CONDENSED UNAUDITED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2016	Jun. 28, 2015	Jul. 03, 2016	Jun. 28, 2015
Income Statement [Abstract]
Revenue	$ 2,717	$ 4,973	$ 5,667	$ 11,132
Cost of revenue	1,941	2,830	3,735	6,110
Gross profit	776	2,143	1,932	5,022
Operating expenses:
Research and development	3,683	3,493	7,130	6,970
Selling, general and administrative	2,591	2,690	5,284	5,650
Restructuring costs	0	169	0	169
Total operating expenses	6,274	6,352	12,414	12,789
Loss from operations	(5,498)	(4,209)	(10,482)	(7,767)
Interest expense	(34)	(15)	(72)	(29)
Interest income and other expense, net	(15)	(33)	(22)	(59)
Loss before income taxes	(5,547)	(4,257)	(10,576)	(7,855)
Provision for income taxes	27	21	91	61
Net loss	$ (5,574)	$ (4,278)	$ (10,667)	$ (7,916)
Net loss per share:
Basic (in dollars per share)	$ (0.08)	$ (0.08)	$ (0.17)	$ (0.14)
Diluted (in dollars per share)	$ (0.08)	$ (0.08)	$ (0.17)	$ (0.14)
Weighted average shares:
Basic (in shares)	67,415	56,359	62,893	56,275
Diluted (in shares)	67,415	56,359	62,893	56,275