Consolidated Statements of Cash Flows - USD ($)		12 Months Ended
		Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income		$ 10,196,000	$ 12,694,000	[1]
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Purchase of marketable securities		(188,066,000)	(256,124,000)	[1]
Proceeds from sale and maturity of marketable securities		188,047,000	239,462,000	[1]
Change in value of marketable securities		(1,245,000)	490,000	[1]
Deferred income taxes		732,000	262,000	[1]
Depreciation and amortization		1,600,000	1,380,000	[1]
Provision for doubtful accounts		175,000	210,000	[1]
Loss on sale of fixed assets		4,000	3,000
Stock-based compensation		71,000	71,000	[1]
Changes in assets and liabilities:
Accounts receivable		(785,000)	(19,000)	[1]
Costs and estimated earnings in excess of billings		(1,938,000)	(5,132,000)	[1]
Inventories		(3,476,000)	(1,702,000)	[1]
Prepaid expenses		849,000	312,000	[1]
Accounts payable		69,000	518,000	[1]
Customer deposits		(2,645,000)	(4,065,000)	[1]
Accrued expenses		575,000	(357,000)	[1]
Total adjustments		(6,033,000)	(24,691,000)	[1]
Cash flows provided by (used in) operating activities		4,163,000	(11,997,000)	[1]
Cash flows from investing activities:
Capital expenditures		(2,104,000)	(3,550,000)	[1]
Cash flows used in investing activities		(2,104,000)	(3,550,000)	[1]
Cash flows from financing activities:
Proceeds from stock option exercises		231,000	626,000	[1]
Cash flows provided by financing activities		231,000	626,000	[1]
Net increase (decrease) in cash and cash equivalents		2,290,000	(14,921,000)	[1]
Cash and cash equivalents at:
Beginning of year	[1]	8,012,000	22,933,000
End of year		$ 10,302,000	$ 8,012,000	[1]

[1] The amounts for the year ended September 30, 2018 have been adjusted to reflect the change in inventory accounting method, as described in Notes 1 and 2 to the Consolidated Financial Statements.