CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 01, 2017	Jan. 03, 2016	Dec. 28, 2014
Income Statement [Abstract]
Revenue	$ 11,421	$ 18,956	$ 27,845
Cost of revenue	7,648	11,411	16,796
Gross profit	3,773	7,545	11,049
Operating expenses:
Research and development	12,265	14,144	12,186
Selling, general and administrative	10,310	10,619	11,663
Restructuring costs	0	295	0
Loss from operations	(18,802)	(17,513)	(12,800)
Interest expense	(175)	(82)	(85)
Interest income and other expense, net	(106)	(107)	(126)
Income (loss) before income taxes	(19,083)	(17,702)	(13,011)
Provision for income taxes	65	146	68
Net loss	$ (19,148)	$ (17,848)	$ (13,079)
Net loss per share:
Basic (in dollars per share)	$ (0.29)	$ (0.32)	$ (0.23)
Diluted (in dollars per share)	$ (0.29)	$ (0.32)	$ (0.23)
Weighted average shares:
Basic (in shares)	65,377	56,472	55,401
Diluted (in shares)	65,377	56,472	55,401