Intangible Assets (Schedule by Reporting Segment) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Sep. 30, 2012
Finite-Lived Intangible Assets [Line Items]
Gross Assets	$ 22,907	$ 22,907
Accumulated Amortization	(20,114)	(19,479)
Total	2,793	3,428
Estimated Future Amortization Expense
Six months ended September 30, 2013	634
Fiscal year ended September 30, 2014	1,017
Fiscal year ended September 30, 2015	555
Fiscal year ended September 30, 2016	555
Fiscal year ended September 30, 2017	32
Thereafter	0
Total	2,793	3,428
Fiber Optics
Finite-Lived Intangible Assets [Line Items]
Gross Assets	20,935	20,935
Accumulated Amortization	(18,429)	(17,890)
Total	2,506	3,045
Estimated Future Amortization Expense
Total	2,506	3,045
Fiber Optics | Core Technology
Finite-Lived Intangible Assets [Line Items]
Gross Assets	12,727	12,727
Accumulated Amortization	(11,486)	(11,150)
Total	1,241	1,577
Estimated Future Amortization Expense
Total	1,241	1,577
Fiber Optics | Customer Relations
Finite-Lived Intangible Assets [Line Items]
Gross Assets	3,511	3,511
Accumulated Amortization	(2,503)	(2,359)
Total	1,008	1,152
Estimated Future Amortization Expense
Total	1,008	1,152
Fiber Optics | Patents
Finite-Lived Intangible Assets [Line Items]
Gross Assets	4,697	4,697
Accumulated Amortization	(4,440)	(4,381)
Total	257	316
Estimated Future Amortization Expense
Total	257	316
Photovoltaics | Patents
Finite-Lived Intangible Assets [Line Items]
Gross Assets	1,972	1,972
Accumulated Amortization	(1,685)	(1,589)
Total	287	383
Estimated Future Amortization Expense
Total	$ 287	$ 383