CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Jan. 01, 2017
Income Statement [Abstract]
Revenue	$ 12,629	$ 12,149	$ 11,421
Cost of revenue	6,295	6,627	7,648
Gross profit	6,334	5,522	3,773
Operating expenses:
Research and development	9,948	9,572	12,265
Selling, general and administrative	9,982	9,900	10,310
Loss from operations	(13,596)	(13,950)	(18,802)
Interest expense	(108)	(115)	(175)
Interest income and other expense, net	77	21	(106)
Loss before income taxes	(13,627)	(14,044)	(19,083)
Provision for income taxes	152	87	65
Net loss	$ (13,779)	$ (14,131)	$ (19,148)
Net loss per share:
Basic and diluted	$ (0.15)	$ (0.18)	$ (0.29)
Weighted average shares:
Basic and diluted	89,110	77,291	65,377