Note 2 - Business Acquisitions - Preliminary Allocation of Intangible Assets (Details) - Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member] - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Dec. 30, 2017
Gross carrying amount	$ 34,736	$ 35,212
Accumulated amortization	20,237	18,464
Developed Technology Rights [Member]
Gross carrying amount	20,498	20,780
Accumulated amortization	$ 13,721	12,623
Finite-lived intangible assets, average useful life (Year)	2 years 328 days
Customer Relationships [Member]
Gross carrying amount	$ 7,836	7,934
Accumulated amortization	$ 5,281	4,838
Finite-lived intangible assets, average useful life (Year)	2 years 182 days
Trade Names [Member]
Gross carrying amount	$ 6,084	6,185
Accumulated amortization	$ 1,187	972
Finite-lived intangible assets, average useful life (Year)	11 years 255 days
Noncompete Agreements [Member]
Gross carrying amount	$ 318	313
Accumulated amortization	$ 48	$ 31
Finite-lived intangible assets, average useful life (Year)	8 years 182 days

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 928
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