3. Cash Equivalents and Restricted Securities

The following is a summary of cash equivalents and restricted securities (in thousands):


			Unrealized		Estimated
			Holding		Market
March 31, 2017	Cost Basis		Gains		Value
Cash equivalents:
Money market funds	$	3,469	$	--	$	3,469
Restricted securities:
Money market funds		713		--		713

			Unrealized		Estimated
			Holding		Market
December 31, 2016	Cost Basis		Gains		Value
Cash equivalents:
Money market funds	$	3,466	$	--	$	3,466
Restricted securities:
Money market funds		699		--		699

As of March 31, 2017 and December 31, 2016 $713,000 and $699,000, respectively, of the Company’s 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 in the three months ended March 31, 2017 and 2016. As of March 31, 2017 $216,000 of the Company’s restricted securities had a maturity date within three months and $497,000 had a maturity date between three months and one year. As of December 31, 2016 $490,000 of the Company’s restricted securities had a maturity date within three months and $209,000 had a maturity date between three months and one year.