Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Operating activities:
Net loss	$ (8,813)	$ (12,813)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on disposal of property and equipment	2	4
Depreciation and amortization	688	809
Change in fair value of earn-out liability	47	149
Stock-based compensation	1,703	1,803
Provision for doubtful accounts	25
Changes in operating assets and liabilities:
Accounts receivable	(271)	(1,159)
Inventories	545	463
Prepaid expenses and other current assets	145	(54)
Operating lease right-of-use assets	1,219
Other long-term assets	47	(49)
Accounts payable	76	788
Accrued compensation	(563)	503
Accrued expenses	(752)	614
Accrued warranty	(324)	(875)
Deferred revenue	(415)	(295)
Operating lease liabilities	(1,274)
Other long-term liabilities	2	87
Net cash used in operating activities	(7,913)	(10,025)
Investing activities:
Acquisition of property and equipment	(128)	(440)
Payment on earn-out liability	(381)	(387)
Net cash used in investing activities	(509)	(827)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs		10,475
Proceeds from stock option exercises		98
Taxes paid related to net share settlements of equity awards	(156)	(194)
Net cash (used in) provided by financing activities	(156)	10,379
Effect of foreign exchange rate changes	37	(40)
Net decrease in cash and cash equivalents	(8,541)	(513)
Cash and cash equivalents, beginning of year	21,194	21,707
Cash and cash equivalents, end of year	12,653	21,194
Supplemental disclosure of cash flow information:
Cash paid during the year for Income taxes	14	13
Supplemental disclosure of non-cash activities:
Transfer of inventory to property and equipment	$ 67	$ 166