Stockholders' Equity (Deficit) (Equity Compensation Plan) (Narrative) (Details) - USD ($)
 1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Jun. 30, 2014
Sep. 30, 2015
Sep. 30, 2014
Sep. 30, 2015
Sep. 30, 2014
Aug. 31, 2012
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2011
Feb. 28, 2014
Dec. 31, 2012
Apr. 30, 2011
Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock-based compensation expense       $ 1,046,086 $ 722,358   $ 1,066,443 $ 571,924          
Outstanding stock options   1,106,895   1,106,895     1,018,590 633,482     590,047    
Granted       277,875     507,879 186,736          
Weighted average grant-date fair value       $ 3.33     $ 5.66 $ 8.51          
Fair value of stock options vested             $ 1,704,121            
Unrecognized stock-based compensation expense   $ 3,114,452   $ 3,114,452     $ 3,872,221            
unrecognized stock-based compensation expense, recognition period       15 months 24 days     14 months 27 days            
Warrants to Purchase Shares of Common Stock Issuable at Price One [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Exercise price of warrants   $ 0.48   $ 0.48                  
Warrant liabilities outstanding   17,392   17,392                  
Warrants to Purchase Shares of Common Stock Issuable at Price Two [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Exercise price of warrants   $ 12.50   $ 12.50                  
Warrant liabilities outstanding   125,000   125,000                  
Common Stock Warrants [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Granted             52,695 125,000 32,610        
Exercise price of warrants           $ 4.83 $ 11.03 $ 12.50 $ 0.48        
Expiration term           10 years   5 years 10 years        
Number of shares of common stock issuable through warrants           20,549       15,218      
Restricted stock awards [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock-based compensation expense             $ 25,534          
Outstanding stock options [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock-based compensation expense   $ 245,289 $ 224,586 $ 942,136 $ 722,358   $ 570,760 $ 131,178          
Non-employees [Member] | Restricted stock awards [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock-based compensation expense   $ 13,950 $ 103,950                
2014 Stock Option Plan [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock Incentive Plan, shares authorized 500,000           500,000            
Expiration term 10 years                        
Outstanding stock options             436,748            
2009 Stock Incentive Plan [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock Incentive Plan, shares authorized             869,565         652,174 217,391
Expiration term             10 years            
Outstanding stock options             581,842 633,482          
2009 and 2014 Plans [Member]                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Outstanding stock options             1,018,590            
Granted             1,416,091            
Forfeited             115,398            
Common shares available for grant             68,872