Marketable Securities (Tables)

6 Months Ended

Mar. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Summary of Amortized Cost and Fair Value, Including Accrued Interest Receivable and Unrealized Holding Gains (Losses) on Short-term and Long-term Marketable Securities

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 March 31, 2019 and September 30, 2018 (in thousands):

			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Losses		Gains		Fair Value
March 31, 2019:
Bank certificates of deposits	$	2	$	—	$	—	$	2
Corporate securities		2,795		—		—		2,795
Other debt securities		45						45
	$	2,842	$	—	$	—	$	2,842
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

Fair Value of Marketable Securities by Contractual Maturity

The fair values of the marketable securities by contractual maturities at March 31, 2019 are presented below (in thousands):

	Fair Value
Due in one year or less	$	47
Due after one year through five years		—
Due after five years through ten years		—
Due after ten years		2,795
Total marketable securities	$	2,842