Note 10 - Stock-Based Compensation Plans - Share-based Payment Award Stock Options Valuation Assumptions (Details)	12 Months Ended
	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Expected volatility, minimum			39.87%
Risk-free interest rate, minimum			2.29%
Expected term (years), minimum (Year)		6 years	4 years 29 days
Weighted average expected volatility		31.60%
Weighted average expected volatility		31.60%
Weighted average risk-free interest rate		2.51%
Weighted average risk-free interest rate		2.51%
Expected term (in months) (Year)		6 years	4 years 29 days
Employee Stock Purchase Plan [Member]
Expected term (years), minimum (Year)	6 years
Weighted average expected volatility	48.20%
Weighted average expected volatility	48.20%
Weighted average risk-free interest rate	0.89%
Weighted average risk-free interest rate	0.89%
Expected term (in months) (Year)	6 years