v2.4.0.8
Share-Based Compensation - Summary of Stock Options Activity (Detail) (USD $)
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]    
Options Outstanding, Beginning Balance 4,165,835  
Granted 1,344,714  
Exercised (121,556)  
Forfeited (153,133)  
Expired (72,616)  
Options Outstanding, Ending Balance 5,163,244 4,165,835
Options Exercisable, Ending Balance 2,745,494  
Options vested and expected to vest, Ending Balance 5,033,649  
Weighted Average Exercise Price Per Share, Outstanding Beginning Balance $ 12.05  
Weighted Average Exercise Price Per Share, Granted $ 19.01  
Weighted Average Exercise Price Per Share, Exercised $ 10.74  
Weighted Average Exercise Price Per Share, Forfeited $ 12.31  
Weighted Average Exercise Price Per Share, Expired $ 11.24  
Weighted Average Exercise Price Per Share, Outstanding Ending Balance $ 13.89 $ 12.05
Weighted Average Exercise Price Per Share, Exercisable Ending Balance $ 11.08  
Weighted Average Exercise Price Per Share, Vested and expected to vest, Ending Balance $ 13.77  
Weighted Average Remaining Contractual Life, Outstanding 7 years 6 months 8 years 11 days
Weighted Average Remaining Contractual Life, Exercisable Ending Balance 6 years 7 months 13 days  
Weighted Average Remaining Contractual Life, Vested and Expected to Vest, Ending Balance 7 years 5 months 16 days  
Aggregate Intrinsic Value, Outstanding Beginning Balance $ 23,519  
Aggregate Intrinsic Value, Outstanding Ending Balance 56,502 23,519
Aggregate Intrinsic Value, Exercisable Ending Balance 37,724  
Aggregate Intrinsic Value, Vested and Expected to Vest, Ending Balance $ 55,682