Stock-Based Compensation - Schedule of Allocation of Recognized Period Cost (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	$ 479,000	$ 347,000	$ 911,000	$ 665,000
Stock-based compensation, capitalized costs	0	0	0	0
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	35,000	20,000	69,000	53,000
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	207,000	134,000	390,000	273,000
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total costs and expenses	$ 237,000	$ 193,000	$ 452,000	$ 339,000