Cash, Cash Equivalents, Restricted Cash and Marketable Securities

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Cash, Cash Equivalents, Restricted Cash and Marketable Securities

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows:


	December 31
	2021		2020		2019
Cash and cash equivalents	$	436,189	$	32,073	$	39,884
Restricted cash		219		237		216
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	$	436,408	$	32,310	$	40,100

Restricted cash balances relate to certificates of deposit issued as collateral to certain letters of credit issued as security to our lease arrangements. See Note 8.

Cash, cash equivalents and marketable securities consist of the following (in thousands):


	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
December 31, 2021
Cash and cash equivalents:
Cash	$	6,995	$	-	$	-		$	6,995
Money market funds		429,194		-		-			429,194
Total cash and cash equivalents		436,189		-		-			436,189
Marketable securities available-for-sale:
U.S. treasuries		4,005		-		(1	)		4,004
U.S. government agency securities		26,555		-		(7	)		26,548
Corporate debt securities		79,200		9		-			79,209
Total marketable securities available-for-sale		109,760		9		(8	)		109,761
Total cash, cash equivalents and marketable securities	$	545,949	$	9	$	(8	)	$	545,950
December 31, 2020
Cash and cash equivalents:
Cash	$	7,945	$	-	$	-		$	7,945
Money market funds		23,128		-		-			23,128
Corporate debt securities		1,000		-		-			1,000
Total cash and cash equivalents		32,073		-		-			32,073
Marketable securities available-for-sale:
U.S. treasuries		32,548		31		-			32,579
U.S. government agency securities		40,313		14		(6	)		40,321
Corporate debt securities		60,071		3		(11	)		60,063
Total marketable securities available-for-sale		132,932		48		(17	)		132,963
Total cash, cash equivalents and marketable securities	$	165,005	$	48	$	(17	)	$	165,036

The maturities of our marketable securities available-for-sale are as follows (in thousands):


.	December 31, 2021
	Amortized Cost		Estimated Fair Value
Mature in one year or less	$	109,760	$	109,761
Mature after one year through two years		-		-
	$	109,760	$	109,761

There were no gross realized gains or losses on investments for each of the year ended December 31, 2021 and 2019. For the year ended December 31, 2020, there were gross realized gains on investments of $0.1 million and no gross realized losses. Realized gains are included in interest income in the consolidated statements of operations. All investments with unrealized losses at December 31, 2021 have been in a loss position for less than twelve months. We do not intend to sell the investments that are in an unrealized loss position before recovery of their amortized cost basis. To date, there have been no declines in fair value that have been identified as other than temporary.