Note 15 - Financial Instruments and Fair Value Measurements (Details) - Estimated Fair Value of Financial Instruments, Current Year (USD $) In Thousands, unless otherwise specified	Sep. 28, 2014	Dec. 29, 2013
Short-Term Investments
Available for Sale Securities	$ 47,327	$ 49,099
Commercial Paper, Not Included with Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Short-Term Investments
Available for Sale Securities	33,969	21,993
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Short-Term Investments
Available for Sale Securities	33,969	21,993
Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Short-Term Investments
Available for Sale Securities	13,118	27,106
Corporate Bond Securities [Member]
Short-Term Investments
Available for Sale Securities	13,118	27,106
Certificates of Deposit [Member] | Fair Value, Inputs, Level 1 [Member]
Short-Term Investments
Available for Sale Securities	240
Certificates of Deposit [Member]
Short-Term Investments
Available for Sale Securities	$ 240