Warrants (Details) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Class of Warrant or Right [Line Items]
Number of warrants outstanding	11,396,262
Warrants exercised via cashless exercises	0	0
Class of Warrants Issued January 11, 2017
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)	$ 0.001
Number of warrants outstanding	7,258,263
November 21, 2012 Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)	$ 0.00
Number of warrants outstanding	4,137,999