Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Summary of stock option activity (Details)

v3.20.1
Stock-Based Compensation - Summary of stock option activity (Details) - Stock Option [Member] - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options, Beginning Balance 2,502,012 938,932  
Options, Granted 0 1,725,000  
Options, Exercised 0 0  
Options, Expired 0 (94,738)  
Options, Forfeited 0 (67,232)  
Options, Ending Balance 2,502,012 2,502,012 938,932
Options, Exercisable 493,696    
Weighted Average Exercise Price, Beginning Balance $ 3.62 $ 15.18  
Weighted Average Exercise Price, Granted 0.00 0.42  
Weighted Average Exercise Price, Exercised 0.00 0.00  
Weighted Average Exercise Price, Expired 0.00 58.25  
Weighted Average Exercise Price, Forfeited 0.00 5.95  
Weighted Average Exercise Price, Ending Balance 3.62 $ 3.62 $ 15.18
Weighted Average Exercise Price, Exercisable $ 16.17    
Weighted Average Remaining Contractual Life, Balance Outstanding 6 years 3 months 4 days 6 years 6 months 4 days 6 years 2 months 9 days
Weighted Average Remaining Contractual Life, Exercisable 5 years 3 months 15 days    
Aggregate Intrinsic Value, Ending Balance $ 0 $ 153,353 $ 0
Aggregate Intrinsic Value, Exercisable 0    
Grant date fair value of options granted $ 0 $ 470,000  
Weighted average grant date fair value $ 0.00 $ 0.27