Cash and investments in marketable securities, including cash equivalents, are as follows (in thousands):


	Estimated Fair Value at
	December 31,		December 31,
	2024		2023
Cash and cash equivalents	$	44,252	$	35,277
Short-term investments		210,974		268,339
Long-term investments		13,869		25,825
Total cash and investments in marketable securities	$	269,095	$	329,441

We invest in liquid, high quality debt securities. Our investments in debt securities are subject to interest rate risk. To minimize the exposure due to an adverse shift in interest rates, we invest in securities with maturities of two years or less and maintain a weighted average maturity of one year or less. All of our long-term investments as of December 31, 2024 had maturities between one and two years. We currently do not intend to sell these securities prior to maturity and it is more likely than not that we will not be required to sell these securities before we recover the amortized cost basis.

During the years ended December 31, 2024 and 2023, we did not sell any available-for-sale securities.

We report our accrued interest receivable, which totaled $1.1 million and $0.5 million at December 31, 2024 and December 31, 2023, respectively, in other current assets on our Consolidated Balance Sheets.

Our portfolio of cash and investments in marketable securities includes (in thousands):


				December 31, 2024							December 31, 2023
	Fair Value Hierarchy Level	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Fair Value
Corporate notes and bonds	2	$	109,678	$	100	$	(67	)	$	109,711	$	38,882
Corporate commercial paper	2		119,540		58		(56	)		119,542		255,241
Available-for-sale investments			229,218		158		(123	)		229,253		294,123
Money market funds	1									15,993		2,359
Certificates of deposit	2									14,027		15,116
Cash	N/A									9,822		17,843
Total cash and investments in marketable securities									$	269,095	$	329,441

At December 31, 2023, our gross unrealized gains and losses were insignificant. As of December 31, 2024 and 2023, we assessed our marketable securities with unrealized losses and concluded that the losses were not attributable to credit. As of December 31, 2024, we had 39 investments in unrealized loss positions and no investments had been in continuous unrealized loss positions for 12 months or longer. Accordingly, we have not recorded an allowance for credit losses for these securities.

At both December 31, 2024 and 2023, we had letter of credit arrangements in favor of our landlords and certain vendors totaling $7.5 million and $7.5 million, respectively. These letters of credit are secured by investments of similar amounts.