Note 10 - Income Taxes (Details Textual) - USD ($) $ in Thousands	Jan. 02, 2022	Jan. 03, 2021	Jan. 01, 2018	Dec. 31, 2017
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 2,100	$ 0
Paycheck Protection Program [Member]
Debt Instrument, Face Amount		$ 1,200
Federal [Member]
Operating Loss Carryforwards, Total	183,900		$ 55,300	$ 128,600
Federal [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	3,700
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	94,400
Tax Credit Carryforward, Amount	4,700
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Tax Credit Carryforward, Amount	$ 4,700