Annual report pursuant to Section 13 and 15(d)

Fair Value of Each Award Estimated on Date of Grant Using Black-Scholes-Merton Option-Pricing Formula (Detail)

v3.6.0.2
Fair Value of Each Award Estimated on Date of Grant Using Black-Scholes-Merton Option-Pricing Formula (Detail)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Stock Options      
Schedule of Benefit Obligations Weighted Average Assumptions [Line Items]      
Expected volatility, min   64.60% 56.20%
Expected volatility, max   69.40% 63.70%
Dividend yield, min   0.00% 0.00%
Dividend yield, max   0.00% 0.00%
Risk-free interest rate, min   0.87% 0.82%
Risk-free interest rate, max   1.54% 1.63%
Stock Options | Minimum      
Schedule of Benefit Obligations Weighted Average Assumptions [Line Items]      
Expected life   3 years 6 months 3 years 6 months
Stock Options | Maximum      
Schedule of Benefit Obligations Weighted Average Assumptions [Line Items]      
Expected life   4 years 7 months 4 years 7 months
Performance Based Restricted Stock Units (PBRSUs)      
Schedule of Benefit Obligations Weighted Average Assumptions [Line Items]      
Expected volatility, min 66.50% 52.60%  
Expected volatility, max 97.70% 72.30%  
Dividend yield, min 0.00% 0.00%  
Dividend yield, max 0.00% 0.00%  
Risk-free interest rate, min 1.00% 0.02%  
Risk-free interest rate, max 1.31% 1.07%