Investments (Tables)

3 Months Ended

6 Months Ended

Dec. 31, 2021

Mar. 31, 2022

Held To Maturity Securities Classified [Abstract]

Summary of Short-term and Long-term Investments and Marketable Securities

The following tables summarize the Company’s short-term and long-term investments and marketable securities as of March 31, 2022 and September 30, 2021 by measurement category:

	As of March 31, 2022
	(In thousands)
	Cost Basis		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Classified as Cash Equivalents
Commercial notes (due within ninety days)	$	26,678	$	1	$	(1	)	$	26,678
Classified as Held to Maturity
Commercial notes (due within one year)	$	142,912	$	225	$	(307	)	$	142,830
Commercial notes (due within one through three years)	$	201,590	$	-	$	(5,864	)	$	195,726
Certificate of deposit (due within one year)	$	50,000	$	-	$	-		$	50,000
Classified as Marketable Securities
Marketable securities	$	128,805	$	-	$	(6,230	)	$	122,575
Total	$	549,985	$	226	$	(12,402	)	$	537,809
	As of September 30, 2021
	(In thousands)
	Cost Basis		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Classified as Held to Maturity
Commercial notes (due within one year)	$	56,627	$	803	$	-		$	57,430
Commercial notes (due within one through three years)	$	195,595	$	1,151	$	(103	)	$	196,643
Certificate of deposit (due within one through two years)	$	50,000	$	-	$	-		$	50,000
Classified as Marketable Securities
Marketable securities	$	127,481	$	-	$	(753	)	$	126,728
Total	$	429,703	$	1,954	$	(856	)	$	430,801