4. 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.

Unrealized gains and losses are excluded from earnings and reported as a separate component of accumulated other comprehensive income until the security is sold or matures. Gains or losses realized from sales of marketable securities are computed based on the specific identification method and recognized as a component of "Other expenses, net" in the accompanying unaudited Consolidated Statements of Operations. There were no sales of marketable securities during the three months ended December 31, 2017. During the three months ended December 31, 2018, the Company sold marketable securities with a fair value and amortized cost of $49.4 million and $49.5 million, respectively, and recognized net losses of $0.1 million. As a result, during this period, the Company collected cash proceeds of $48.9 million from the sale of marketable securities and reclassified net unrealized holding losses of $0.1 million from accumulated other comprehensive income into "Other expenses, net" in the accompanying unaudited Consolidated Statements of Operations as a result of these transactions.

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


			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Losses		Gains		Fair Value
December 31, 2018:
Corporate securities	$	2,489	$	—	$	—	$	2,489
Other debt securities		28						28
	$	2,517	$	—	$	—	$	2,517
September 30, 2018:
U.S. Treasury securities and obligations of U.S. government agencies	$	30,142	$	(65)	$	—	$	30,077
Bank certificates of deposits		5,148		—		1		5,149
Corporate securities		14,763		(30)		—		14,733
Municipal securities		2,797		(17)		—		2,780
Other debt securities		779		—		—		779
	$	53,629	$	(112)	$	1	$	53,518

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


	Fair Value
Due in one year or less	$	28
Due after one year through five years		—
Due after five years through ten years		—
Due after ten years		2,489
Total marketable securities	$	2,517

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. There were no securities in an unrealized loss position as of December 31, 2018. The aggregate fair value of the marketable securities in an unrealized loss position was $43.0 million as of September 30, 2018. Aggregate unrealized losses for these securities were insignificant as of September 30, 2018 and are presented in the table above. As of September 30, 2018, marketable securities in an unrealized loss position was comprised primarily of U.S. Treasury securities, corporate securities, and municipal securities. The securities in an unrealized loss position as of September 30, 2018 were not considered other-than-temporarily impaired and, as such, the Company did not recognize impairment losses during the period then ended. The unrealized losses were attributable to changes in interest rates that impacted the value of the investments.

Cash equivalents of less than $0.1 million and $50.6 million, respectively, at December 31, 2018 and September 30, 2018 consist of money market funds and are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices in active markets. Cash equivalents of less than $0.1 million at December 31, 2018 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.