Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jan. 01, 2021	Jan. 03, 2020
Deferred tax assets:
Allowance for doubtful accounts and sales returns	$ 357	$ 233
Inventories	691	703
Accrued vacation	599	428
Accrued other expenses	786	1,036
Stock-based compensation	3,277	2,859
Pensions	1,679	1,159
Depreciation and amortization		162
Net operating loss carryforwards	38,642	32,251
Business, foreign, AMT and R&D credit carryforwards	3,051	3,164
Prepaid expenses	280	272
Capitalized R&D	1,000	986
Operating lease liability	1,687	1,309
Other	19	5
Valuation allowance	(42,502)	(37,007)
Total deferred tax assets	9,566	7,560
Deferred tax liabilities:
Foreign tax withholding	(1,295)	(1,295)
Operating lease ROU assets	(1,662)	(1,309)
Depreciation and amortization	(424)
Amortization of R&D	(846)	(805)
Net foreign earnings not permanently reinvested	(617)	(401)
Total deferred tax liabilities	(4,844)	(3,810)
Total net deferred tax assets	$ 4,722	$ 3,750