Stock-Based Compensation - Summary of Stock-based Compensation Expenses for Stock Options and Unvested Common Stock (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation, net of amounts capitalized	$ 146,906	$ 72,945	$ 417,268	$ 205,366
Capitalized stock-based compensation-Property and equipment, net and Intangible assets, net	1,716	1,678	7,146	3,681
Stock-based compensation expense	148,622	74,623	424,414	209,047
Location, Statement of Income, Balance [Axis]: us-gaap:CostOfGoodsAndServiceExcludingDepreciationDepletionAndAmortization
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	14,177	4,247	46,289	7,125
Location, Statement of Income, Balance [Axis]: us-gaap:GeneralAndAdministrativeExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	64,254	30,372	155,643	56,361
Location, Statement of Income, Balance [Axis]: us-gaap:ResearchAndDevelopmentExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	44,853	31,766	161,172	125,392
Location, Statement of Income, Balance [Axis]: us-gaap:SellingAndMarketingExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 23,622	$ 6,560	$ 54,164	$ 16,488