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Stock Incentive Plans - Schedule for the Estimated Fair Value at Date of Option Grand Using Black Scholes Option Pricing Model (Detail) - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Weighted average fair value per share of option $ 1.40 $ 5.04 $ 8.49
Expected term 5 years 6 months 5 years 3 months 18 days 5 years 3 months 18 days
Risk free interest rate 1.41% 1.66% 0.76%
Risk free interest rate 1.70% 1.83% 1.42%
Volatility 65.00% 77.00% 77.00%
Dividend yield 0.00% 0.00% 0.00%
Forfeiture rate 18.56% 25.56% 19.18%