Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 01, 2018	Apr. 02, 2017	Dec. 31, 2017
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase obligations due within next twelve months	$ 1,500
Capital lease maintenance commitment	62
Total rent expense, net of sublease income	238	$ 211
Wafer and finished goods inventory
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Outstanding commitment for purchases	946		$ 1,100
Other goods and services
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Total outstanding purchase obligations	$ 1,600