Equity and Stock-based Compensation - Summary of Stock Option Activity (Detail)	6 Months Ended
	Jun. 30, 2016 shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding Opening	30,278,364
Granted	1,440,300
Cancelled/forfeited	(912,816)
Exercised	(3,171,668)
Number of Shares, Outstanding Closing	27,634,180