Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 2,489,000	$ 313,000
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Purchases of marketable securities	(35,313,000)	(68,444,000)
Proceeds from sale and maturity of marketable securities	34,659,000	65,998,000
Change in fair value of marketable securities	(1,256,000)	2,059,000
Deferred income taxes	(1,657,000)	(485,000)
Depreciation and amortization	418,000	386,000
Provision for doubtful accounts	0	25,000
Stock-based compensation	18,000	17,000
Changes in assets and liabilities:
Accounts receivable	(59,000)	(532,000)
Costs and estimated earnings in excess of billings	455,000	(1,419,000)
Inventories	(325,000)	(2,015,000)
Prepaid expenses & other current assets	(955,000)	322,000
Accounts payable	807,000	1,755,000
Customer deposits	3,003,000	(1,166,000)
Accrued expenses	1,763,000	104,000
Total adjustments	1,558,000	(3,395,000)
Cash flows provided by (used in) operating activities	4,047,000	(3,082,000)
Cash flows from investing activities:
Capital expenditures	(6,000)	(661,000)
Cash flows used in investing activities	(6,000)	(661,000)
Net increase (decrease) in cash and cash equivalents	4,041,000	(3,743,000)
Cash and cash equivalents at:
Beginning of period	10,302,000	8,012,000
End of period	$ 14,343,000	$ 4,269,000