Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 28, 2019	Sep. 29, 2018	[1]
Deferred tax assets [Abstract]
Net operating loss carryforwards	$ 38,914	$ 38,672
Allowance for doubtful accounts	170	225
Inventory	231	291
Deferred revenue	615	661
AMT credit carryforward	513	1,086
Other accruals	1,416	1,661
Total deferred tax assets	41,859	42,596
Deferred tax liabilities [Abstract]
Intangible assets	1,205	1,131
Property, plant and equipment	2,145	2,498
Total deferred tax liabilities	3,350	3,629
Net deferred tax assets	38,509	38,967
Valuation allowance	(37,996)	(37,881)
Net deferred tax assets	$ 513	$ 1,086

[1] As described above, federal net deferred tax assets of the Corporate Entities were remeasured, pursuant to the 2017 Act, using the new 21% federal income tax rate and the full valuation allowance was adjusted accordingly.