DEBT AND LINES OF CREDIT (Details) (USD $)	1 Months Ended	12 Months Ended
	Feb. 28, 2007	Dec. 29, 2012	Dec. 31, 2011	Jan. 01, 2011
Debts and Lines of credit
Total short-term borrowings		$ 5,646,000	$ 19,157,000
Components of interest cost on convertible subordinated notes
Amortization of debt discount		12,000	3,891,000	4,058,000
Japanese revolving lines of credit
Debts and Lines of credit
Total short-term borrowings		5,231,000	5,539,000
Maximum borrowing capacity		12,000,000
Japanese revolving lines of credit | Minimum
Debts and Lines of credit
Interest rate, stated rate (as a percent)		1.18%
Japanese revolving lines of credit | Maximum
Debts and Lines of credit
Interest rate, stated rate (as a percent)		2.475%
Japanese receivables financing facilities
Debts and Lines of credit
Total short-term borrowings		415,000	1,262,000
Interest rate, stated rate (as a percent)		1.475%
Maximum borrowing capacity		6,400,000
Convertible notes
Debts and Lines of credit
Total short-term borrowings			12,356,000
Interest rate, stated rate (as a percent)		2.50%
Amount of debt issued	175,000,000
Components of interest cost on convertible subordinated notes
Contractual interest		39,000	2,941,000	3,196,000
Amortization of debt discount		12,000	3,891,000	4,058,000
Interest cost on convertible subordinated notes		$ 51,000	$ 6,832,000	$ 7,254,000