9.     Cash, Cash Equivalents and Available-For-Sale Securities

Cash, cash equivalents and available-for-sale securities consisted of the following (in thousands):

Cash equivalents and available-for-sale securities include the following securities with unrealized gains and losses (in thousands):

As of June 30, 2013, the contractual maturities of our cash equivalents and available-for-sale securities were (in thousands):

As of June 30, 2013, our cash equivalents and available-for-sale securities had a weighted average time to maturity of 235 days. We view our available-for-sale portfolio as available for use in current operations.  Accordingly, we have classified certain investments as available-for-sale securities on our balance sheet even though the stated maturity date of these securities may be more than one year from the current balance sheet date. We have the ability to hold all investments as of June 30, 2013 to maturity. In the second quarter of 2013, we sold certain available-for-sale securities at their approximate carrying values prior to maturity and received proceeds of $16.5 million. The cost of securities we sell is determined based on the specific identification method. At June 30, 2013 and December 31, 2012, we had no investments that had been in a continuous unrealized loss position for more than 12 months.  As of June 30, 2013, a total of 44 individual securities had been in an unrealized loss position for 12 months or less and the losses were determined to be temporary.

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):