5. Financial Instruments

The Company elected to invest a portion of its cash assets in conservative, income earning, and liquid investments. Cash, cash equivalents, restricted cash and investments, which are classified as available-for-sale securities, consisted of the following:

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The Company invests in U.S. Treasuries, U.S. agency and high-quality municipal bonds which mature at par value and are all paying their coupons on schedule. The Company has therefore concluded an allowance for expected credit losses of its investments was not necessary and will continue to recognize unrealized gains and losses in other comprehensive income (loss). During the three months ended March 31, 2024 and March 31, 2023, the Company did not sell any investments. The Company uses the specific investment identification method to calculate realized gains and losses and amounts reclassified out of other comprehensive income (loss) to net loss. As of March 31, 2024, the Company had 14 investments in an unrealized loss position in its portfolio. Gross unrealized losses were not material as of March 31, 2024. Gross unrealized losses were primarily due to declines in the value of fixed rate instruments as interest rates in the broader market increased, and were not indictive of a decline in the credit worthiness of the underlying issuer, and as such, the Company did not record a credit loss reserve as of March 31, 2024.

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The following table presents debt securities available-for-sale that were in an unrealized loss position as of March 31, 2024, aggregated by major security type in a continuous loss position. There were no debt securities available-for-sale in an unrealized loss position for less than 12 months as of March 31, 2024.

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The following table summarizes the Company’s portfolio of available-for-sale securities by contractual maturity as of March 31, 2024:

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