CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Statement of Financial Position [Abstract]
Net of allowances of trade, note and other accounts receivable	$ 0	$ 0
Net of amortization of intangible assets	$ 8,113	$ 7,498
Undesignated preferred stock, par value	$ 0.001	$ 0.001
Undesignated preferred stock, shares authorized	10,000,000	10,000,000
Undesignated preferred stock, shares issued	0	0
Undesignated preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	23,346,000	23,346,000
Common stock, shares outstanding	22,700,000	22,700,000
Treasury stock, shares	4,989,000	4,965,000