Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023	Dec. 31, 2019
Number of Options
Balance, beginning of period (in shares)	40,527,848
Options granted (in shares)	0
Options exercised (in shares)	(3,258,748)
Options forfeited (in shares)	(1,904,614)
Balance, end of period (in shares)	35,364,486	40,527,848
Exercisable and vested at end of period (in shares)	32,751,775
Weighted Average Exercise Price
Balance, beginning of period (in dollars per share)	$ 5.60
Options granted (in dollars per share)	0
Options exercised (in dollars per share)	1.83
Options forfeited (in dollars per share)	6.62
Balance, end of period (in dollars per share)	5.89	$ 5.60
Exercisable and vested at end of period (in dollars per shares)	$ 5.64
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Balance, weighted-average remaining contractual life (in years)	4 years 7 months 6 days	5 years 1 month 6 days
Exercisable at end of period, weighted-average remaining contractual life (in years)	4 years 6 months
Balance, aggregate intrinsic value	$ 38.8	$ 20.2
Exercisable and vested at end of period, aggregate intrinsic value	$ 38.3
Closing stock price (in dollars per share)	$ 6,110,000	$ 3,760,000
Outside of 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options early exercised (in shares)			1,100,000