The Company invests a portion of its cash in debt securities that are denominated in United States dollars. The investment portfolio consists of money market funds, asset-backed securities, commercial paper, U.S. government securities and debt securities of corporations. All of the investments are classified as available-for-sale securities and reported at fair value in the consolidated balance sheets. By the end of the third quarter of fiscal year 2022, the Company fully liquidated all of the investments and reported the remaining cash equivalents as follows:

	As of January 31, 2022
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Money market funds	$	20	$	—	$	—		$	20
Commercial paper		—		—		—			—
Corporate bonds		—		—		—			—
Asset-backed securities		—		—		—			—
U.S. government securities		—		—		—			—
Total cash equivalents and marketable debt securities	$	20	$	—	$	—		$	20

	As of January 31, 2021
	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Money market funds	$	171	$	—	$	—		$	171
Commercial paper		66,181		—		—			66,181
Corporate bonds		102,108		980		(7	)		103,081
Asset-backed securities		15,740		164		—			15,904
U.S. government securities		29,383		82		—			29,465
Total cash equivalents and marketable debt securities	$	213,583	$	1,226	$	(7	)	$	214,802

The contractual maturities of the investments at January 31, 2022 and 2021 were as follows:

The unrealized gains and losses on the available-for-sale securities were primarily caused by fluctuations in market value and interest rates as a result of the economic environment. In accordance with ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, the Company estimates the expected losses at an individual security level whenever a security’s fair value is below its amortized cost basis using the discounted cash flow method. The credit-related portion of the loss is recognized in other income, net in the consolidated statements of operations but is limited to the difference between the fair value and the amortized cost basis of the security, adjusted for accrued interest. The non-credit-related portion of the loss is recognized in accumulated other comprehensive income in the consolidated balance sheets. The credit-related losses were not material for the fiscal years ended January 31, 2022 and 2021, respectively. As of January 31, 2022, the Company fully liquidated all of its investments in debt securities and realized all of the gains and losses in the consolidated statements of operations.

The following fair value hierarchy is applied for disclosure of the inputs used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows:

Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2—Inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the assets or liabilities, either directly or indirectly through market corroboration, for substantially the full term of the financial instruments.

Level 3—Unobservable inputs based on the Company’s own assumptions used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation.

The Company measures the fair value of money market funds using quoted prices in active markets for identical assets and classifies them within Level 1. The fair value of the Company’s investments in other debt securities are obtained based on quoted prices for similar assets in active markets and are classified within Level 2.

The following tables present the fair value of the financial instruments measured on a recurring basis as of January 31, 2022 and 2021, respectively:

	As of January 31, 2022
	Total		Level 1		Level 2		Level 3
	(in thousands)
Money market funds	$	20	$	20	$	—	$	—
Commercial paper		—		—		—		—
Corporate bonds		—		—		—		—
Asset-backed securities		—		—		—		—
U.S. government securities		—		—		—		—
Total cash equivalents and marketable debt securities	$	20	$	20	$	—	$	—

	As of January 31, 2021
	Total		Level 1		Level 2		Level 3
	(in thousands)
Money market funds	$	171	$	171	$	—	$	—
Commercial paper		66,181		—		66,181		—
Corporate bonds		103,081		—		103,081		—
Asset-backed securities		15,904		—		15,904		—
U.S. government securities		29,465		—		29,465		—
Total cash equivalents and marketable debt securities	$	214,802	$	171	$	214,631	$	—