Note 4 - Marketable Securities

3 Months Ended

Dec. 31, 2024

Notes to Financial Statements

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]

4. Marketable Securities

The Company had sales and maturities of marketable securities of $125.6 million and $110.3 million in the three months ended December 31, 2024 and 2023, respectively. There were immaterial realized gains in the three months ended  December 31, 2024 and 2023 on sales and maturities of marketable securities. 

The following is a summary of the amortized cost and the fair value, including accrued interest receivable as well as unrealized gains (losses) on the short-term and long-term marketable securities as of December 31, 2024 and  September 30, 2024 (in thousands):

			Gross			Gross
	Amortized		Unrealized			Unrealized
	Cost		Losses			Gains		Fair Value
December 31, 2024:
U.S. Treasury securities and obligations of U.S. government agencies	$	68,189	$	(83	)	$	9	$	68,115
Bank certificates of deposit		2,229		(6	)		—		2,223
Corporate securities		42,634		(116	)		—		42,518
Municipal securities		528		—			—		528
	$	113,580	$	(205	)	$	9	$	113,384
September 30, 2024:
U.S. Treasury securities and obligations of U.S. government agencies	$	118,159	$	(119	)	$	51	$	118,091
Bank certificates of deposit		5,212		(13	)		1		5,200
Corporate securities		77,580		(255	)		—		77,325
	$	200,951	$	(387	)	$	52	$	200,616

The amortized cost and fair value of the marketable securities by contractual maturities as of December 31, 2024 are presented below (in thousands):

	Amortized
	Cost		Fair Value
Due in one year or less	$	86,122	$	85,951
Due after one year through five years		23,880		23,855
Due after ten years		3,578		3,578
Total marketable securities	$	113,580	$	113,384

Expected maturities could differ from contractual maturities because the security issuers may have the right to prepay obligations without prepayment penalties.

Unrealized losses from fixed-income securities are primarily attributable to changes in interest rates. The Company does not believe any unrealized losses represent impairments based on the evaluation of the available evidence.