BALANCE SHEET COMPONENTS - Schedule of Balance Sheet Components (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Jan. 01, 2017
Inventories:
Work-in-process	$ 2,894	$ 1,538
Finished goods	665	479
Inventories	3,559	2,017
Other current assets:
Prepaid expenses	836	960
Other	161	163
Other current assets	997	1,123
Property and equipment:
Property and equipment, gross	14,855	14,897
Accumulated depreciation and amortization	(12,480)	(12,132)
Property and equipment, net	2,375	2,765
Accrued liabilities:
Employee compensation related accruals	1,143	1,222
Other	510	358
Accrued liabilities	1,653	1,580
Equipment
Property and equipment:
Property and equipment, gross	10,996	11,524
Software
Property and equipment:
Property and equipment, gross	3,139	2,624
Furniture and fixtures
Property and equipment:
Property and equipment, gross	46	41
Leasehold improvements
Property and equipment:
Property and equipment, gross	$ 674	$ 708