UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017
Cash flows from operating activities:
Net loss	$ (7,454)	$ (7,172)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	675	709
Stock-based compensation	911	665
Write-down of inventories	126	104
Write-off of equipment	5	0
Changes in operating assets and liabilities:
Accounts receivable	(1,266)	(212)
Inventories	(857)	(1,409)
Other assets	(95)	265
Trade payables	263	(846)
Accrued liabilities	172	73
Deferred revenue	0	79
Other long-term liabilities	47	(14)
Net cash used in operating activities	(7,473)	(7,758)
Cash flows from investing activities:
Capital expenditures for property and equipment	(95)	(48)
Net cash used in investing activities	(95)	(48)
Cash flows from financing activities:
Payment of capital lease obligations	(236)	(299)
Proceeds from line of credit	12,000	6,000
Payment of line of credit	(12,000)	(6,000)
Proceeds from issuance of common stock	15,855	17,304
Stock issuance costs	(1,638)	(1,771)
Taxes for net issuance of stock awards	(125)	(64)
Net cash provided by financing activities	13,856	15,170
Net increase in cash and cash equivalents	6,288	7,364
Cash and cash equivalents at beginning of period	16,527	14,870
Cash and cash equivalents at end of period	22,815	22,234
Supplemental schedule of non-cash investing and financing activities :
Capital lease obligation to finance capital expenditures	418	296
Purchase of equipment included in accounts payable	$ 0	$ 208