Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Financial Instruments (Excluding Restricted Cash) Measured at Fair Value on Recurring Basis

The following tables set forth the Company’s financial instruments (excluding restricted cash) that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):

	December 31, 2021
	Total		Level 1		Level 2		Level 3
Money market funds	$	147,914	$	147,914	$	-	$	-
U.S. treasury securities		112,170		-		112,170		-
Corporate securities and commercial paper		421,214		-		421,214		-
Total assets measured at fair value	$	681,298	$	147,914	$	533,384	$	-

	December 31, 2020
	Total		Level 1		Level 2		Level 3
Money market funds	$	146,468	$	146,468	$	-	$	-
U.S. treasury securities		301,112		-		301,112		-
U.S. Government agency obligations		25,001		-		25,001
Corporate securities and commercial paper		262,505		-		262,505		-
Total assets measured at fair value	$	735,086	$	146,468	$	588,618	$	-

Schedule of Investments Classified as Available for Sale Securities with Contractual Maturities

The Company's investments are classified as (with contractual maturities):

	Year Ended December 31,
	2021		2020
Cash and cash equivalents	$	147,914	$	173,415
Short-term investments (due within one year)		351,394		555,231
Long-term investments (due between one and three    years)		181,990		6,440
	$	681,298	$	735,086

Schedule of Fair Value and Amortized Cost of Investments in Marketable Securities by Major Security Type

The fair value and amortized cost of investments in marketable securities by major security type as of December 31, 2021 and 2020 are presented in the tables that follow (in thousands):

	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
As of December 31, 2021:
Money market funds	$	147,914	$	-	$	-		$	147,914
U.S. treasury securities		112,473		1		(304	)		112,170
Corporate securities and commercial paper		422,172		3		(961	)		421,214
Total	$	682,559	$	4	$	(1,265	)	$	681,298

	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
As of December 31, 2020:
Money market funds	$	146,468	$	-	$	-		$	146,468
U.S. treasury securities		301,075		38		(1	)		301,112
U.S. government agency obligations		24,997		4		-			25,001
Corporate securities and commercial paper		262,502		15		(12	)		262,505
Total	$	735,042	$	57	$	(13	)	$	735,086