Warrants (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jan. 31, 2017
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)					$ 0.001
Warrants exercised via cashless exercises	0	0	0	419,244
Warrants exercised for cash				313,756
Cash proceeds generated from exercise of warrants	$ 2.1			$ 2.1
Shares of common stock issued from exercise of warrants	267,966			603,545.000
Class of Warrants Issued January 11, 2017
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)	$ 0.001		$ 0.001
Number of warrants outstanding	7,258,263		7,258,263
November 21, 2012 Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)	$ 7.86		$ 7.86
Number of warrants outstanding	695,383		695,383