3.  CASH, CASH EQUIVALENTS, INVESTMENTS AND RESTRICTED CASH

The following is a summary of the Company’s cash, cash equivalents and debt investments (in thousands): 

The following table summarizes the contractual maturities of the short-term and long-term available-for-sale investments as of December 31, 2022 (in thousands): 

For the year ended December 31, 2020, the Company recognized gross realized gains of $1.1 million on the sale of investments. Gross realized gains and losses were not material for the other periods presented.

The following tables summarize the unrealized gain and loss positions related to the available-for sale investments (in thousands): 

The following tables present information about the available-for-sale investments that had been in a continuous unrealized loss position for less than 12 months and for greater than 12 months (in thousands):

An impairment exists when the fair value of an investment is less than its amortized cost basis. As of December 31, 2022 and 2021, the Company did not consider the impairment of its investments to be a result of credit losses. The Company typically invests in highly rated securities, with the primary objective of minimizing the potential risk of principal loss. The Company’s investment policy generally requires securities to be investment grade and limits the amount of credit exposure to any one issuer. When evaluating a debt security for impairment, management reviews factors such as the Company’s intent to sell, or whether it will more likely than not be required to sell, the security before recovery of its amortized cost basis, the extent to which the fair value of the security is less than its cost, the financial condition of the issuer and the credit quality of the investment.

The Company’s auction-rate securities are backed by pools of student loans supported by guarantees by the U.S. Department of Education. The underlying maturities of these securities are up to 23 years. The Company has received all scheduled interest payments on a timely basis pursuant to the terms and conditions of the securities. The Company does not intend to sell these securities, and it is more likely than not that the Company will not be required to sell these securities, before recovery of its amortized cost basis. To date, the Company has redeemed $41.5 million, or 96% of the original portfolio in these auction-rate securities, at par without any realized losses.

Non-Marketable Equity Investment

In November 2020, the Company made an equity investment in a privately held Swiss company (the “Investee”) that is accounted for under the measurement alternative. In  April 2022, the Company made an investment in a convertible loan that will convert into additional shares of the Investee. One member of the Company’s Board of Directors is an executive officer of a company that has a commercial relationship with the Investee. In addition, the Company’s Chief Executive Officer has a personal investment in the Investee and is on the Investee’s board of directors. As of December 31, 2022 and 2021, the Company’s investment in the Investee, which is denominated in Swiss Franc, had a carrying value of $5.4 million and $3.3 million, respectively. The Company did not record any impairment or adjustments resulting from observable price changes for the years ended December 31, 2022 and 2021.

Restricted Cash

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported on the Consolidated Balance Sheets to the amounts reported on the Consolidated Statements of Cash Flows (in thousands):   

As of  December 31, 2022 and 2021, restricted cash included a security deposit that is set aside in a bank account and cannot be withdrawn by the Company under the terms of a lease agreement. The restriction will end upon the expiration of the lease.