Stock-Based Compensation - Summary of Stock-based Compensation Expenses for Stock Options and Unvested Common Stock (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 100,258	$ 22,127	$ 134,424	$ 45,786
Cost of Sales [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	1,815	1,055	2,878	2,060
Research and Development Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	76,234	11,567	93,626	23,933
Selling and Marketing Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	5,572	2,453	9,928	5,228
General and Administrative Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	15,547	5,904	25,989	11,819
Stock-based Compensation, Net Of Amounts Capitalized [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	99,168	20,979	132,421	43,040
Capitalized Stock Based Compensation - Property And Equipment Net And Intangible Assets Net [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation expense	$ 1,090	$ 1,148	$ 2,003	$ 2,746