Stockholders' Equity (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Proceeds from sales of common stock, net of expenses	$ 0	$ 21,445,785
Exercised warrants (in shares)	50,000
Common Stock
Shares of common stock issued	45,000
Common Stock | Option exercise price, weighted average of $3.31 per share
Exercise price of stock options exercised (in USD per share)	$ 2.97