Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operations:
Net income	$ 2,001,000	$ 3,641,000
Adjustments to reconcile net income to cash provided by operating activities:
Purchases of marketable securities	(27,606,000)	(22,965,000)
Proceeds from sale and maturity of marketable securities	28,264,000	23,339,000
Change in fair value of marketable securities	(644,000)	(4,835,000)
Deferred income taxes	648,000	1,699,000
Depreciation and amortization	578,000	514,000
Provision for doubtful accounts	40,000	240,000
Stock-based compensation	124,000	92,000
Change in assets and liabilities:
Accounts receivable	(122,000)	(202,000)
Costs and estimated earnings in excess of billings	(121,000)	4,071,000
Inventories	(1,597,000)	(1,779,000)
Prepaid expenses and other current assets	(948,000)	367,000
Accounts payable	384,000	791,000
Customer deposits	2,713,000	7,380,000
Accrued expenses and other	(40,000)	164,000
Total adjustments	1,673,000	8,876,000
Cash flows provided by operating activities	3,674,000	12,517,000
Cash flows used in investing activities:
Capital expenditures	(637,000)	(730,000)
Cash flows used in investing activities	(637,000)	(730,000)
Net increase in cash	3,037,000	11,787,000
Cash at:
Beginning of period	3,361,000	1,715,000
End of period	$ 6,398,000	$ 13,502,000