Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operations:
Net income	$ 5,319,000	$ 354,000
Adjustments to reconcile net income to cash (used in) provided by operating activities:
Purchases of marketable securities	(335,848,000)	(318,647,000)
Proceeds from sale and maturity of marketable securities	334,844,000	317,965,000
Change in fair value of marketable securities	(251,000)	319,000
Deferred income taxes	796,000	(543,000)
Depreciation and amortization	1,050,000	1,008,000
Net losses on disposal of property and equipment		1,000
Provision for doubtful accounts	55,000	35,000
Stock-based compensation	25,000	190,000
Changes in assets and liabilities:
Accounts receivable	(680,000)	164,000
Costs and estimated earnings in excess of billings	(7,341,000)	(182,000)
Inventories	1,213,000	586,000
Prepaid expenses and other current assets	306,000	456,000
Accounts payable	(336,000)	339,000
Customer deposits	(810,000)	1,187,000
Accrued expenses and other current liabilities	1,388,000	(299,000)
Total adjustments	(5,589,000)	2,579,000
Cash flows (used in) provided by operating activities	(270,000)	2,933,000
Cash flows used in investing activities:
Capital expenditures	(158,000)	(587,000)
Cash flows used in investing activities	(158,000)	(587,000)
Cash flows from financing activities:
Proceeds from stock option exercises	164,000	29,000
Cash flows provided by financing activities	164,000	29,000
Net increase (decrease) in cash	(264,000)	2,375,000
Cash at:
Beginning of period	11,152,000	7,193,000
End of period	$ 10,888,000	$ 9,568,000