Quarterly report pursuant to Section 13 or 15(d)

Equity - Narrative (Details)

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Equity - Narrative (Details)
1 Months Ended 2 Months Ended 3 Months Ended 12 Months Ended
Feb. 16, 2018
USD ($)
$ / shares
shares
Sep. 15, 2017
USD ($)
Jul. 29, 2017
warrant
$ / shares
shares
Apr. 30, 2018
$ / shares
shares
Jan. 31, 2018
$ / shares
shares
Aug. 31, 2017
$ / shares
Jul. 31, 2017
$ / shares
Jan. 31, 2017
USD ($)
$ / shares
shares
Aug. 31, 2017
shares
Mar. 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
shares
May 09, 2018
$ / shares
shares
Apr. 06, 2018
shares
May 02, 2016
shares
Apr. 22, 2016
shares
Class of Stock [Line Items]                              
Shares authorized                           80,000,000  
Preferred stock authorized (in shares)                   5,000,000 5,000,000     5,000,000  
Common stock authorized (in shares)                   75,000,000 75,000,000     75,000,000  
Preferred stock, shares issued                   0 0        
Additional shares available for purchase                   230,000          
Exercise price (in dollars per share) | $ / shares                   $ 1.76          
Shares granted, contractual term                   9 years 3 months 7 days 9 years 26 days        
Options granted, aggregate fair value | $                   $ 300,000          
Unrecognized compensation cost, net of estimated forfeitures, related to the Company's non-vested equity awards | $                   $ 2,500,000          
Weighted average period of expected recognition of compensation cost (in years)                   3 years 12 days          
Options exercised (in shares)                   0          
Exercise price per warrant (in dollars per share) | $ / shares $ 2.80                 $ 2.80          
Warrant term 5 years                            
Proceeds from issuance or sale of equity | $ $ 9,000,000                            
Net proceeds from registered offering | $ $ 8,200,000                            
Warrants, initial exercise period 6 months                            
Sale of stock, right of first refusal, period 9 months                            
Sale of stock, cash and warrant compensation tail fee, period 6 months                            
Securities Purchase Agreement                              
Class of Stock [Line Items]                              
Class of warrants, aggregate amounts (in shares) 2,273,700                            
Proceeds from issuance or sale of equity | $ $ 9,000,000                            
Placement Agency Agreement                              
Class of Stock [Line Items]                              
Commissions paid, percentage of gross proceeds 6.50%                            
Sale of stock, warrants to be issued, percentage of common stock sold in transactions 3.00%                            
Sale of stock, reimbursement of expenses | $ $ 75,000                            
2015 Stock Plan                              
Class of Stock [Line Items]                              
Total number of underlying shares of common stock available under 2015 Stock Plan                             2,500,000
Science Advisory Board Member                              
Class of Stock [Line Items]                              
Additional shares available for purchase         10,000                    
Exercise price (in dollars per share) | $ / shares         $ 1.89                    
Shares granted, contractual term         10 years                    
Science Advisory Board Member | Employee Stock Option                              
Class of Stock [Line Items]                              
Vesting period         4 years                    
Science Advisory Board                              
Class of Stock [Line Items]                              
Additional shares available for purchase               20,000              
Exercise price (in dollars per share) | $ / shares               $ 2.31              
Vesting period               4 years              
Term of awards               10 years              
Aggregate fair value of options granted | $               $ 35,196              
Board and Management                              
Class of Stock [Line Items]                              
Additional shares available for purchase                 140,000            
Exercise price (in dollars per share) | $ / shares           $ 2.88 $ 1.87                
Vesting period                 4 years            
Term of awards                 10 years            
Aggregate fair value of options granted | $                   $ 269,592          
The Warrants                              
Class of Stock [Line Items]                              
Period of agreement     12 months                        
Number of warrants issued | warrant     2                        
Vesting period     12 months                        
Expiration period     5 years                        
Stock compensation expense | $                   $ 63,000          
GSK Consulting Agreement Warrant One                              
Class of Stock [Line Items]                              
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 [Line Items]                              
Class of warrants, aggregate amounts (in shares)     50,000                        
Exercise price per warrant (in dollars per share) | $ / shares     $ 3.00                        
Agents | At Market Issuance Sales Agreement                              
Class of Stock [Line Items]                              
Commissions paid, percentage of gross proceeds   3.00%                          
Common Stock                              
Class of Stock [Line Items]                              
Class of warrants, aggregate amounts (in shares) 2,145,000                            
Common Stock | Securities Purchase Agreement                              
Class of Stock [Line Items]                              
Class of warrants, aggregate amounts (in shares) 2,145,000                            
Number of shares sold 4,290,000                            
Sale of common stock (in dollars per share) | $ / shares $ 2.10                            
Common Stock | Agents | At Market Issuance Sales Agreement | Maximum                              
Class of Stock [Line Items]                              
Aggregate sales price | $   $ 13,000,000                          
Subsequent Event                              
Class of Stock [Line Items]                              
Class of warrants, aggregate amounts (in shares)                       100,000      
Exercise price per warrant (in dollars per share) | $ / shares                       $ 3.00      
Subsequent Event | 2015 Stock Plan                              
Class of Stock [Line Items]                              
Total number of underlying shares of common stock available under 2015 Stock Plan                         4,500,000    
Subsequent Event | Consulting Agreement Warrant Three                              
Class of Stock [Line Items]                              
Class of warrants, aggregate amounts (in shares)       100,000                      
Exercise price per warrant (in dollars per share) | $ / shares       $ 3.00                      
Warrant term       3 years