Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Operating activities:
Net (loss) income	$ (12,867)	$ (11,713)	$ 474
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Gain on sale of intellectual property	(175)
Impairment of long-lived assets	35	120
Depreciation and amortization	858	648	522
Change in fair value of earn-out liability	260	95	5
Stock-based compensation	1,922	1,821	895
Deferred income taxes		8,985	(209)
Provision for doubtful accounts		122	62
Changes in operating assets and liabilities:
Accounts receivable	2,162	(865)	(1,007)
Inventories	2,091	(537)	(1,987)
Prepaid expenses and other current assets	(50)	(64)	124
Other long-term assets	(63)	84	57
Accounts payable	(270)	(229)	465
Accrued compensation	113	774	(291)
Accrued expenses	25	478	(36)
Accrued warranty	1,132		134
Deferred revenue	1,137	72	132
Other long-term liabilities	125	65	67
Net cash used in operating activities	(3,565)	(144)	(593)
Investing activities:
Acquisition of property and equipment	(575)	(1,062)	(875)
Proceeds from sale of intellectual property	175
Payment on earn-out liability	(382)	(406)	(423)
Net cash used in investing activities	(782)	(1,468)	(1,298)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	2,263	14,813
Proceeds from stock option exercises	377	709	1,027
Taxes paid related to net share settlements of equity awards	(333)	(99)	(606)
Repurchase of employee share awards			(275)
Repurchase of common stock		(59)	(1,563)
Net cash provided by (used in) financing activities	2,307	15,364	(1,417)
Net (decrease) increase in cash and cash equivalents	(2,040)	13,752	(3,308)
Cash and cash equivalents, beginning of year	23,747	9,995	13,303
Cash and cash equivalents, end of year	21,707	23,747	9,995
Cash paid during the year for:
Income taxes	7	$ 22	$ 27
Supplemental disclosure of non-cash activities:
Transfer of inventory to property and equipment	$ 171