4. Fair Value Measurements

Fair Value Measurements of Assets and Liabilities

The following tables set forth our financial assets and liabilities that were accounted for at fair value on a recurring basis as of January 31, 2015 and January 31, 2014:

Available-for-Sale Securities

We determine the appropriate classification of debt securities at the time of purchase and reevaluate such designation as of each balance sheet date. Our investment portfolio consists of money market funds, U.S. treasury notes and bonds, and U.S. government agency notes and bonds as of January 31, 2015 and 2014. All highly liquid investments with an original maturity of three months or less when purchased are considered to be cash equivalents. All cash equivalents are carried at cost, which approximates fair value. Our marketable securities are classified as available-for-sale and are reported at fair value with unrealized gains and losses, net of tax, reported in stockholders’ equity as a component of accumulated other comprehensive loss. The amortization of premiums and accretion of discounts to maturity are computed under the effective interest method and is included in other expenses, net. Interest on securities is recorded as earned and is also included in other expenses, net. Any realized gains or losses would be shown in the accompanying consolidated statements of operations and comprehensive loss in other expenses, net.

The following is a summary of cash, cash equivalents and available-for-sale securities, including the cost basis, aggregate fair value and unrealized gains and losses, for short-and long-term marketable securities portfolio as of January 31, 2015 and 2014:

The gross realized gains and losses on sale of available-for-sale securities for fiscal years 2015, 2014 and 2013 were immaterial. For purposes of determining gross realized gains and losses, the cost of securities sold is based on specific identification.

Contractual maturities of available-for-sale debt securities at January 31, 2015 are as follows (amounts in thousands):

We concluded that there were no other than temporary declines in investments recorded as of January 31, 2015, 2014 and 2013. The unrealized holding gains (losses), net of tax, on available-for-sale securities, which are not material for the periods presented, have been included in stockholders’ equity as a component of accumulated other comprehensive loss.

Cash, Cash Equivalents and Marketable Securities

Cash and cash equivalents consist primarily of highly liquid investments in money market mutual funds, government sponsored enterprise obligations, treasury bills, commercial paper and other money market securities with remaining maturities at date of purchase of 90 days or less.

Restricted Cash

In December 2014, in conjunction with our acquisition of TLL, LLC (“Timeline Labs”), we entered into an agreement to fund a $2.5 million escrow from which Timeline Labs could make withdrawals for working capital purposes. The withdrawn portion of the escrow is accounted for as an advance against the purchase price and is recorded in other assets on our consolidated balance sheets. The unused portion, being $1.1 million remaining in escrow after signing the related merger agreement but prior to the consummation of the acquisition on February 2, 2015, is classified as restricted cash on our consolidated balance sheets. See Note 16., “Subsequent Events,” for additional information.

The fair value of cash, cash equivalents, restricted cash and marketable securities at January 31, 2015 and 2014 was $105.4 million and $128.1 million, respectively.