CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Jan. 01, 2022	Jan. 02, 2021
Operating activities
Net income	$ 26,620,000	$ 1,056,000
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Depreciation and amortization	3,456,000	3,206,000
Net amortization (accretion) of investment premiums and discounts	109,000	12,000
Amortization of intangible assets	0	274,000
Gain on sale of Photonics division	(54,341,000)
Asset impairment charges	1,246,000
Equity-based compensation	4,003,000	3,389,000
Straight-line rent adjustment and amortization of lease incentives	(463,000)	(286,000)
Deferred income taxes	25,000	917,000
Changes in assets and liabilities:
Accounts receivable	10,850,000	(27,000)
Inventories	9,597,000	3,218,000
Prepaid expenses and other assets	6,000	(462,000)
Accounts payable	(932,000)	60,000
Accrued payroll and other accrued liabilities	(1,972,000)	1,467,000
Customer advances	2,074,000	(3,974,000)
Total adjustments	(26,342,000)	7,794,000
Net cash and cash equivalents provided by operating activities	278,000	8,850,000
Investing activities
Purchase of investments	(17,148,000)	(23,342,000)
Proceeds from sales and maturities of investments	19,550,000	25,355,000
Proceeds from sale of Photonics division	70,000,000
Purchase of leasehold improvements and equipment	(1,198,000)	(2,612,000)
Net cash and cash equivalents provided by (used in) investing activities	71,204,000	(599,000)
Financing activities
Proceeds from issuance of common stock	2,632,000	1,897,000
Common stock repurchases	0	(393,000)
Taxes paid related to net share settlement	(734,000)	(402,000)
Net cash and cash equivalents provided by financing activities	1,898,000	1,102,000
Effect of exchange rate changes on cash	6,000	221,000
Net increase in cash, cash equivalents and restricted cash	73,386,000	9,574,000
Cash, cash equivalents and restricted cash at beginning of period	30,128,000	20,554,000
Cash, cash equivalents and restricted cash at end of period	103,514,000	30,128,000
Cash paid (received) for:
Income taxes	559,000	850,000
Income tax refund	$ (18,000)	$ (157,000)