Derivative Income (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative Income.
Closing stock price (in dollars per share)	$ 0.20	$ 0.54
Volatility (as a percent)	85.00%	90.00%
Risk-free rate (as a percent)	1.48%	1.60%
Sentient Loan
Derivative Income.
Derivative income	$ 0.6
Warrant Liability
Derivative Income.
Derivative income		$ 1.7
Level 3
Derivative Income.
Closing stock price (in dollars per share)	$ 0.20	$ 0.54
Volatility (as a percent)	85.00%	90.00%
Risk-free rate (as a percent)	1.48%	1.60%