v3.19.3
Note 9 - Redeemable Convertible Preferred Stock (Details Textual) - shares
1 Months Ended
May 31, 2019
Sep. 30, 2019
Dec. 31, 2018
Dec. 31, 2017
Debt Conversion, Converted Instrument, Shares Issued 367,041      
Preferred Stock, Shares Issued, Total   0 0  
Preferred Stock, Shares Authorized   1,000,000 1,000,000  
Preferred Stock, Shares Outstanding, Ending Balance   0 0  
Conversion of Notes into Series B Convertible Preferred Stock [Member]        
Debt Conversion, Converted Instrument, Shares Issued 367,041      
Series A Redeemable Convertible Preferred Stock Without Giving Effect To The Reverse Stock Split [Member]        
Redeemable convertible preferred stock, shares issued (in shares)   0 2,034,548 56,672,658
Redeemable convertible preferred stock, shares outstanding (in shares)   0 2,034,548 56,672,658
Series B Redeemable Convertible Preferred Stock Without Giving Effect To The Reverse Stock Split [Member]        
Redeemable convertible preferred stock, shares issued (in shares)   0 1,833,387 51,069,262
Redeemable convertible preferred stock, shares outstanding (in shares)   0 1,833,387 51,069,262