Short-Term Investments (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of Estimated Fair Value of Short-Term Investments

The following represents a summary of the estimated fair value of short-term investments at December 31, 2021 and 2020 (in thousands):

At December 31, 2021	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Estimated Fair Value
Available-for-sale securities:
U.S. Treasury securities	$	222,206	$	—	$	(482)	$	221,724
Commercial paper	218,391		14		(24)		218,381
Corporate debt securities	58,881		—		(45)		58,836
U.S. Government-sponsored enterprises	50,773		1		(88)		50,686
Supranational bonds	3,003		—		—		3,003
Total	$	553,254	$	15	$	(639)	$	552,630

At December 31, 2020	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Estimated Fair Value
Available-for-sale securities:
U.S. Treasury securities	$	143,244	$	12	$	(2)	$	143,254
Commercial paper	108,892		5		(1)		108,896
Corporate debt securities	85,788		48		(13)		85,823
U.S. Government-sponsored enterprises	52,330		21		(1)		52,350
Total	$	390,254	$	86	$	(17)	$	390,323

Schedule of Contractual Maturities of Available - For- Sale Debt Securities

The contractual maturities of available-for-sale debt securities as of December 31, 2021, were as follows (in thousands):

	Years to Maturity
At December 31, 2021	Within One Year		One to Two Years		Estimated Fair Value
U.S. Treasury securities	$	105,231	$	116,493	$	221,724
Commercial paper	218,381		—		218,381
Corporate debt securities	58,836		—		58,836
U.S. Government-sponsored enterprises	32,282		18,404		50,686
Supranational bonds	3,003		—		3,003
Total	$	417,733	$	134,897	$	552,630