Income and Other Taxes (Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Federal net operating loss carryforwards	$ 100,363	$ 99,298
Foreign net operating loss carryforwards	1,680	1,271
Income tax credit carryforwards	2,671	2,671
Inventory reserves	2,320	3,535
Accounts receivable reserves	55	50
Accrued warranty reserve	193	153
State net operating loss carryforwards	5,970	6,174
Stock compensation	806	704
Deferred compensation	443	404
Fixed assets and intangibles	(348)	(2,693)
ROU lease liability	3,529
ROU lease assets	(3,467)
Other	1,322	2,255
Total deferred tax assets	115,537	113,822
Valuation allowance	$ (115,537)	(113,891)
Net deferred tax liabilities		$ (69)