STOCK-BASED COMPENSATION - Schedule of Impact on Results of Operations of Recording Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	$ 1,441	$ 1,584	$ 2,028
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	121	132	109
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	614	658	826
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	706	794	1,064
Restructuring Costs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	$ 0	$ 0	$ 29