Note 1 - Summary of Significant Accounting Policies - Reported Share-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Allocated share-based compensation	$ 3,662	$ 1,948	$ 7,355	$ 3,617
Income tax benefit	(79)	(126)	(359)	(440)
Total share-based compensation, net	3,583	1,822	6,996	3,177
Cost of Sales [Member]
Allocated share-based compensation	208	162	333	283
Research and Development Expense [Member]
Allocated share-based compensation	776	395	1,414	744
Selling, General and Administrative Expenses [Member]
Allocated share-based compensation	$ 2,678	$ 1,391	$ 5,608	$ 2,590

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration