Note 10 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jan. 03, 2021	Jan. 03, 2020	Dec. 29, 2019
Net operating losses	$ 43,703		$ 40,717
Accruals and reserves	1,239		1,345
Credits carryforward	5,860		5,765
Depreciation and amortization	9,240		9,760
Stock-based compensation	485		637
Operating lease liability	469		529
Gross deferred tax assets	60,996		58,753
Right-of-use asset	(458)		(552)
Gross deferred tax assets	(458)		(552)
Net deferred tax assets	60,538		58,201
Valuation allowance	(60,486)	$ (60,000)	(58,140)
Total deferred tax asset	$ 52		$ 61