The Company’s investments consists of mutual funds held in the company’s deferred compensation plan and classified as trading securities, U.S. Treasury securities, corporate notes and bonds and U.S. Agency securities, that the Company has the intent and ability to hold to maturity and therefore, are classified as held-to-maturity. The following tables show the Company’s cash, cash equivalents, short-term and long-term investments by significant investment category as of September 30, 2018 and December 31, 2017 (in thousands):

The Company may sell certain of its investments prior to their stated maturities for strategic reasons including, but not limited to, anticipation of credit deterioration and duration management. The maturities of the Company’s long-term investments are typically less than two years.

The Company considers the declines in market value of its marketable securities investment portfolio to be temporary in nature. The Company typically invests in highly-rated securities, and its investment policy generally limits the amount of credit exposure to any one issuer. The policy generally requires investments to be investment grade, with the primary objective of minimizing the potential risk of principal loss. Fair values were determined for each individual security in the investment portfolio. When evaluating an investment for other-than-temporary impairment, the Company reviews factors such as the length of time and extent to which fair value has been below its cost basis, the financial condition of the issuer and any changes thereto, changes in market interest rates and the Company’s intent to sell, or whether it is more likely than not it will be required to sell the investment before recovery of the investment’s cost basis. As of September 30, 2018, the Company does not consider any of its investments to be other-than-temporarily impaired.