Marketable Securities

Marketable securities consist of the following for the periods presented (in thousands):


	April 30, 2024
	Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Total Estimated Fair Value
U.S. government securities	$	319,622	$	—	$	(1,915)	$	317,707
Foreign securities	6,347		7		(45)		6,309
Corporate debt securities	85,228		31		(318)		84,941
Total	$	411,197	$	38	$	(2,278)	$	408,957


	January 31, 2024
	Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Total Estimated Fair Value
U.S. government securities	$	319,343	$	782	$	(1,168)	$	318,957
Foreign securities	6,349		31		(13)		6,367
Corporate debt securities	82,368		340		(134)		82,574
Total	$	408,060	$	1,153	$	(1,315)	$	407,898

Accrued interest receivables related to our available-for-sale securities of $3.6 million as of April 30, 2024, and $3.4 million as of January 31, 2024, were included within prepaid expenses and other current assets on the consolidated balance sheets.

The Company’s short-term investments consist of available-for-sale debt securities and term deposits. The term deposits are at cost, which approximates fair value. The weighted-average remaining maturity of the Company’s investment portfolio is one and a half years as of the periods presented.

The following table summarizes the fair value and gross unrealized losses aggregated by category of individual securities that have been in a continuous unrealized loss position for greater than 12 months (in thousands):


	April 30, 2024
	Continuous Unrealized Loss for Greater than 12 months
	Estimated Fair Value		Gross Unrealized Losses
U.S. government securities	$	76,134	$	(315)
Foreign securities	1,328		(8)
Corporate debt securities	6,477		(20)
Total	$	83,939	$	(343)

No individual security incurred continuous unrealized losses for greater than 12 months as of April 30, 2023.

The Company purchases investment grade marketable debt securities which are rated by nationally recognized statistical credit rating organizations in accordance with its investment policy. This policy is designed to minimize the Company's exposure to credit losses. As of April 30, 2024, the credit-quality of the Company’s marketable available-for-sale debt securities had remained stable. The unrealized losses recognized on marketable available-for-sale debt securities as of April 30, 2024 was primarily related to the continued market volatility associated with market expectations of an aggressive pace of interest rate increases by the Federal Reserve. The contractual terms of these investments do not permit the issuer to settle the securities at a price less than the amortized cost basis of the investments and it is not expected that the investments would be settled at a price less than their amortized cost basis. The Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis. The Company is not aware of any specific event or circumstance that would require the Company to change its assessment of credit losses for any marketable available-for-sale debt security as of April 30, 2024. These estimates may change, as new events occur and additional information is obtained, and will be recognized on the consolidated financial statements as soon as they become known. No credit losses were recognized as of April 30, 2024 for the Company’s marketable debt securities.

The contractual maturities of the investments classified as available-for-sale marketable securities are as follows (in thousands):


	April 30, 2024
	Amortized Cost		Estimated Fair Value
Due within 1 year	$	189,065	$	187,947
Due in 1 year through 5 years	222,132		221,010
Total	$	411,197	$	408,957


	January 31, 2024
	Amortized Cost		Estimated Fair Value
Due within 1 year	$	173,481	$	172,520
Due in 1 year through 5 years	234,579		235,378
Total	$	408,060	$	407,898

Investment income consists of interest income and accretion income/amortization expense on our cash, cash equivalents, restricted cash, and marketable securities. Investment income is included within other income, net on the consolidated statements of operations. The primary components of investment income from marketable securities were as follows (in thousands):


	Three Months Ended April 30,
	2024		2023
Interest income	$	4,160	$	2,928
Accretion/amortization of discount/premium, net	487		471
Investment income	$	4,647	$	3,399