CONDENSED UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2017	Jul. 03, 2016	Jul. 02, 2017	Jul. 03, 2016
Income Statement [Abstract]
Revenue	$ 3,026	$ 2,717	$ 6,196	$ 5,667
Cost of revenue	1,646	1,941	3,443	3,735
Gross profit	1,380	776	2,753	1,932
Operating expenses:
Research and development	2,319	3,683	4,746	7,130
Selling, general and administrative	2,614	2,591	5,028	5,284
Total operating expenses	4,933	6,274	9,774	12,414
Loss from operations	(3,553)	(5,498)	(7,021)	(10,482)
Interest expense	(21)	(34)	(82)	(72)
Interest income and other (expense), net	1	(15)	1	(22)
Loss before income taxes	(3,573)	(5,547)	(7,102)	(10,576)
Provision for income taxes	34	27	70	91
Net loss	$ (3,607)	$ (5,574)	$ (7,172)	$ (10,667)
Net loss per share:
Basic (in dollars per share)	$ (0.05)	$ (0.08)	$ (0.10)	$ (0.17)
Diluted (in dollars per share)	$ (0.05)	$ (0.08)	$ (0.10)	$ (0.17)
Weighted average shares:
Basic (in shares)	79,799	67,415	74,327	62,893
Diluted (in shares)	79,799	67,415	74,327	62,893