10.Cash, Cash Equivalents and Short-Term Investments

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Cash, cash equivalents and short-term investments consisted of the following (in thousands):

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Cash equivalents and short-term investments include the following securities with gross unrealized gains and losses (in thousands):

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As of March 31, 2021 and December 31, 2020, our cash equivalents and short-term investments, which have contractual maturities within one year, had a weighted-average time to maturity of approximately 39 days and 78 days, respectively. We view our short-term investments portfolio as available for use in current operations. We have the ability to hold all investments as of March 31, 2021 through their respective maturity dates. As of March 31, 2021, we had no investments that had been in a continuous unrealized loss position for more than 12 months. As of March 31, 2021, a total of 18 individual securities had been in an unrealized loss position for 12 months or less, and the losses were determined to be temporary. The gross unrealized losses above were caused by interest rate increases. No significant facts or circumstances have arisen to indicate that there has been any significant deterioration in the creditworthiness of the issuers of the securities held by us. Based on our review of these securities, including the assessment of the duration and severity of the unrealized losses and our ability and intent to hold the investments until maturity, there were no other-than-temporary impairments for these securities as of March 31, 2021.

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The following table shows the fair value and gross unrealized losses of our investments in individual securities that are in an unrealized loss position, aggregated by investment category (in thousands):

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