Annual report pursuant to Section 13 and 15(d)

Stock Options, Warrants and Restricted Common Stock (Other Common Stock Purchase Warrants) (Narrative) (Details)

v3.21.1
Stock Options, Warrants and Restricted Common Stock (Other Common Stock Purchase Warrants) (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of warrants issued 1,492,487    
Number of warrants exercised 1,492,487    
Proceeds from common stock warrants $ 2.9    
Warrant [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Warrants to purchase common stock 1,908,144    
Exercise price $ 1.94    
Number of warrants issued 1,257,235    
Number of warrants exercised 543,686    
Nonqualified [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Awards outstanding 2,061,770 3,574,257 1,671,113