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Stock-Based Compensation - Summary of Fair Value of Stock Options for Employees was Estimated using Black-Scholes Option Pricing Model (Details)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Assumed risk-free interest rate   1.57%  
Assumed volatility   61.53% 71.09%
Expected option life 6 years 1 month 6 days 6 years 1 month 6 days 6 years 1 month 6 days
Expected dividend yield 0.00% 0.00% 0.00%
Minimum      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Assumed risk-free interest rate 1.40%   1.82%
Assumed volatility 52.91%    
Maximum      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Assumed risk-free interest rate 1.53%   2.09%
Assumed volatility 53.49%