Fair Value of Financial Instruments - Schedule of Major Categories of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Certificates of Deposit [Member]
Assets:
Assets		$ 25.0
U.S. Treasury Securities [Member]
Assets:
Assets	$ 24.7	173.6
Level 2 [Member] | Certificates of Deposit [Member]
Assets:
Assets		25.0
Level 2 [Member] | U.S. Treasury Securities [Member]
Assets:
Assets	$ 24.7	$ 173.6