SUPPLEMENTAL BALANCE SHEET INFORMATION (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 04, 2015	Mar. 29, 2014	Jan. 03, 2015
Accrued Warranty Obligations
Balance at beginning of year	$ 3,556	$ 3,285
Additions charged to cost of sales	811	906
Warranty claims	(808)	(781)
Balance at end of period	3,559	3,410
Accrued Expenses and Other Current Liabilities
Deferred revenue	12,454		13,032
Deferred lease liability	4,981		5,094
Accrued income taxes	3,631		2,219
Short-term accrued warranty obligations	3,315		3,324
Other	9,846		8,128
Accrued expenses and other current liabilities, total	34,227		31,797
Accumulated Other Comprehensive Loss
Cumulative foreign currency translation losses	(20,767)		(14,556)
Unrecognized net pension losses, net of tax	(4,385)		(4,855)
Unrealized gains on investment and marketable securities, net of tax	1,321		1,429
Accumulated other comprehensive loss	$ (23,831)		$ (17,982)