Fair Value Measurements - Valuation Technique (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Minimum
Valuation technique for assets measured and recorded at fair value
Risk-free interest rate (as a percent)	0.50%	0.21%
Volatility (as a percent)	79.82%	119.16%
Expected average term	5 months 1 day	1 year 5 months 1 day
Maximum
Valuation technique for assets measured and recorded at fair value
Risk-free interest rate (as a percent)	1.28%	1.35%
Volatility (as a percent)	128.35%	136.62%
Expected average term	3 years 15 days	4 years 15 days