Stockholders' Equity (Deficit) - Assumptions Related to Share-based Compensation (Details) - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Grants in period, weighted average grant date fair value $ 8.95 $ 14.74 $ 3.02
Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Volatility 53.00% 60.00%  
Expected life (in years) 6 years 2 months 1 day    
Risk-free interest rate, minimum 1.38% 1.53% 0.70%
Risk-free interest rate, maximum 1.91% 2.05% 1.80%
Dividend yield 0.00% 0.00% 0.00%
Minimum [Member] | Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Volatility     58.00%
Expected life (in years)   5 years 5 years
Maximum [Member] | Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Volatility     60.00%
Expected life (in years)   6 years 3 months 18 days 7 years 2 months 12 days