4. Cash Equivalents and Marketable Securities

Cash equivalents and marketable securities consisted of the following:

As of December 31, 2019, $15.6 million of marketable securities had maturities of more than one year and are classified as long-term assets.  As of December 31, 2018, no marketable securities had maturities of more than one year.

There were $4.5 million and $52.6 million of investments in an unrealized loss position as of December 31, 2019 and December 31, 2018, respectively. During the years ended December 31, 2019 and 2018 the Company did not record any other-than-temporary impairment charges on its available-for-sale securities. Based upon the Company’s impairment review, the Company determined that the unrealized losses were not attributed to credit risk but were primarily associated with changes in interest rates. Based on the scheduled maturities of the investments, the Company was more likely than not to hold these investments for a period of time sufficient for a

recovery of the Company’s cost basis.  As such, the Company concluded that the unrealized losses in the investment securities were not other-than-temporary.