Summary of Significant Accounting Policies (Schedule of Share-based Compensation Expense) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 133,604	$ 363,105	$ 333,231	$ 891,983
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	12,490	87,304	73,225	277,221
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 121,114	$ 275,801	313,747	$ 614,762
Restructuring benefit [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense			$ (53,741)