Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016	Jan. 01, 2017
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase obligations due within next twelve months	$ 956		$ 956
Capital lease maintenance commitment	26		26
Total rent expense, net of sublease income	214	$ 219	635	$ 623
Wafer and finished goods inventory
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Outstanding commitment for purchases	746		746		$ 1,600
Other goods and services
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Total outstanding purchase obligations	$ 982		$ 982