Discontinued Operations (Income Statements) (Details) - Discontinued Operations, Disposed of by Sale - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Photovoltaics Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	$ 0	$ 0	$ 0
Cost of revenue	0	12	(159)
Gross profit	0	(12)	159
Operating expense (income)	0	13	(868)
Income from discontinued operations before income tax expense	0	(25)	1,027
Income tax benefit (expense)	0	0	20
Income from discontinued operations, net of tax	0	(25)	1,047
Digital Products Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	0	0	0
Cost of revenue	0	0	(500)
Gross profit	0	0	500
Operating expense (income)	0	2	(292)
Recognition of previously deferred gain on sale of assets	0	0	3,804
Other income	0	41	0
Income from discontinued operations before income tax expense	0	39	4,596
Income tax benefit (expense)	0	0	4
Income from discontinued operations, net of tax	$ 0	$ 39	$ 4,600