Stock Based Compensation-Schedule of Estimated Fair Value of Employee Stock Options Using Black-Scholes Valuation Model (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	62.90%	66.40%	70.80%
Expected volatility, maximum	68.90%	71.20%	71.70%
Risk-free interest rate, minimum	1.40%	1.60%	0.90%
Risk-free interest rate, maximum	1.90%	2.00%	1.90%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 2 months 12 days	5 years 3 months 18 days	5 years 6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	7 years 2 months 12 days	6 years 1 month 6 days	6 years 1 month 6 days