Summary of Significant Accounting Policies (Schedule of Share-based Compensation Expense) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 199,627	$ 528,878
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	60,735	189,917
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	192,633	338,961
Restructuring benefit [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ (53,741)