MARKETABLE SECURITIES

Our marketable securities may consist of certificates of deposit, commercial paper, corporate bonds and government municipal bonds.

In order to estimate the fair value for each security in our investment portfolio, we obtain quoted market prices and trading activity for each security where available. We obtain relevant information from our investment advisor and, if warranted, also may review the financial solvency of certain security issuers. As of September 30, 2018, all of our 19 securities that we held were trading below our amortized cost basis. We determined each decline in value to be temporary based upon the above described factors. We expect to realize the fair value of these securities, plus accrued interest, either at the time of maturity or when the security is sold. All of our current holdings are classified as available-for-sale marketable securities and are recorded at fair value on our consolidated balance sheet with the unrealized gains and losses recorded in accumulated other comprehensive loss. All of our current marketable securities mature in less than one year and our non-current marketable securities mature in less than two years. We received proceeds from the sale of our available-for-sale marketable securities of $32.0 million, $87.1 million and $73.7 million for fiscal 2018, 2017 and 2016, respectively.

At September 30, 2018 our marketable securities consisted of (in thousands):



	Amortized Cost (1)		Unrealized Gains		Unrealized Losses			Fair Value (1)
Current marketable securities:
Certificates of deposit	$	4,756	$	—	$	(20	)	$	4,736
Total marketable securities	$	4,756	$	—	$	(20	)	$	4,736


(1)	Included in amortized cost and fair value is purchased and accrued interest of $6.

At September 30, 2017 our marketable securities consisted of (in thousands):



	Amortized Cost (1)		Unrealized Gains		Unrealized Losses			Fair Value (1)
Current marketable securities:
Corporate bonds	$	28,275	$	—	$	(20	)	$	28,255
Certificates of deposit	3,756		4		—			3,760
Current marketable securities	32,031		4		(20		)	32,015
Non-current marketable securities:
Certificates of deposit	4,757		—		(4		)	4,753
Total marketable securities	$	36,788	$	4	$	(24	)	$	36,768


(1)	Included in amortized cost and fair value is purchased and accrued interest of $211.

The following tables show the fair values and gross unrealized losses of our available-for-sale securities that have been in a continuous unrealized loss position deemed to be temporary, aggregated by investment category (in thousands):



	September 30, 2018
	Less than 12 Months				More than 12 Months
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Certificates of deposit	$	—	$	—	$	4,736	$	(20	)
Total	$	—	$	—	$	4,736	$	(20	)

7. MARKETABLE SECURITIES (CONTINUED)



	September 30, 2017
	Less than 12 Months					More than 12 Months
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Corporate bonds	$	26,196	$	(20	)	$	—	$	—
Certificates of deposit	3,751		(4		)	—		—
Total	$	29,947	$	(24	)	$	—	$	—