Note 10 - Discontinued Operations - Balance Sheet Information and Operating Results for Fixture Services Business (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018	Dec. 29, 2018
Assets:
Total current assets	$ 4,100		$ 4,100		$ 3,741	[1]
Total assets	4,165		4,165		3,820
Liabilities:
Total current liabilities	624		624		518	[1]
Income, net of tax	24		188
Xcerra [Member]
Liabilities:
Net sales	1,708		3,300
Operating income before income taxes	38		227
Income tax provision	14		39
Income, net of tax	24		188
Xcerra [Member] | Discontinued Operations, Held-for-sale [Member]
Assets:
Cash and cash equivalents	750		750		461
Accounts receivable, net	1,856		1,856		1,718
Inventories	1,432		1,432		1,388
Other current assets	62		62		174
Total current assets	4,100		4,100		3,741
Property, plant and equipment, net	52		52		66
Other noncurrent assets	13		13		13
Total assets	4,165		4,165		3,820
Liabilities:
Other accrued current liabilities	624		624		518
Total current liabilities	624		624		518
Noncurrent liabilities
Total liabilities	$ 624		$ 624		$ 518

[1] Derived from December 29, 2018 audited financial statements