Note 4 - Earnings Per Share (Details Textual) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 29, 2019	Sep. 30, 2020	Sep. 29, 2019
Dilutive Securities Included in Computation of Earnings Per Share Amount Stock Option (in shares)	831,244	914,535	831,244	914,535
Dilutive Securities Included in Computation of Earnings Per Share Amount Restricted Stock (in shares)	19,165	31,666	19,165	31,666
Incremental Common Shares Attributable to Share-based Payment Arrangements, Total (in shares)	181,270	377,200	213,574	382,711
Share-based Payment Arrangement, Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)	898,167	703,250	898,167	703,250