Equity - Warrants (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended			12 Months Ended
	Sep. 19, 2017	May 31, 2016	Sep. 30, 2014	Sep. 30, 2012	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Oct. 31, 2015
Weighted Average Exercise Price Per Share
Warrant liability							$ 1.5
Warrant
Number of Underlying Shares
Outstanding, beginning balance (in shares)					11,478,172	17,578,950
Dilution adjustment (in shares)					39,524	157,302
Expired (in shares)						(6,258,080)
Outstanding, end balance (in shares)					11,517,696	11,478,172
Weighted Average Exercise Price Per Share
Outstanding, beginning balance (in dollars per share)					$ 0.81	$ 2.17
Dilution adjustment (in dollars per share)					0.87
Expired during period						4.62
Outstanding, end balance (in dollars per share)					$ 0.81	$ 0.81
2012 Warrants
Number of Underlying Shares
Outstanding, beginning balance (in shares)	3,431,649
Dilution adjustment (in shares)	2,826,431
Outstanding, end balance (in shares)	6,258,080
Weighted Average Exercise Price Per Share
Outstanding, beginning balance (in dollars per share)	$ 8.42
Outstanding, end balance (in dollars per share)	$ 4.62
Term of warrants				5 years
2014 Warrants
Number of Underlying Shares
Outstanding, beginning balance (in shares)	4,746,000
Dilution adjustment (in shares)	771,696
Outstanding, end balance (in shares)	5,517,696
Weighted Average Exercise Price Per Share
Outstanding, beginning balance (in dollars per share)	$ 1.21
Outstanding, end balance (in dollars per share)	$ 0.85
Sentient
Weighted Average Exercise Price Per Share
Principal amount of loan								$ 5.0
Sentient | 2012 Warrants
Number of Underlying Shares
Outstanding, beginning balance (in shares)	3,431,649
Sentient | 2014 Warrants
Number of Underlying Shares
Outstanding, beginning balance (in shares)	4,746,000
Weighted Average Exercise Price Per Share
Term of warrants			5 years
Registered Offering
Weighted Average Exercise Price Per Share
Sale price (in dollars per shares)		$ 0.50
Common stock issued (in shares)		8,000,000
Gross proceeds from common stock sale		$ 4.0
Registered Offering | 2016 Warrants
Number of Underlying Shares
Outstanding, end balance (in shares)		6,000,000
Weighted Average Exercise Price Per Share
Number of shares of common stock per capital unit (in shares)		0.75
Term of warrants		5 years
Number of common shares which can be purchased with each warrant		0.75