Income Taxes - Operating Loss and Tax Credit Carryforwards (Details) $ in Millions	Dec. 28, 2019 USD ($)
Federal | Research and development tax credit
Operating loss and tax credit carryforwards
Tax credit carryforwards	$ 3.3
State
Operating loss and tax credit carryforwards
Operating loss carryforwards	33.1
State | Tentative minimum tax credit
Operating loss and tax credit carryforwards
Tax credit carryforwards	0.1
State | Research and development tax credit
Operating loss and tax credit carryforwards
Tax credit carryforwards	12.6
Silicon Clocks, Spectra Linear and Ember | Federal
Operating loss and tax credit carryforwards
Operating loss carryforwards	27.9
Silicon Clocks, Spectra Linear and Ember | Federal | Research and development tax credit
Operating loss and tax credit carryforwards
Tax credit carryforwards	$ 1.9