Quarterly report pursuant to Section 13 or 15(d)

Equity - Narrative (Details)

v3.19.2
Equity - Narrative (Details)
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Jul. 23, 2019
USD ($)
$ / shares
Jul. 08, 2019
shares
Oct. 04, 2018
USD ($)
shares
Jul. 29, 2017
technology
$ / shares
shares
Apr. 30, 2019
USD ($)
$ / shares
shares
Mar. 31, 2019
USD ($)
$ / shares
shares
Jun. 30, 2018
USD ($)
$ / shares
shares
Apr. 30, 2018
$ / shares
shares
Feb. 28, 2018
USD ($)
$ / shares
shares
Sep. 30, 2017
USD ($)
Jun. 30, 2019
USD ($)
$ / shares
shares
Mar. 31, 2019
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
$ / shares
shares
Jun. 30, 2018
USD ($)
$ / shares
shares
Mar. 31, 2018
USD ($)
shares
Jun. 30, 2019
USD ($)
$ / shares
shares
Jun. 30, 2018
USD ($)
$ / shares
shares
Dec. 31, 2018
$ / shares
shares
Aug. 08, 2019
$ / shares
Mar. 29, 2019
$ / shares
Class of Stock                                        
Shares authorized (in shares)                     105,000,000         105,000,000        
Preferred stock authorized (in shares)                     5,000,000   5,000,000     5,000,000   5,000,000    
Common stock authorized (in shares)                     100,000,000   75,000,000     100,000,000   75,000,000    
Preferred stock, shares issued (in shares)                     0   0     0   0    
Maximum amount of shares to be sold in transaction | $     $ 20,000,000.0                                  
Shares of common stock issued | $                             $ 5,122,000          
Common stock, par value (in dollars per share) | $ / shares                     $ 0.001   $ 0.001     $ 0.001   $ 0.001    
Options exercised (in shares)                               25,000        
Weighted average exercise price, granted (in dollars per share) | $ / shares                               $ 0.20        
Proceeds from exercise of stock options | $                               $ 5,000 $ 0      
Shares granted (in shares)                               45,000        
Shares granted, aggregate fair value | $                     $ 40,000.00         $ 40,000.00        
Exercise price (in dollars per share) | $ / shares                               $ 1.15        
Shares granted, contractual term                               8 years 5 months 1 day   9 years 5 months 4 days    
Unrecognized compensation cost, net of estimated forfeitures, related to the Company's non-vested equity awards | $                     $ 2,600,000         $ 2,600,000        
Weighted average period of expected recognition of compensation cost (in years)                               2 years 3 months 10 days        
Period of agreement       12 months                                
Proceeds from issuance or sale of equity | $             $ 2,300,000                          
Former Employee                                        
Class of Stock                                        
Options exercised (in shares)           25,000                            
Weighted average exercise price, granted (in dollars per share) | $ / shares           $ 0.20                            
Proceeds from exercise of stock options | $           $ 5,000                            
2015 Stock Plan                                        
Class of Stock                                        
Total number of underlying shares of common stock available under 2015 Stock Plan                     4,500,000         4,500,000        
Common Stock                                        
Class of Stock                                        
Shares of common stock issued (in shares)                             4,290,000          
Shares of common stock issued | $                             $ 5,000          
Options exercised (in shares)                       25,000                
The Warrants                                        
Class of Stock                                        
Number of warrants issued | technology       2                                
Vesting period       12 months                                
Expiration period       5 years                                
Stock compensation expense | $                     $ 0.00     $ 40,000.00   $ 2,000.000 $ 100,000      
Consulting fees | $                               $ 20,000        
The Warrants | Subsequent Event                                        
Class of Stock                                        
Class of warrants, aggregate amounts (in shares)   150,000                                    
Exercise price per warrant (in dollars per share) | $ / shares                                     $ 1.64  
Warrant term   3 years                                    
GSK Consulting Agreement Warrant One                                        
Class of Stock                                        
Class of warrants, aggregate amounts (in shares)       100,000                                
Exercise price per warrant (in dollars per share) | $ / shares       $ 2.41                                
GSK Consulting Agreement Warrant Two                                        
Class of Stock                                        
Class of warrants, aggregate amounts (in shares)       50,000                                
Exercise price per warrant (in dollars per share) | $ / shares       $ 3.00                                
Consulting Agreement Warrant Three                                        
Class of Stock                                        
Class of warrants, aggregate amounts (in shares)               100,000                        
Exercise price per warrant (in dollars per share) | $ / shares               $ 3.00                        
Warrant term               3 years                        
Lincoln Park                                        
Class of Stock                                        
