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Equity - Incentive Equity Awards - Additional Information (Detail) - USD ($) $ in Thousands								1 Months Ended	12 Months Ended
	Nov. 01, 2018	May 14, 2018	Mar. 12, 2018	Feb. 01, 2018	Oct. 02, 2017	May 15, 2017	Feb. 01, 2017	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders Equity Note [Line Items]
Stock options, outstanding									19,263,038	24,108,000
Shares issued, exercise of stock options									8,138,305	356,656
Proceeds from exercise of stock options, net of transaction costs									$ 26,402	$ 638	$ 287
Restricted Stock Units (RSUs)
Stockholders Equity Note [Line Items]
Restricted stock units, outstanding									9,633,250
Percentage of outstanding shares on a fully diluted basis									3.00%
Stock units, Granted									2,633,000	4,197,000
Restricted Stock Units (RSUs) | Stock Incentive Plan 2011
Stockholders Equity Note [Line Items]
Stock units, Granted		190,034		1,305,575		91,504	1,575,000
Stock units, Vesting Period		3 years		3 years		3 years	3 years
Restricted Stock Units (RSUs) | Stock Incentive Plan 2011 | Vesting Period
Stockholders Equity Note [Line Items]
Stock units, Granted	90,000		970,000		220,000	2,310,000
Stock units, Vesting Period						3 years
Restricted Stock Units (RSUs) | Stock Incentive Plan 2011 | Vest over a three year period
Stockholders Equity Note [Line Items]
Shares issued, related to the vesting of RSUs									506,679
Treasury shares for settlement of employee tax obligations									183,828
Stock Options
Stockholders Equity Note [Line Items]
Percentage of outstanding shares on a fully diluted basis									5.00%
Stock units, Vesting Period									4 years
Stock Options | Stock Incentive Plan 2011
Stockholders Equity Note [Line Items]
Stock options, Granted		286,536		2,205,075		131,575	2,642,500
Stock units, Vesting Period				4 years			4 years		4 years
Performance-Based RSUs
Stockholders Equity Note [Line Items]
Shares issued, related to the vesting of RSUs								2,499,750
Treasury shares for settlement of employee tax obligations								764,819

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