3. Marketable Securities

The Company invests in marketable securities that are classified as available-for-sale and records them at fair value in the Company’s unaudited Consolidated Balance Sheets. Marketable securities reported as current assets represent investments that mature within one year from the balance sheet date. Long-term marketable securities represent investments with maturity dates greater than one year from the balance sheet date. The securities are valued using matrix pricing and benchmarking and classified within Level 2 of the fair value hierarchy because they are not actively traded. Matrix pricing is a mathematical technique used to value securities by relying on the securities’ relationship to other benchmark quoted prices.

The following is a summary of the amortized cost and the fair value, including accrued interest receivable, as well as unrealized holding gains (losses) on the short-term and long-term marketable securities as of March 31, 2018 and September 30, 2017 (in thousands):


			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Losses		Gains		Fair Value
March 31, 2018 :
U.S. Treasury securities and obligations of U.S. government agencies	$	31,870	$	(56)	$	—	$	31,814
Bank certificates of deposits		6,158		—		2		6,160
Corporate securities		6,426		(17)		—		6,409
Municipal securities		6,761		(10)		—		6,751
Other debt securities		29		—		—		29
	$	51,244	$	(83)	$	2	$	51,163
September 30, 2017 :
Corporate securities	$	2,642	$	—	$	—	$	2,642
Other debt securities		28		—		—		28
	$	2,670	$	—	$	—	$	2,670

The fair values of the marketable securities by contractual maturities at March 31, 2018 are presented below (in thousands):


	Fair Value
Due in one year or less	$	40,655
Due after one year through five years		7,785
Due after five year through ten years		—
Due after ten years		2,723
Total marketable securities	$	51,163

Expected maturities could differ from contractual maturities because the security issuers may have the right to prepay obligations without prepayment penalties.

The Company reviews the marketable securities for impairment at each reporting period to determine if any of the securities have experienced an other-than-temporary decline in fair value. The Company considers factors, such as the length of time and extent to which the market value has been less than the cost, the financial condition and near-term prospects of the issuer, 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 its amortized cost basis. If the Company believes that an other-than-temporary decline in fair value has occurred, it writes down the investment to its fair value and recognizes the credit loss in earnings and the non-credit loss in accumulated other comprehensive income or loss. As of March 31, 2018, the aggregate fair value of the marketable securities in an unrealized loss position was $39.7 million and was comprised of U.S. Treasury securities and obligations of U.S. government agencies, U.S. corporate securities, municipal securities and bank certificates of deposits. There were no marketable securities in an unrealized loss position as of September 30, 2017.

Cash equivalents of $51.2 million and less than $0.1 million, respectively, at March 31, 2018 and September 30, 2017 consist of money market funds and are classified within Level 1 of fair value hierarchy because they are valued using quoted market prices in active markets. Cash equivalents of $0.5 million and less than $0.1 million, respectively at March 31, 2018 and September 30, 2017 consist primarily of bank certificates of deposits with original maturities of less than 90 days and are classified within Level 2 of the fair value hierarchy because they are not actively traded.