Income and Other Taxes (Narrative) (Details) - USD ($)		3 Months Ended								12 Months Ended
	Jan. 01, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Operating Loss Carryforwards [Line Items]
Income tax benefit (expense)		$ (53,000)	$ 0	$ 169,000	$ 333,000	$ (32,000)	$ (19,000)	$ 8,000	$ (120,000)	$ 449,000	$ (163,000)	$ (14,000)
Income tax benefit, discontinued operations										$ 0	$ 0	$ 24,000
Effective tax rate										(2.50%)	1.90%	0.50%
Tax Cuts and Jobs Act, decrease in net deferred tax assets	$ 58,000,000	58,000,000
Tax Cuts and Jobs Act, tax expense										$ 500,000
Adjustments based on tax positions related to the current year										0	$ 131,000
Decrease in unrecognized tax benefits												$ 100,000
Income tax penalties and interest accrued		400,000				$ 300,000				400,000	$ 300,000
Operating loss carryforward portion subject limitation		219,500,000								219,500,000
Operating loss carryforward portion not subject to limitation		216,900,000								216,900,000
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		436,400,000								436,400,000
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		5,200,000								5,200,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		53,000,000								53,000,000
Continuing Operations
Operating Loss Carryforwards [Line Items]
Decrease in unrecognized tax benefits												112,800
Discontinued Operations
Operating Loss Carryforwards [Line Items]
Decrease in unrecognized tax benefits												12,000
Income tax credits and adjustments												$ 400,000
Foreign Income and Research And Development Credit
Operating Loss Carryforwards [Line Items]
Tax credit carryforward		$ 2,700,000								$ 2,700,000