Investment Securities (Tables)

6 Months Ended

Jun. 30, 2022

Investments, Debt and Equity Securities [Abstract]

Disclosure - Investment Securities - Summary of Cost, Gross Unrealized Holding Gains and Losses, Allowances for Credit Losses and Fair Value of Available-for-Sale Investments by Types, Maturities and Classes of Securities (Detail)

The cost, gross unrealized holding gains, gross unrealized holding

losses, allowances for credit losses and fair value of available-for-sale investments by types, maturities and classes of securities at June 30, 2022 and December 31, 2021 consisted of the following (in thousands):

		As of June 30, 2022
											Estimated
									Allowance		Fair
		Amortized		Unrealized		Unrealized			for Credit		Market
	Maturity	Cost		Gains		Losses			Losses		Value
Certificates of deposits	Within 1 year	$	3,817	$	—	$	(50	)	$	—	$	3,767
U.S. Treasury securities	Within 1 year		162,295		—		(1,241	)		—		161,054
Certificates of deposits	1 year to 2 years		1,951		—		(26	)		—		1,925
U.S. Treasury securities	1 year to 2 years		73,975		—		(998	)		—		72,977
Total		$	242,038	$	—	$	(2,315	)	$	—	$	239,723
		As of December 31, 2021
											Estimated
									Allowance		Fair
		Amortized		Unrealized		Unrealized			for Credit		Market
	Maturity	Cost		Gains		Losses			Losses		Value
Certificates of deposits	Within 1 year	$	2,896	$	—	$	(3	)	$	—	$	2,893
U.S. Treasury securities	Within 1 year	$	15,045		—		(23	)			$	15,022
Certificates of deposits	1 year to 2 years	$	2,887		—		(9	)			$	2,878
U.S. Treasury securities	1 year to 2 years		64,911		—		(209	)		—		64,702
Total		$	85,739	$	—	$	(244	)	$	—	$	85,495