3. AVAILABLE-FOR-SALE SECURITIES

The following table is a summary of available-for-sale debt and equity securities recorded in cash equivalents or marketable securities in our Condensed Consolidated Balance Sheets. Estimated fair values of available-for-sale securities are generally based on prices obtained from commercial pricing services (in thousands):

The following table summarizes the classification of the available-for-sale debt and equity securities on our Condensed Consolidated Balance Sheets (in thousands):

The following table summarizes our portfolio of available-for-sale debt securities by contractual maturity (in thousands):

The following table summarizes the gross realized gains and losses related to sales of marketable securities (in thousands):

The cost of securities sold was determined based on the specific identification method.

The following table summarizes our available-for-sale debt securities that were in a continuous unrealized loss position, but were not deemed to be other-than-temporarily impaired (in thousands):

As of September 30, 2011 and December 31, 2010, approximately 31% and 34%, respectively, of the total number of securities were in an unrealized loss position. The gross unrealized losses for auction rate securities were caused by a higher discount rate used in the valuation of these securities as compared to the coupon rates of these securities. The gross unrealized losses for the other securities were primarily the result of a lack of market activity and liquidity of the underlying securities. No significant facts or circumstances have arisen to indicate that there has been any deterioration in the creditworthiness of the issuers of these securities. Based on our review of these securities, we believe we had no other-than-temporary impairments on these securities as of September 30, 2011 and December 31, 2010 because we do not intend to sell these securities and it is not more likely than not that we will be required to sell these securities before the recovery of their amortized cost basis.

During the three and nine months ended September 30, 2011, we recorded net unrealized losses on available-for-sale securities of $24.8 million and $24.1 million, respectively, in accumulated other comprehensive income (OCI) and reclassified gains of $2.6 million and $7.2 million, respectively, out of accumulated OCI into interest and other income, net. Comparatively, during the three and nine months ended September 30, 2010, we recorded net unrealized gains on available-for-sale securities of $9.7 million and $18.4 million, respectively, in accumulated OCI and reclassified gains of $1.0 million and $5.0 million, respectively, out of accumulated OCI into interest and other income, net.