Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation and Warrants (Details Textual)

v3.10.0.1
Stock-Based Compensation and Warrants (Details Textual) - USD ($)
1 Months Ended 12 Months Ended
Oct. 10, 2018
Oct. 10, 2014
Nov. 18, 2016
Mar. 20, 2007
Dec. 31, 2018
Dec. 31, 2017
Oct. 31, 2018
Oct. 15, 2018
Sep. 24, 2018
Dec. 26, 2017
Sep. 07, 2017
Aug. 25, 2016
May 15, 2015
Oct. 22, 2013
Nov. 02, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options         $ 824,000                    
Sale of Stock, Number of Shares Issued in Transaction         3,500,000                    
Change in fair value of warrant liabilities         $ (4,083,000) $ (10,738,000)                  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights 13,672,173                            
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 1.38           $ 1.38                
Warrants Not Settleable in Cash, Fair Value Disclosure                   $ 9,000          
Proceeds from Stock Options Exercised         $ 0 $ 166,000                  
Common Stock, Par or Stated Value Per Share 0.001       $ 0.001 $ 0.001                  
Share Price   $ 61.25     $ 0.56 $ 17.85                  
Temporary Equity, Par or Stated Value Per Share $ 1,000                            
Class of Warrant or Right, Outstanding 13,672,173                            
IPO [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Sale of Stock, Price Per Share     $ 35.00                        
Change in fair value of warrant liabilities         $ 3,700,000 $ 9,000,000                  
Stock Issued During Period, Shares, New Issues     714,286                        
Class of Warrant or Right, Number of Securities Called by Warrants or Rights     1,428,571                        
Warrants Not Settleable in Cash, Fair Value Disclosure     $ 15,700,000   100,000,000 $ 3,700,000                  
IPO [Member] | Series A [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Sale of Stock, Number of Shares Issued in Transaction 2,520,000                            
Share Price $ 1.15                            
IPO [Member] | Series B [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Sale of Stock, Number of Shares Issued in Transaction 15,723                            
Share Price $ 1,000                            
Over-Allotment Option [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Stock Issued During Period, Shares, New Issues 2,428,825                            
Class of Warrant or Right, Number of Securities Called by Warrants or Rights 2,428,825                            
Issue of warrants to purchase common stock 1,807,826                            
Series A Warrants [Member] | IPO [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Class of Warrant or Right, Exercise Price of Warrants or Rights     $ 50.05                        
Series B Warrants [Member] | IPO [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Class of Warrant or Right, Exercise Price of Warrants or Rights     $ 60.20                        
Warrant [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Change in fair value of warrant liabilities         $ 416,000                    
Class of Warrant or Right, Number of Securities Called by Warrants or Rights               13,672,173              
Share Based Compensation Arrangement By Share Based Payment Award Non Option Equity Instruments Warrants Exercisable Number                   714          
Employees And Directors [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross         671,500 90,262                  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Fair Value         $ 300,000 $ 1,800,000                  
Employee [Member] | General and Administrative Expenses and Research and Development Expense [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Allocated Share-based Compensation Expense         1,800,000 3,000,000                  
Consultant [Member] | General and Administrative Expenses and Research and Development Expense [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Allocated Share-based Compensation Expense         $ 297,000 434,000                  
2007 Stock Plan [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number       71,429 18,645                    
2007 Stock Plan [Member] | Maximum [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross       7,143                      
2010 Stock Plan [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number         920,337                   85,714
2010 Stock Plan [Member] | Maximum [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Common Stock, Capital Shares Reserved for Future Issuance                 1,000,000   500,000 400,000 228,572 171,429  
2010 Stock Plan [Member] | Minimum [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Common Stock, Capital Shares Reserved for Future Issuance                 500,000   400,000 228,572 171,429 85,714  
Stock Warrants [Member]                              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                              
Share-based Compensation Arrangement by Share-based Payment Award, Warrants, Exercisable Number   200,852                          
Share-based Compensation Arrangement by Share-based Payment Award, Warrants, Vested and Expected to Vest Outstanding, Number   61.25                          
Sale of Stock, Number of Shares Issued in Transaction   14,059,616                          
Sale of Stock, Price Per Share   $ 1.47                          
Proceeds from Issuance of Common Stock   $ 19,100,000                          
Change in fair value of warrant liabilities   $ 7,400,000       1,700,000                  
Warrants Not Settleable in Cash, Fair Value Disclosure         $ 0 $ 416,000                  
Issue of warrants to purchase common stock   0.50