Annual report pursuant to Section 13 and 15(d)

Note 17 - Subsequent Events (Details Textual)

v3.20.4
Note 17 - Subsequent Events (Details Textual) - USD ($)
1 Months Ended
Jan. 19, 2021
Jan. 01, 2021
Jun. 30, 2021
Mar. 17, 2021
Jan. 31, 2021
Jan. 31, 2020
Jan. 31, 2019
Jan. 18, 2021
Dec. 31, 2020
Apr. 20, 2020
Apr. 15, 2020
Jan. 01, 2020
Dec. 31, 2019
Nov. 26, 2019
Jan. 01, 2019
Dec. 31, 2018
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)                         2,473,785      
Sublease Agreement for Relocation of Headquarters [Member] | Forecast [Member]                                
Lessee, Operating Lease, Rent Abatement     $ 19,000                          
The 2013 Plan [Member]                                
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)           263,993 2,044                  
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)                 1,451,246     1,451,246   1,187,253 6,958 4,914
Series A-2 and Series B-2 Warrants [Member]                                
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                   $ 6.371            
Warrants and Rights Outstanding, Term (Year)                   5 years            
Series A and Series B Warrants [Member]                                
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)                     $ 6.10   $ 15.50      
Subsequent Event [Member] | Sublease Agreement for Relocation of Headquarters [Member]                                
Lessee, Operating Lease, Renewal Term (Month)       2 years 300 days                        
Subsequent Event [Member] | Sublease Agreement for Relocation of Headquarters First Year Extension [Member]                                
Lessee, Operating Lease, Monthly Gross Rent       $ 21,028                        
Subsequent Event [Member] | Sublease Agreement for Relocation of Headquarters Second Year Extension [Member]                                
Lessee, Operating Lease, Monthly Gross Rent       21,643                        
Subsequent Event [Member] | Sublease Agreement for Relocation of Headquarters Third Year Extension [Member]                                
Lessee, Operating Lease, Monthly Gross Rent       $ 22,258                        
Subsequent Event [Member] | Restricted Stock Units (RSUs) [Member]                                
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in shares)         690,000                      
Subsequent Event [Member] | The 2013 Plan [Member]                                
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)   307,705                            
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)   1,758,951                            
Subsequent Event [Member] | Series C Preferred Stock [Member]                                
Preferred Stock, Shares Outstanding, Ending Balance (in shares)         0                      
Subsequent Event [Member] | Series A-2 and Series B-2 Warrants [Member]                                
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) 1                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) $ 3.40             $ 6.371                
Subsequent Event [Member] | Series A and Series B Warrants [Member]                                
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) $ 3.40             $ 6.10                
Subsequent Event [Member] | Class A Units [Member] | Warrants Issued in Connection with Class A Units [Member]                                
Warrants Per Unit (in shares) 1                              
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) 1                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) $ 3.40                              
Warrants and Rights Outstanding, Term (Year) 5 years                              
Subsequent Event [Member] | Class B Units [Member] | Warrants Issued in Connection with Class B Units [Member]                                
Warrants Per Unit (in shares) 1                              
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares) 1                              
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) $ 3.40                              
Warrants and Rights Outstanding, Term (Year) 5 years                              
January 2021 Offering [Member] | Subsequent Event [Member]                                
Proceeds from Issuance or Sale of Equity, Total $ 27,600,000                              
Shares Issued, Price Per Share (in dollars per share) $ 3.40                              
Proceeds from Issuance or Sale of Equity, Net of Issuance Costs $ 25,223,000                              
January 2021 Offering [Member] | Subsequent Event [Member] | Series C Preferred Stock [Member]                                
Stock Issued During Period, Shares, New Issues (in shares) 2,450,880                              
Convertible Preferred Stock, Shares Issued upon Conversion (in shares) 1                              
January 2021 Offering [Member] | Subsequent Event [Member] | Class A Units [Member]                                
Units Issued, Shares (in shares) 4,607,940                              
Shares Issued, Price Per Share (in dollars per share) $ 3.40                              
Common Shares Per Unit (in shares) 1                              
January 2021 Offering [Member] | Subsequent Event [Member] | Class B Units [Member]                                
Units Issued, Shares (in shares) 2,450,880                              
Shares Issued, Price Per Share (in dollars per share) $ 3.40                              
Series C Convertible Preferred Stock Per Unit (in shares) 1                              
Over-Allotment Option [Member] | Subsequent Event [Member]                                
Stock Issued During Period, Shares, New Issues (in shares) 1,058,820                              
Over-Allotment Option [Member] | Subsequent Event [Member] | Warrants Issued in Connection with January 2021 Offering [Member]                                
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) 1,058,820