Assets and Liabilities that are Measured at Fair Value on a Recurring Basis

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, 2018 and January 31, 2017. There were no fair value measurements of our financial assets and liabilities using significant level 3 inputs for the periods presented:

Assets and Liabilities that are Measured at Fair Value on a Nonrecurring Basis

Assets and liabilities that are measured at fair value on a nonrecurring basis relate primarily to our tangible property and equipment, goodwill, and other intangible assets, which are re-measured when the derived fair value is below carrying value on our consolidated balance sheets. For these assets and liabilities, we do not periodically adjust carrying value to fair value except in the event of impairment. If we determine that impairment has occurred, the carrying value of the asset is reduced to fair value and the difference is recorded to loss from impairment of long-lived assets in our consolidated statements of operations and comprehensive income (loss).

Available-for-Sale Securities

We determine the appropriate classification of debt investment 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, U.S. government agency notes and bonds as of January 31, 2018 and 2017, and corporate bonds as of January 31, 2018. All highly liquid investments with an original maturity of three months or less when purchased are 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 accretions of discounts to maturity are computed under the effective interest method and is included in other income (expenses), net, in our consolidated statements of operations and comprehensive income (loss). Interest on securities is recorded as earned and is also included in other income (expenses), net. Any realized gains or losses would be shown in the accompanying consolidated statements of operations and comprehensive income (loss) in other income (expenses), net. We provide fair value measurement disclosures of available-for-sale securities in accordance with one of three levels of fair value measurement mentioned above.

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, 2018 and 2017:

The gross realized gains and losses on sale of available-for-sale securities for fiscal 2018, 2017 and 2016 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, 2018 are as follows (amounts in thousands):

We concluded that there were no other-than-temporary declines of available-for-sale securities as of January 31, 2018, 2017 and 2016. The unrealized holding 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.

The fair value of cash, cash equivalents, restricted cash and marketable securities at January 31, 2018 and 2017 was $52.1 million and $38.7 million, respectively.

Restricted Cash

At times, we may be required to maintain cash held as collateral for performance obligations with our customers which we classify as restricted cash on our consolidated balance sheets. Restricted cash was not material as of January 31, 2018 and was $0.1 million as of January 31, 2017.