Shares of common stock issued (in shares)     243,013               0 605,367 1,399,153              
Shares of common stock issued | $                       $ 883,000                
Lincoln Park | Common Stock                                        
Class of Stock                                        
Shares of common stock issued (in shares)                       605,367                
Lincoln Park | Commitment Shares                                        
Class of Stock                                        
Maximum amount of shares to be sold in transaction | $     $ 20,000,000.0                                  
Shares of common stock issued (in shares)     121,507               0 5,367 10,918              
Shares of common stock issued | $     $ 337,788                 $ 900,000 $ 1,800,000              
At Market Issuance Sales Agreement                                        
Class of Stock                                        
Commissions paid, percentage of gross proceeds (percent)                   3.00%                    
At Market Issuance Sales Agreement | Roth Capital Partners and National Securities Corporation | Maximum | Common Stock                                        
Class of Stock                                        
Aggregate sales price | $                   $ 13,000,000                    
At Market Issuance Sales Agreement | Oppenheimer & Co. Inc. | Common Stock | Subsequent Event                                        
Class of Stock                                        
Aggregate sales price | $ $ 15,000,000                                      
Commissions paid, percentage of gross proceeds (percent) 3.00%                                      
Common stock, par value (in dollars per share) | $ / shares $ 0.001                                      
Securities Purchase Agreement                                        
Class of Stock                                        
Exercise price per warrant (in dollars per share) | $ / shares                 $ 2.80                      
Warrant term                 5 years                      
Number of units sold (in shares)                 4,290,000                      
Proceeds from issuance or sale of equity | $                 $ 9,000,000.0                      
Net proceeds from registered offering | $                 $ 8,200,000                      
Warrants, initial exercise period                 6 months                      
Securities Purchase Agreement | Common Stock                                        
Class of Stock                                        
Class of warrants, aggregate amounts (in shares)                 2,145,000                      
Sale of common stock (in dollars per share) | $ / shares                 $ 2.10                      
June 2018 Registered Direct Offering                                        
Class of Stock                                        
Exercise price per warrant (in dollars per share) | $ / shares             $ 2.02             $ 2.02     $ 2.02      
Expiration period             5 years                          
Number of units sold (in shares)             1,092,636                          
Sale of common stock (in dollars per share) | $ / shares             $ 2.105             $ 2.105     $ 2.105      
Warrants, initial exercise period             6 months                          
Common stock offered for each warrant (in shares)             0.65             0.65     0.65      
March 2019 Registered Direct Offerings                                        
Class of Stock                                        
Exercise price per warrant (in dollars per share) | $ / shares           $ 1.10           $ 1.10                
Warrant term           5 years                            
Net proceeds from registered offering | $           $ 4,700,000                            
Units sold in period (in units)           5,250,000                            
Common stock offered for each warrant (in shares)           0.5           0.5                
Unit offering (in dollars per unit) | $ / shares           $ 1.00           $ 1.00                
March 2019 Registered Direct Offerings | Common Stock                                        
Class of Stock                                        
Exercise price per warrant (in dollars per share) | $ / shares                                       $ 1.10
Number of units sold (in shares)           1                            
March 2019 Registered Direct Offerings | Underwriter                                        
Class of Stock                                        
Unit offering (in dollars per unit) | $ / shares           $ 0.93           $ 0.93                
April Offerings                                        
Class of Stock                                        
Shares of common stock issued | $                     $ 3,584,000                  
Exercise price per warrant (in dollars per share) | $ / shares         $ 1.75                              
Warrant term         5 years                              
Number of units sold (in shares)         9,375,000                              
Net proceeds from registered offering | $         $ 14,000,000.0                              
Common stock offered for each warrant (in shares)         0.5                              
Unit offering (in dollars per unit) | $ / shares         $ 1.60                              
April Offerings | Common Stock                                        
Class of Stock                                        
Shares of common stock issued (in shares)                     9,375,000                  
Shares of common stock issued | $                     $ 9,000                  
Number of units sold (in shares)         1