Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Additional information (Details)

v3.21.1
Stockholders' Equity - Additional information (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 12 Months Ended
Oct. 31, 2020
Sep. 30, 2020
Jan. 31, 2020
Oct. 31, 2019
Aug. 31, 2019
Apr. 30, 2019
Sep. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Class of Warrant or Right [Line Items]                  
Net proceeds               $ 8,900  
Issuance of common stock, net               $ 10,194 $ 8,237
Class of Warrant or Right, Number of Securities Called by Warrants or Rights               1,112,313  
Finance costs for issuance of warrants               $ 211 0
Class of Warrant or Right, Outstanding               2,437,000  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross               2,000  
Proceeds from Warrant Exercises               $ 7,243 $ 1,603
Issuance of common stock upon exercises of warrants, net (in shares)               450,761  
Common Stock                  
Class of Warrant or Right [Line Items]                  
Issuance of common stock, net (in shares)               3,605,000 1,257,000
Issuance of common stock, net               $ 4 $ 1
Issuance of common stock upon exercises of warrants, net (in shares)               1,563,000 207,000
Warrant                  
Class of Warrant or Right [Line Items]                  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights               1,022,408  
October 2020 Offering                  
Class of Warrant or Right [Line Items]                  
Number of units issued 2,666,667                
Shares Issued, Price Per Share $ 3.00                
Number of shares that each unit entitles 1                
Number of warrant that each unit entitles 1                
Number of shares that each warrant entitles 1                
Proceeds from sale of common stock $ 8,000                
Underwriting discounts and commissions 1,600                
Net proceeds $ 5,700                
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 3.00                
September 2020 Offering                  
Class of Warrant or Right [Line Items]                  
Shares Issued, Price Per Share   $ 4.20         $ 4.20    
Proceeds from sale of common stock   $ 2,400              
Issuance of common stock, net (in shares)   648,000              
January 2020 Offering                  
Class of Warrant or Right [Line Items]                  
Proceeds from sale of common stock     $ 1,900            
Class of Warrant or Right, Exercise Price of Warrants or Rights     $ 7.50            
Issuance of common stock, net (in shares)     290,000            
Class of Warrant or Right, Number of Securities Called by Warrants or Rights     290,000            
Finance costs for issuance of warrants             $ 200    
October 2019 Offering                  
Class of Warrant or Right [Line Items]                  
Shares Issued, Price Per Share       $ 6.75          
Issuance of common stock, net (in shares)       1,342,534          
October 2019 Offering | Common Stock                  
Class of Warrant or Right [Line Items]                  
Issuance of common stock, net (in shares)       1,196,200          
October 2019 Offering | Pre-Funded Warrants [Member] | Common Stock                  
Class of Warrant or Right [Line Items]                  
Class of Warrant or Right, Exercise Price of Warrants or Rights       $ 0.30          
Class of Warrant or Right, Number of Securities Called by Warrants or Rights       146,334          
October 2019 Offering | Placement Warrants | Class B Units [Member]                  
Class of Warrant or Right [Line Items]                  
Class of Warrant or Right, Exercise Price of Warrants or Rights       $ 6.75          
Class of Warrant or Right, Number of Securities Called by Warrants or Rights       1,342,534          
August 2019 Offering | Common Stock                  
Class of Warrant or Right [Line Items]                  
Class of Warrant or Right, Exercise Price of Warrants or Rights         $ 32.10        
Issuance of common stock, net (in shares)         49,334        
Class of Warrant or Right, Number of Securities Called by Warrants or Rights         95,078        
August 2019 Offering | Pre-Funded Warrants [Member] | Common Stock                  
Class of Warrant or Right [Line Items]                  
Class of Warrant or Right, Exercise Price of Warrants or Rights         $ 0.30        
Class of Warrant or Right, Number of Securities Called by Warrants or Rights         45,744        
August 2019 Offering | Placement Warrants | Common Stock                  
Class of Warrant or Right [Line Items]                  
Class of Warrant or Right, Exercise Price of Warrants or Rights         $ 32.10        
Class of Warrant or Right, Number of Securities Called by Warrants or Rights         95,078        
ATM                  
Class of Warrant or Right [Line Items]                  
Shares Issued, Price Per Share                 $ 48.00
Proceeds from sale of common stock                 $ 500
Issuance of common stock, net (in shares)                 10,989
ATM | Maximum                  
Class of Warrant or Right [Line Items]                  
Issuance of common stock, net     $ 800   $ 4,000 $ 8,600