Note 9 - Leases - Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Operating leases	$ 2,112	$ 2,139	$ 4,263	$ 4,261
Variable lease expense	547	635	1,079	1,201
Short-term operating leases	19	66	38	144
Amortization of leased assets	28	21	48	62
Interest on lease liabilities	29	29	57	88
Sublease income	(31)	(34)	(63)	(70)
Net lease cost	$ 2,704	$ 2,856	$ 5,422	$ 5,686

Amount of interest expense on finance lease liability.

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Amount of amortization expense attributable to right-of-use asset from finance lease.

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- Definition

Amount of lease cost recognized by lessee for lease contract.

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Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

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Amount of short-term lease cost, excluding expense for lease with term of one month or less.

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Amount of sublease income excluding finance and operating lease expense.

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Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

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