Income and Other Taxes (Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Federal net operating loss carryforwards	$ 91,639	$ 144,455
Foreign net operating loss carryforwards	1,301	587
Income tax credit carryforwards	2,671	3,211
Inventory reserves	2,065	2,037
Accounts receivable reserves	123	8
Accrued warranty reserve	144	249
State net operating loss carryforwards	4,624	4,525
Stock compensation	728	2,367
Deferred compensation	200	349
Fixed assets and intangibles	(33)	136
Other	838	927
Total deferred tax assets	104,300	158,851
Valuation allowance	(104,300)	(158,851)
Net deferred tax assets	$ 0	$ 0