INCOME TAXES - Schedule of U.S. and Foreign Components of Consolidated Income (Loss) before Income Taxes and Provision for (Benefit from) Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2018	Dec. 31, 2017	Jan. 01, 2017
Income (loss) before income taxes:
U.S.	$ (13,982)	$ (14,253)	$ (19,340)
Foreign	355	209	257
Loss before income taxes	(13,627)	(14,044)	(19,083)
Current:
Federal	(19)	0
State	2	2	(3)
Foreign	169	85	75
Subtotal	152	87	72
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	0	0	(7)
Subtotal	0	0	(7)
Provision for income taxes	$ 152	$ 87	$ 65