Marketable Securities (Tables)

12 Months Ended

Sep. 30, 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, as well as unrealized holding gains (losses) on the short-term and long-term marketable securities as of September 30, 2019 and 2018 (in thousands):

			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Losses		Gains		Fair Value
September 30, 2019:
U.S. Treasury securities and obligations of U.S. government agencies	$	31,863	$	(2)	$	5	$	31,866
Bank certificates of deposits		750		—		—		750
Corporate securities		4,317		—		1		4,318
Other debt securities		35		—		—		35
	$	36,965	$	(2)	$	6	$	36,969
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 September 30, 2019 are presented below (in thousands).

	Fair Value
Due in one year or less	$	34,124
Due after one year through five years		—
Due after five years through ten years		—
Due after ten years		2,845
Total marketable securities	$	36,969