XML 40 R29.htm IDEA: XBRL DOCUMENT v3.21.2
Common Stock and Warrants - Additional Information (Details) - USD ($)
 1 Months Ended 3 Months Ended 9 Months Ended
Sep. 30, 2021
Sep. 01, 2021
Feb. 01, 2021
Oct. 26, 2020
Mar. 20, 2020
Jan. 27, 2020
Mar. 31, 2020
Sep. 30, 2021
Jun. 30, 2021
Mar. 31, 2021
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Schedule Of Stockholders Equity [Line Items]                          
Common stock, shares authorized 150,000,000             150,000,000     150,000,000   150,000,000
Common stock, par value $ 0.001             $ 0.001     $ 0.001   $ 0.001
Preferred stock, shares authorized 10,000,000             10,000,000     10,000,000   10,000,000
Preferred stock, par value $ 0.001             $ 0.001     $ 0.001   $ 0.001
Common share, voting rights                     one vote per share    
Common share, dividends declared                     $ 0    
Gross proceeds from issuance of common stock                     $ 11,614,000 $ 7,233,000  
Minimum | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Average price of sale of common stock   $ 15.1661                      
Maximum | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Issuance of common stock outstanding percentage   19.99%                      
Common Stock | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Shares issued               40,000          
Net proceeds from issuance of common stock               $ 600,000          
Agreement term   36 months                      
Number of shares issued for commitment fee               31,958          
Fair value of commitment fee               $ 500,000          
Number of shares issuable in transaction   20,000                      
Common Stock | Minimum | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Beneficially owned percentage   9.99%                      
Common Stock | Maximum | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Long-term purchase commitment amount   $ 15,000,000.0                      
Consideration receivable per transaction   $ 2,000,000.0                      
2020 ATM                          
Schedule Of Stockholders Equity [Line Items]                          
Gross proceeds from issuance of common stock                       $ 5,000,000.0  
Price per share                       $ 21.68  
Offering expenses incurred                       $ 181,000  
2020 ATM | Common Stock                          
Schedule Of Stockholders Equity [Line Items]                          
Shares issued                       2  
2020 ATM | Form S3 Shelf Registration                          
Schedule Of Stockholders Equity [Line Items]                          
Aggregate offering amount           $ 11,340,000 $ 9,150,000            
March 2020 Offering                          
Schedule Of Stockholders Equity [Line Items]                          
Gross proceeds from issuance of common stock         $ 2,200,000                
Price per share         $ 12.25                
Warrants to purchase number of common stock, shares         178,776                
Warrant exercisable price per share         $ 16.10                
Underwriting discounts and commissions paid         $ 300,000                
Number of common stock converted by each warrant         1                
Warrants expiration date         Mar. 20, 2025                
Fair value of warrants at issuance         $ 800,000                
Class of warrants exercised 81,633                        
Proceeds from the exercise of warrants                   $ 1,300,000      
March 2020 Offering | Common Stock                          
Schedule Of Stockholders Equity [Line Items]                          
Shares issued         178,776                
October 2020 Offering                          
Schedule Of Stockholders Equity [Line Items]                          
Shares issued       187,646                  
Gross proceeds from issuance of common stock       $ 3,400,000                  
Price per share       $ 18.20                  
Warrants to purchase number of common stock, shares       93,817                  
Warrant exercisable price per share       $ 15.82                  
Fair value of warrants at issuance       $ 600,000                  
Share issuance cost including placement agent fees       $ 300,000                  
Warrants expiration period       3 years                  
Percentage of right to participate subsequent financing       30.00%                  
October 2020 Offering | Minimum                          
Schedule Of Stockholders Equity [Line Items]                          
Subscription to participate subsequent financing       $ 250,000                  
October 2020 Offering | Officer, Affiliates of an Officer and Director                          
Schedule Of Stockholders Equity [Line Items]                          
Price per share       $ 18.354                  
Warrant exercisable price per share       $ 16.1665                  
October 2020 Offering | Placement Agent                          
Schedule Of Stockholders Equity [Line Items]                          
Shares issued       961                  
Price per share       $ 19.775                  
October 2020 Offering | Common Stock                          
Schedule Of Stockholders Equity [Line Items]                          
Number of common stock converted by each warrant       0.50                  
Common unit issued       1                  
February 2021 Offering                          
Schedule Of Stockholders Equity [Line Items]                          
Price per share     $ 14.82                    
Warrants to purchase number of common stock, shares     372,468                    
Warrant exercisable price per share     $ 16.302                    
Number of common stock converted by each warrant     0.50                    
Fair value of warrants at issuance     $ 2,600,000                    
Class of warrants exercised 262                        
Proceeds from the exercise of warrants                 $ 4,000        
Warrants expiration period     5 years                    
Net proceeds from issuance of common stock     $ 9,600,000                    
February 2021 Offering | Common Stock                          
Schedule Of Stockholders Equity [Line Items]                          
Shares issued     744,936                    
Over-Allotment Option                          
Schedule Of Stockholders Equity [Line Items]                          
Price per share     $ 18.525                    
Over-Allotment Option | Common Stock                          
Schedule Of Stockholders Equity [Line Items]                          
Shares issued     29,797                    
Closing Sale Price 1 | Common Stock | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Price per share   $ 20.00                      
Closing Sale Price 1 | Common Stock | Maximum | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Number of shares issuable in transaction   25,000                      
Closing Sale Price 2 | Common Stock | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Price per share   $ 25.00                      
Closing Sale Price 2 | Common Stock | Maximum | LPC Purchase Agreement | Lincoln Park                          
Schedule Of Stockholders Equity [Line Items]                          
Number of shares issuable in transaction   30,000                      
Class A Common Stock                          
Schedule Of Stockholders Equity [Line Items]                          
Common stock, shares authorized 150,000,000             150,000,000     150,000,000    
Common stock, par value $ 0.001             $ 0.001     $ 0.001