Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018		Dec. 30, 2017
Current assets:
Cash and cash equivalents	$ 127,008		$ 134,286	[1]
Short-term investments	23,865		21,329	[1]
Accounts receivable, net	91,451		71,125	[1]
Inventories	63,136		62,085	[1]
Other current assets	10,986		8,613	[1]
Total current assets	316,446		297,438	[1]
Property, plant and equipment, net	33,537		34,172	[1]
Goodwill	64,765		65,613	[1]
Intangible assets, net	14,499		16,748	[1]
Other assets	6,524		6,486	[1]
	435,771		420,457	[1]
Current liabilities:
Short-term borrowings	3,160		3,108	[1]
Current installments of long-term debt	1,185		1,280	[1]
Accounts payable	41,373		37,556	[1]
Accrued compensation and benefits	16,272		20,178	[1]
Accrued warranty	4,402		4,280	[1]
Deferred profit	1,709	[2]	6,608
Income taxes payable	3,905		2,159	[1]
Other accrued liabilities	14,542		10,098	[1]
Total current liabilities	86,548		85,267	[1]
Accrued retirement benefits	18,581		18,544	[1]
Noncurrent deferred gain on sale of facility	9,504		10,233	[1]
Deferred income taxes	3,138		2,921	[1]
Noncurrent income tax liabilities	6,297		6,270	[1]
Long-term debt	4,094		4,575	[1]
Other accrued liabilities	3,146		3,556	[1]
Stockholders' equity:
Preferred stock, $1 par value; 1,000 shares authorized, none issued				[1]
Common stock, $1 par value; 60,000 shares authorized, 28,883 shares issued and outstanding in 2018 and 28,489 shares in 2017	28,883		28,489	[1]
Paid-in capital	128,248		127,663	[1]
Retained earnings	168,040	[2]	150,726	[1]
Accumulated other comprehensive loss	(20,708)		(17,787)
Total stockholders' equity	304,463		289,091	[1]
	$ 435,771		$ 420,457	[1]

[1] Derived from December 30, 2017 audited financial statements

[2] Balance sheet line items include the cumulative-effect adjustment recorded on December 31, 2017.