Marketable Securities

6 Months Ended

Jun. 30, 2022

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

3. Marketable securities

Marketable securities by security type consisted of the following:

	June 30, 2022
(in thousands)	Amortized cost		Gross unrealized gains		Gross unrealized losses*			Fair value
U.S. treasury bills and notes	$	215,407	$	—	$	(930	)	$	214,477
U.S. agency securities		6,203		—		(8	)		6,195
Total	$	221,610	$	—	$	(938	)	$	220,672

	December 31, 2021
(in thousands)	Amortized cost		Gross unrealized gains		Gross unrealized losses*			Fair value
U.S. treasury bills and notes	$	277,559	$	—	$	(218	)	$	277,341
U.S. agency securities		18,781		—		(10	)		18,771
Total	$	296,340	$	—	$	(228	)	$	296,112

*The Company reviews its marketable securities for impairment each period whenever the fair value of a marketable security is less than the amortized cost and evidence indicates that a marketable security’s carrying amount is not recoverable. As of June 30, 2022 and December 31, 2021, the Company expected its investments to recover through the remaining term of the security and concluded no impairment existed.

The remaining contractual maturities of all marketable securities were less than one year as of June 30, 2022 and December 31, 2021.