Stockholder's Equity (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Stockholders' Equity
Warrants issued (in shares)				1,481,055
Exercise Price (in dollars per share)				$ 14.00
Shares of common stock issued on exercise of warrants	73,422	117,784	17
Warrants outstanding (in shares)	1,094,085