Annual report pursuant to Section 13 and 15(d)

Stockholders' (Deficit) Equity - Initial Public Offering and Pipe Offerings (Details)

v3.20.4
Stockholders' (Deficit) Equity - Initial Public Offering and Pipe Offerings (Details) - USD ($)
12 Months Ended
Jun. 30, 2020
Oct. 10, 2019
Jun. 16, 2019
Feb. 19, 2019
Feb. 19, 2019
Feb. 19, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Issuance of common shares for IPO, net of costs (in shares)       2,172,591          
Stock issued during period (in dollars per share)       $ 5.00 $ 5.00 $ 5.00      
Proceeds from issuance of common stock     $ 9,500,000   $ 10,900,000   $ 32,046,000 $ 24,096,000  
Net proceeds from issuance of common stock         9,700,000        
Debt conversion, original amount         11,800,000        
Converted debt, shares issued (in shares)       6,825,391          
Amount of accrued dividends converted to common stock         $ 4,800,000        
Conversion of accrued dividends into common stock, shares issued (in shares)       954,696          
Shares vested (in shares)       127,500          
Common stock, shares outstanding (in shares)       14,613,000 14,613,000 14,613,000 21,189,943 16,932,184  
Percentage of stock ownership after conversion           4.99%      
Convertible debt       $ 47,800 $ 47,800 $ 47,800      
Convertible debt instrument, number of equity instruments       273,034   273,034      
Exercise price of warrants (in dollars per share)             $ 11.32 $ 10.97 $ 1.75
Number of shares of common stock to be called by each warrant (in shares)   533,775   452,081 452,081 452,081      
Warrants Issued in Private Investment in Public Equity Offering                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Proceeds from issuance of common stock   $ 6,300,000              
Exercise price of warrants (in dollars per share)   $ 12.88 $ 14.00            
Number of shares of common stock to be called by each warrant (in shares)     472,500            
Private Investment in Public Equity Offering                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Number of units issued   485,250 675,000            
Exercise price of warrants (in dollars per share)     $ 16.00            
Number of common stock per unit   1 1            
Number of warrants per unit   1.1 0.7            
Proceeds from warrant exercises     $ 8,600,000            
Proceeds From Private Investment In Public Equity Offering   $ 5,700,000              
June 2020 Offering                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Issuance of common shares for IPO, net of costs (in shares) 4,216,868                
Stock issued during period (in dollars per share) $ 8.30                
Proceeds from issuance of common stock $ 35,000,000.0                
Net proceeds from issuance of common stock $ 32,000,000.0                
Sale of stock, price per share (in usd per share) $ 7.719                
Conversion of Preferred Stock into Common Stock                  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                  
Incremental common shares attributable to dilutive effect of conversion of preferred stock       2,534,766