Income Taxes - Operating Loss and Tax Credit Carryforwards (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Jan. 02, 2016
Operating loss and tax credit carryforwards
Deferred tax asset	$ 88,470	$ 88,366
Deferred tax liability	62,958	$ 64,855
Federal
Operating loss and tax credit carryforwards
Research and development tax credit carryforwards	7,400
State
Operating loss and tax credit carryforwards
Operating loss carryforwards	49,100
Research and development tax credit carryforwards	13,100
Silicon Clocks, Spectra Linear and Ember | Federal
Operating loss and tax credit carryforwards
Operating loss carryforwards	44,500
Research and development tax credit carryforwards	1,900
Energy Micro | Foreign
Operating loss and tax credit carryforwards
Operating loss carryforwards	$ 13,200