Marketable Securities (Tables)

12 Months Ended

Sep. 30, 2021

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, 2021 and 2020 (in thousands):

			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Losses		Gains		Fair Value
September 30, 2021:
Bank certificates of deposits	$	30	$	—	$	—	$	30
Corporate securities		3,624		—		—		3,624
Municipal securities		25		—		—		25
	$	3,679	$	—	$	—	$	3,679
September 30, 2020:
Bank certificates of deposits	$	51	$	—	$	—	$	51
Corporate securities		3,101		—		—		3,101
Other debt securities		16		—		—		16
	$	3,168	$	—	$	—	$	3,168

Fair Value of Marketable Securities by Contractual Maturity

The fair values of the marketable securities by contractual maturities at September 30, 2021 are presented below (in thousands).

	Fair Value
Due in one year or less	$	81
Due after one year through five years		—
Due after five years through ten years		—
Due after ten years		3,598
Total marketable securities	$	3,679