Fair Value Measurements - Valuation Technique (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Minimum
Valuation technique for assets measured and recorded at fair value
Risk-free interest rate (as a percent)	0.87%	0.50%
Volatility (as a percent)	49.00%	79.82%
Expected average term	1 year 1 month 21 days	5 months 1 day
Maximum
Valuation technique for assets measured and recorded at fair value
Risk-free interest rate (as a percent)	1.96%	1.28%
Volatility (as a percent)	103.41%	128.35%
Expected average term	5 years 5 months 19 days	3 years 15 days