Fair Value Measurements - Valuation Technique (Details)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Minimum
Valuation technique for assets measured and recorded at fair value
Risk-free interest rate (as a percent)	0.30%	0.25%
Volatility (as a percent)	56.47%	107.98%
Expected average term	2 months 1 day	1 year 2 months 1 day
Maximum
Valuation technique for assets measured and recorded at fair value
Risk-free interest rate (as a percent)	1.04%	1.27%
Volatility (as a percent)	108.92%	129.60%
Expected average term	2 years 9 months 15 days	3 years 9 months 18 days