Quarterly report pursuant to Section 13 or 15(d)

Stockholders' deficit - Warrants (Details)

v3.20.2
Stockholders' deficit - Warrants (Details)
$ / shares in Units, $ in Millions
 9 Months Ended
Jun. 24, 2020
USD ($)
director
$ / shares
shares
Dec. 19, 2019
$ / shares
shares
Nov. 04, 2019
USD ($)
$ / shares
shares
Sep. 17, 2019
$ / shares
shares
May 06, 2019
$ / shares
shares
Sep. 30, 2020
USD ($)
shares
Jul. 20, 2020
director
$ / shares
shares
Jun. 23, 2020
$ / shares
Jun. 01, 2020
shares
Mar. 17, 2020
shares
Dec. 31, 2019
USD ($)
Dec. 12, 2018
shares
Warrants [Abstract]                        
Warrants acquired (in shares)         712,823              
Warrants acquired (in dollars per share) | $ / shares         $ 3.90              
Warrants issued (in shares)           6,125,339            
Warrants, exercise price (in dollars per share) | $ / shares $ 4.25             $ 5.00        
Shares issuable upon exercise of warrants (in shares)                 1,041,666      
Number of shares issuable per warrant (in shares)                       0.50
Warrants outstanding, intrinsic value | $           $ 0.3         $ 12.2  
November 2019 Notes                        
Warrants [Abstract]                        
Increase in fair value of warrants (less than) | $     $ 0.1                  
General and administrative expense                        
Warrants [Abstract]                        
Contract termination expense | $           $ 5.7            
General and administrative expense | November 2019 Notes                        
Warrants [Abstract]                        
Increase in fair value of warrants (less than) | $ $ 0.2                      
Warrant                        
Warrants [Abstract]                        
Warrants, exercise price (in dollars per share) | $ / shares $ 1.25                      
Term of warrants 84 months                      
Shares issuable upon exercise of warrants (in shares) 1,000,000                      
Number of shares issuable per warrant (in shares)           2,560,883       1,003,232    
Number of non-employee directors | director 2                      
June 2020 Warrants                        
Warrants [Abstract]                        
Warrants, exercise price (in dollars per share) | $ / shares $ 1.25                      
Term of warrants 84 months                      
Shares issuable upon exercise of warrants (in shares) 1,000,000                      
July 2020 Warrants                        
Warrants [Abstract]                        
Term of warrants 84 months                      
July 2020 Guarantor Warrants                        
Warrants [Abstract]                        
Warrants, exercise price (in dollars per share) | $ / shares             $ 1.05          
Shares issuable upon exercise of warrants (in shares)             300,000          
July 2020 Director Warrants                        
Warrants [Abstract]                        
Warrants, exercise price (in dollars per share) | $ / shares             $ 1.05          
Shares issuable upon exercise of warrants (in shares)             200,000          
Number of non-employee directors | director             2          
Exercise Price $5.00                        
Warrants [Abstract]                        
Warrants issued (in shares)   937,500 11,000                  
Warrants, exercise price (in dollars per share) | $ / shares   $ 5.00 $ 5.00                  
Term of warrants   24 months 24 months                  
Exercise price $1.82                        
Warrants [Abstract]                        
Warrants issued (in shares)   6,500,000                    
Warrants, exercise price (in dollars per share) | $ / shares   $ 1.82                    
Term of warrants   24 months                    
PIPE Transaction                        
Warrants [Abstract]                        
Warrants issued (in shares)         5,744,991              
Warrants, exercise price (in dollars per share) | $ / shares         $ 4.25              
Broker                        
Warrants [Abstract]                        
Warrants, exercise price (in dollars per share) | $ / shares         $ 3.00              
Term of warrants         24 months              
Broker | PIPE Transaction                        
Warrants [Abstract]                        
Warrants issued (in shares)         220,539              
Advisor | Share-based Payment Arrangement, Tranche One                        
Warrants [Abstract]                        
Term of warrants       12 months                
Advisor | Share-based Payment Arrangement, Tranche Three                        
Warrants [Abstract]                        
Term of warrants       18 months                
Advisor | Exercise Price $0.10                        
Warrants [Abstract]                        
Warrants issued (in shares)       2,500,000                
Warrants, exercise price (in dollars per share) | $ / shares       $ 0.10                
Advisor | Exercise Price $0.10 | Share-based Payment Arrangement, Tranche One                        
Warrants [Abstract]                        
Warrants exercisable (in shares)       1,250,000                
Advisor | Exercise Price $0.10 | Share-based Payment Arrangement, Tranche Two                        
Warrants [Abstract]                        
Warrants exercisable (in shares)       1,250,000                
Advisor | Exercise Price $10.00                        
Warrants [Abstract]                        
Warrants issued (in shares)       1,500,000                
Warrants, exercise price (in dollars per share) | $ / shares       $ 10.00                
Advisor | Exercise Price $10.00 | Share-based Payment Arrangement, Tranche Three                        
Warrants [Abstract]                        
Warrants exercisable (in shares)       1,500,000