Balance Sheet Components (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 30, 2018
Inventories:
Raw Material	$ 191
Work-in-process	2,606	$ 3,120
Finished goods	774	716
Inventories	3,571	3,836
Other current assets:
Prepaid expenses	1,497	1,483
Other	287	292
Other current assets	1,784	1,775
Property and equipment:
Property and equipment, gross	13,295	14,149
Less: Accumulated depreciation and amortization	(12,422)	(12,700)
Property and equipment, net	873	1,449
Accrued liabilities:
Employee related accruals	1,131	1,154
Other	589	749
Accrued liabilities	1,720	1,903
Equipment
Property and equipment:
Property and equipment, gross	10,714	10,607
Software
Property and equipment:
Property and equipment, gross	1,823	2,788
Furniture and fixtures
Property and equipment:
Property and equipment, gross	42	42
Leasehold improvements
Property and equipment:
Property and equipment, gross	$ 716	$ 712