Class of Stock [Line Items]              
Fair value of warrants     $ 12,400,000        
Issuance costs allocated to warrants     $ 900,000        
Follow-on Offering [Member] | 2020 Warrants [Member]              
Class of Stock [Line Items]              
Fair value of warrants   $ 31,400,000          
Issuance costs allocated to warrants   $ 2,200,000          
Over-Allotment Option [Member]              
Class of Stock [Line Items]              
Number of shares issued | shares 11,500,000            
Proceeds from initial public offer $ 53,800,000            
Sale of stock issue price per share | $ / shares $ 5.00            
Pfizer Warrants [Member]              
Class of Stock [Line Items]              
Warrants to purchase shares of common stock | shares   505,617          
Warrant exercise price per share | $ / shares   $ 4.90