Note 7 - Income Taxes (Details Textual) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Effective Income Tax Rate Reconciliation, Percent, Total	(3.00%)	4.50%	3.70%	2.60%
Unrecognized Tax Benefits, Period Increase (Decrease), Total	$ (0.2)		$ (0.5)

Amount of increase (decrease) in unrecognized tax benefits attributable to uncertain tax positions taken in tax returns.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

Name:	us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration