Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Net unrealized gains (losses)	$ 4,316,000	$ (6,864,000)
Transfers of investments between Level 1 and Level 2	0	0
Impairment loss recognized on an asset group	0	0
Valuation allowance	0	0
Costs and estimated earnings in excess of billings	1,508,000	2,118,000
Net revenue	105,075,000	103,479,000
Accounts receivable related to contracts with customers	114,000	142,000
Total long-term assets	16,794,000	16,834,000
Fair Value Measurement Asset Transfers Net	$ 10,000,000
Maximum [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Contract assets collection period	1 year
Current Liabilities [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Customer deposits related to contracts with customers	$ 6,815,000	$ 5,864,000
Revenue [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Number of customers	0	0
Entities Owned by One Global Company [Member] | Revenue [Member] | Customer One [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration	14.80%
Entities Owned by One Global Company [Member] | Revenue [Member] | No Customer [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration	10.00%	10.00%
Three to Four Years Old Inventory [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Inventory, minimum time period on the shelf, years	3 years
Inventory, maximum time period on the shelf, years	4 years
Cost basis reduction in inventory, percentage	50.00%
Four to Five Years Old Inventory [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Inventory, minimum time period on the shelf, years	4 years
Inventory, maximum time period on the shelf, years	5 years
Cost basis reduction in inventory, percentage	75.00%
Greater Than Five Years Old Inventory [Member]
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items]
Inventory, minimum time period on the shelf, years	5 years
Inventory valuation estimate	$ 0