Annual report pursuant to Section 13 and 15(d)

Assumptions Used within Option-Pricing Model (Detail)

v2.4.0.8
Assumptions Used within Option-Pricing Model (Detail) (Options)
12 Months Ended
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Dividend yield 0.00%
Expected stock price volatility, minimum 50.40%
Expected stock price volatility, maximum 54.80%
Risk-free interest rate, minimum 0.80%
Risk-free interest rate, maximum 1.82%
Minimum
 
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected unit life 5 years
Maximum
 
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Expected unit life 6 years 3 months