Segment Data and Related Information - Statement of Operations Data (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Operating (loss) income	$ (8,488)	$ (3,131)	$ (5,249)	$ (2,240)	$ (7,128)	$ (7,669)	$ 12,171	$ 2,846	$ (19,108)	$ 220	$ (35,625)
Fiber Optics
Segment Reporting Information [Line Items]
Operating (loss) income									(25,400)	(8,382)	(26,684)
Photovoltaics
Segment Reporting Information [Line Items]
Operating (loss) income									$ 6,292	$ 8,602	$ (8,941)