Warrants (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Class of Warrant or Right [Line Items]
Warrants exercised via cashless exercises	844,760	419,244	1,037,330
Warrants exercised for cash		313,756
Cash proceeds generated from exercise of warrants		$ 2.1
Shares of common stock issued from exercise of warrants	660,680	603,545.000	809,498
November 21, 2012 Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)		$ 7.86
Number of warrants outstanding		695,383