Investments and Fair Value Measurements - Summary Of Assets And Liabilities That Are Measured At Fair Value On A Recurring And Nonrecurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Marketable securities:
Debt securities	$ 5,729,892	$ 3,110,687
Total	6,703,423	4,959,335
Level 1
Marketable securities:
Total	968,685	1,843,822
Level 2
Marketable securities:
Total	5,734,738	3,115,513
Level 3
Marketable securities:
Total	0	0
U.S. Treasury securities
Marketable securities:
Debt securities	5,729,892	3,110,687
Cash and Cash Equivalents \| Money market funds
Cash and cash equivalents:
Cash and cash equivalents	945,330	1,823,046
Cash and Cash Equivalents \| Money market funds \| Level 1
Cash and cash equivalents:
Cash and cash equivalents	945,330	1,823,046
Cash and Cash Equivalents \| Money market funds \| Level 2
Cash and cash equivalents:
Cash and cash equivalents	0	0
Cash and Cash Equivalents \| Money market funds \| Level 3
Cash and cash equivalents:
Cash and cash equivalents	0	0
Prepaid Expenses and Other Current Assets and Other Assets \| Certificates of deposit
Prepaid expenses and other current assets and other assets:
Certificates of deposit	4,846	4,826
Prepaid Expenses and Other Current Assets and Other Assets \| Certificates of deposit \| Level 1
Prepaid expenses and other current assets and other assets:
Certificates of deposit	0	0
Prepaid Expenses and Other Current Assets and Other Assets \| Certificates of deposit \| Level 2
Prepaid expenses and other current assets and other assets:
Certificates of deposit	4,846	4,826
Prepaid Expenses and Other Current Assets and Other Assets \| Certificates of deposit \| Level 3
Prepaid expenses and other current assets and other assets:
Certificates of deposit	0	0
Marketable Securities \| U.S. Treasury securities
Marketable securities:
Debt securities	5,729,892	3,110,687
Marketable Securities \| U.S. Treasury securities \| Level 1
Marketable securities:
Debt securities	0	0
Marketable Securities \| U.S. Treasury securities \| Level 2
Marketable securities:
Debt securities	5,729,892	3,110,687
Marketable Securities \| U.S. Treasury securities \| Level 3
Marketable securities:
Debt securities	0	0
Marketable Securities \| Publicly-traded equity securities
Marketable securities:
U.S. Treasury securities	23,355	20,776
Marketable Securities \| Publicly-traded equity securities \| Level 1
Marketable securities:
U.S. Treasury securities	23,355	20,776
Marketable Securities \| Publicly-traded equity securities \| Level 2
Marketable securities:
U.S. Treasury securities	0	0
Marketable Securities \| Publicly-traded equity securities \| Level 3
Marketable securities:
U.S. Treasury securities	$ 0	$ 0