Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operations:
Net income	$ 354,000	$ 4,010,000
Adjustments to reconcile net income to cash provided by operating activities:
Purchases of marketable securities	(318,647,000)	(220,103,000)
Proceeds from sale and maturity of marketable securities	317,965,000	218,082,000
Change in fair value of marketable securities	319,000	(2,458,000)
Deferred income taxes	(543,000)	867,000
Depreciation and amortization	1,008,000	1,029,000
Net (gains) losses on disposal of property and equipment	1,000	(417,000)
Provision for doubtful accounts	35,000	40,000
Stock-based compensation	190,000	199,000
Changes in assets and liabilities:
Accounts receivable	164,000	11,000
Costs and estimated earnings in excess of billings	(182,000)	(411,000)
Inventories	586,000	1,511,000
Prepaid expenses and other current assets	456,000	170,000
Accounts payable	339,000	(238,000)
Customer deposits	1,187,000	(1,613,000)
Accrued expenses and other	(299,000)	(583,000)
Total adjustments	2,579,000	(3,914,000)
Cash flows provided by operating activities	2,933,000	96,000
Cash flows provided by (used in) investing activities:
Capital expenditures	(587,000)	(601,000)
Proceeds from sale of property and equipment		685,000
Cash flows provided by (used in) investing activities	(587,000)	84,000
Cash flows from financing activities:
Proceeds from stock option exercises	29,000
Cash flows provided by financing activities	29,000
Net increase in cash	2,375,000	180,000
Cash at:
Beginning of period	7,193,000	9,557,000
End of period	$ 9,568,000	$ 9,737,000