Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands		Sep. 29, 2018	Sep. 30, 2017
Deferred tax assets [Abstract]
Net operating loss carryforwards	[1]	$ 38,672	$ 59,731
Allowance for doubtful accounts	[1]	225	315
Inventory	[1]	291	572
Deferred revenue	[1]	661	1,041
AMT credit carryforward	[1]	1,086	1,086
Other accruals	[1]	1,661	1,883
Total deferred tax assets	[1]	42,596	64,628
Deferred tax liabilities [Abstract]
Intangible assets		1,131	1,223
Property, plant and equipment		2,498	4,217
Total deferred tax liabilities		3,629	5,440
Net deferred tax assets		38,967	59,188
Valuation allowance	[1]	(37,881)	(59,188)
Net deferred tax assets		$ 1,086	$ 0

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