Stockholders' Equity (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Stockholders Equity [Line Items]
Share-based compensation expense	$ 805,232	$ 656,947	$ 2,121,049	$ 3,638,972
Research and development expenses [Member]
Stockholders Equity [Line Items]
Share-based compensation expense	385,153	245,000	957,907	723,558
General and administrative expenses [Member]
Stockholders Equity [Line Items]
Share-based compensation expense	$ 420,079	$ 411,947	$ 1,163,142	$ 2,915,414