Quarterly report pursuant to Section 13 or 15(d)

Convertible Preferred Stock and Warrants (Details)

v3.19.2
Convertible Preferred Stock and Warrants (Details)
$ / shares in Units, $ in Millions
6 Months Ended
Apr. 09, 2019
USD ($)
Agreement
$ / shares
shares
Apr. 05, 2019
shares
Jun. 30, 2019
USD ($)
$ / shares
shares
Dec. 31, 2018
$ / shares
Class Of Stock [Line Items]        
Number of underwriting agreements | Agreement 2      
Aggregate gross proceeds from public offerings | $ $ 70.0      
Underwriting discounts and commissions and estimated offering expenses payable | $ $ 5.0      
Preferred stock, par value (in dollars per share) | $ / shares     $ 0.001 $ 0.001
Series A Convertible Preferred Stock        
Class Of Stock [Line Items]        
Share price (in dollars per share) | $ / shares     $ 6.57  
Minimum ownership percentage to total number stock Issued and outstanding holder is prohibited from conversion 9.99%      
Notice period for change in owning percentage 61 days      
Convertible preferred stock beneficial conversion feature | $     $ 0.6  
Preferred stock, par value (in dollars per share) | $ / shares $ 0.001      
Class A Warrants        
Class Of Stock [Line Items]        
Warrants to purchase common stock | shares     2,118,344  
Notice period for change in owning percentage     61 days  
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%  
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 | shares 1,000 1,000    
Minimum ownership percentage to total number stock Issued and outstanding holder is prohibited from conversion   9.99%    
Notice period for change in owning percentage   61 days    
Public Offering | Common Stock Agreement | Class A Warrants        
Class Of Stock [Line Items]        
Warrants to purchase common stock | shares 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 | shares 8,667,333      
Public Offering | Preferred Stock Agreement | Series A Convertible Preferred Stock        
Class Of Stock [Line Items]        
Shares issued | shares 666      
Public Offering | Preferred Stock Agreement | Class A Warrants        
Class Of Stock [Line Items]        
Warrants to purchase common stock | shares 166,500      
Share price (in dollars per share) | $ / shares $ 7,500