CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Operating activities
Net loss	$ 1,148,000	$ 3,581,000
Adjustments to reconcile net income to net cash and cash equivalents provided by (used in) operating activities:
Depreciation & amortization	2,976,000	3,999,000
Net amortization (accretion) of investment premiums and discounts	(75,000)	(97,000)
Amortization of intangible assets	615,000	615,000
Equity-based compensation	3,225,000	3,307,000
Straight-line rent adjustment and amortization of lease incentives	(289,000)	(31,000)
Change in the fair value of acquisition-related contingent consideration	7,000	(139,000)
Deferred income taxes	1,661,000	(7,909,000)
Loss on disposal of equipment	120,000	442,000
Changes in assets and liabilities:
Accounts receivable	(902,000)	(7,243,000)
Inventories	6,301,000	3,278,000
Prepaid expenses and other assets	1,621,000	(141,000)
Accounts payable	(1,850,000)	2,104,000
Accrued payroll and other accrued liabilities	694,000	(6,770,000)
Customer advances	(10,307,000)	3,288,000
Total adjustments	3,797,000	(5,297,000)
Net cash and cash equivalents provided by (used in) operating activities	4,945,000	(1,716,000)
Investing activities
Purchase of investments	(23,306,000)	(27,353,000)
Proceeds from sales and maturities of investments	21,642,000	29,567,000
Purchase of leasehold improvements and equipment	(4,107,000)	(3,244,000)
Net cash and cash equivalents used in investing activities	(5,771,000)	(1,030,000)
Financing activities
Proceeds from issuance of common stock	2,265,000	3,208,000
Common stock repurchases	(111,000)	(558,000)
Taxes paid related to net share settlement	(404,000)	(831,000)
Payment of acquisition-related contingent consideration	(230,000)
Net cash and cash equivalents provided by financing activities	1,520,000	1,819,000
Effect of exchange rate changes on cash	(24,000)	(130,000)
Net increase (decrease) in cash, cash equivalents and restricted cash	670,000	(1,057,000)
Cash, cash equivalents and restricted cash at beginning of period	19,884,000	20,941,000
Cash, cash equivalents and restricted cash at end of period	20,554,000	19,884,000
Cash paid (received) for:
Income taxes	1,016,000	$ 991,000
Income tax refund	$ (157,000)