Note 9 - Leases - Lease Expense (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
		Sep. 28, 2019	Sep. 28, 2019
Operating leases (1)	[1]	$ 2,142	$ 6,381
Variable lease expense		570	1,765
Short-term operating leases		80	224
Amortization of leased assets		20	82
Interest on lease liabilities		29	117
Sublease income		(31)	(101)
Net lease cost		$ 2,810	$ 8,468

[1] Operating lease cost excludes impairment expense of $0.2 million related to the write-down of the Fontana facility right-of-use asset.