Investments - Summary of Available-for-Sale Investments by Security type (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Net Investment Income [Line Items]
Estimated Fair Value	$ 85,666	$ 105,442
Gross Unrealized Gains	20	32
Gross Unrealized Losses	0	0
Amortized cost	85,646	105,410
U.S. Treasuries—Cash equivalents [Member]
Net Investment Income [Line Items]
Estimated Fair Value	85,666	105,442
Gross Unrealized Gains	20	32
Gross Unrealized Losses	0	0
Amortized cost	$ 85,646	$ 105,410