Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Condensed Consolidated Statements of Operations [Abstract]
Net revenue	$ 18,690,000	$ 22,986,000	$ 41,375,000	$ 49,189,000
Costs and expenses:
Production costs	13,720,000	17,237,000	31,662,000	38,651,000
Product engineering and development	420,000	670,000	1,322,000	1,764,000
Selling, general and administrative	1,867,000	2,678,000	5,810,000	6,999,000
Total operating expenses	16,007,000	20,585,000	38,794,000	47,414,000
Operating income	2,683,000	2,401,000	2,581,000	1,775,000
Other income (expense):
Interest and dividend income, net of fees	516,000	581,000	1,759,000	1,704,000
Net realized and unrealized gain (loss) on marketable securities	145,000	(1,290,000)	888,000	3,548,000
Other	18,000	13,000	33,000	49,000
Other income (expense) total	679,000	(696,000)	2,680,000	5,301,000
Income before income tax expense	3,362,000	1,705,000	5,261,000	7,076,000
Income tax expense	873,000	513,000	771,000	2,243,000
Net Income	$ 2,489,000	$ 1,192,000	$ 4,490,000	$ 4,833,000
Basic Income per Common Share:
Net income per share	$ 0.26	$ 0.13	$ 0.47	$ 0.51
Diluted Income per Common Share:
Net income per share	$ 0.26	$ 0.13	$ 0.47	$ 0.51