Cash Equivalents And Restricted Cash And Securities	12 Months Ended
	Dec. 31, 2021
Cash Equivalents And Restricted Cash And Securities [Abstract]
Cash Equivalents And Restricted Cash And Securities	6. Cash Equivalents and Restricted Cash and Securities The following is a summary of cash equivalents and marketable securities (in thousands): Unrealized Estimated Holding MarketDecember 31, 2021Cost Basis Gains ValueCash equivalents: Money market funds$ 10,015 -- $ 10,015Total assets$ 10,015 $ -- $ 10,015 Unrealized Estimated Holding MarketDecember 31, 2020Cost Basis Gains ValueCash equivalents: Money market funds$ 11,484 -- $ 11,484Restricted securities: Money market funds 546 -- 546Total assets$ 12,030 $ -- $ 12,030 As of December 31, 2020 $546,000 of our money market funds were designated as short-term restricted securities due to a contractual commitment to hold the securities as pledged collateral relating primarily to international tax obligations. There were no gross realized gains or losses on cash equivalents or restricted securities for the years ended December 31, 2021, 2020, and 2019. As of December 31, 2020 $546,000 of our restricted securities had a maturity date within three months.