Stockholders' Equity (Details 2) (USD $)	0 Months Ended					1 Months Ended	9 Months Ended
	Apr. 30, 2014	Mar. 11, 2014	Jan. 15, 2014	Sep. 16, 2013	Feb. 20, 2013	Feb. 28, 2013	Sep. 30, 2014
Stockholders' equity
Net proceeds from public offerings			$ 27,970,256	$ 10,559,892	$ 1,948,766	$ 2,313,560	$ 165,722,618
Proceeds from warrants issued							11,773,240
Shares of common stock issued	22,600,000	3,902,440	10,000,000	18,600,000	18,910,000		23,832,038
Reduction in warrant liability							83,444,573
Common stock
Stockholders' equity
Increase in additional paid-in capital							18,102,213
Shares of common stock issued							36,502,440	[1]
Warrant
Stockholders' equity
Increase in additional paid-in capital							$ 83,444,573

[1] As a result of the January, March and April 2014 public offerings discussed further below, the Company received net proceeds of $165,722,618 of which $11,773,240 in value was ascribed to the warrants issued in the January 2014 public offering. The associated warrants have been separately valued and classified as a liability on the accompanying consolidated balance sheet.