Quarterly report pursuant to Section 13 or 15(d)

Convertible Preferred Stock and Warrants (Details)

v3.20.2
Convertible Preferred Stock and Warrants (Details)
$ / shares in Units, $ in Millions
 6 Months Ended
Apr. 09, 2019
USD ($)
Agreement
$ / shares
shares
Jun. 30, 2020
USD ($)
$ / shares
shares
Dec. 31, 2019
shares
Nov. 30, 2019
shares
Jun. 30, 2019
shares
Class Of Stock [Line Items]          
Number of underwriting agreements | Agreement 2        
Warrants to purchase common stock   2,118,094     2,118,344
Aggregate gross proceeds from public offerings | $ $ 70.0        
Underwriting discounts and commissions and estimated offering expenses payable | $ $ 5.0        
Preferred stock, shares outstanding   0 0    
Series A Convertible Preferred Stock          
Class Of Stock [Line Items]          
Share price (in dollars per share) | $ / shares   $ 6.57      
Preferred stock, shares outstanding   0   666  
Convertible preferred stock beneficial conversion feature | $   $ 0.6      
Class A Warrants          
Class Of Stock [Line Items]          
Warrants to purchase common stock   2,118,344      
Warrant exercise price of common stock per share | $ / shares   $ 8.625      
Warrants exercisable date   Oct. 10, 2022      
Maximum ownership percentage to total number stock issued and outstanding holder is prohibited from conversion   4.99%      
Notice period for change in owning percentage   61 days      
Warrants outstanding and remain unexercised excluding Oxford warrants   2,118,094      
Change fair value of warrants | $   $ 9.0      
Class A Warrants | Weighted Average Volatility | Weighted Average          
Class Of Stock [Line Items]          
Fair value of weighted average volatility   86.06%      
Class A Warrants | Weighted Average Expected Term | Weighted Average          
Class Of Stock [Line Items]          
Fair value of weighted expected term   3 years 6 months      
Common Stock | Series A Convertible Preferred Stock          
Class Of Stock [Line Items]          
Conversion of series A stock into common stock       666,000  
Public Offering | Common Stock Agreement | Class A Warrants          
Class Of Stock [Line Items]          
Warrants to purchase common stock 1,951,844        
Share price (in dollars per share) | $ / shares $ 7.50 $ 7.50      
Public Offering | Common Stock Agreement | Common Stock          
Class Of Stock [Line Items]          
Shares issued 8,667,333        
Public Offering | Preferred Stock Agreement | Series A Convertible Preferred Stock          
Class Of Stock [Line Items]          
Shares issued 666        
Public Offering | Preferred Stock Agreement | Class A Warrants          
Class Of Stock [Line Items]          
Warrants to purchase common stock 166,500        
Share price (in dollars per share) | $ / shares $ 7,500