Note 4. Short-Term Investments (Details) - Short-Term Investments (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 30, 2014	Dec. 29, 2013
Note 4. Short-Term Investments (Details) - Short-Term Investments [Line Items]
Amortized Cost	$ 48,419	$ 49,099
Fair Value	48,405	49,099
Unrealized Gain (Loss)	(14)	0
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
Note 4. Short-Term Investments (Details) - Short-Term Investments [Line Items]
Amortized Cost	29,946	21,986
Fair Value	29,943	21,993
Unrealized Gain (Loss)	(3)	7
Corporate Bond Securities [Member]
Note 4. Short-Term Investments (Details) - Short-Term Investments [Line Items]
Amortized Cost	15,873	27,113
Fair Value	15,864	27,106
Unrealized Gain (Loss)	(9)	(7)
Certificates of Deposit [Member]
Note 4. Short-Term Investments (Details) - Short-Term Investments [Line Items]
Amortized Cost	2,600
Fair Value	2,598
Unrealized Gain (Loss)	$ (2)