Note 2 - Business Acquisitions - Preliminary Allocation of Intangible Assets (Details) - Kita Manufacturing Co. LTD. and Kita USA, Inc. [Member] - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Dec. 30, 2017
Gross carrying amount	$ 36,072	$ 35,212
Accumulated amortization	19,941	18,464
Developed Technology Rights [Member]
Gross carrying amount	21,263	20,780
Accumulated amortization	$ 13,567	12,623
Finite-lived intangible assets, average useful life (Year)	3 years 36 days
Customer Relationships [Member]
Gross carrying amount	$ 8,131	7,934
Accumulated amortization	$ 5,215	4,838
Finite-lived intangible assets, average useful life (Year)	2 years 292 days
Trade Names [Member]
Gross carrying amount	$ 6,347	6,185
Accumulated amortization	$ 1,118	972
Finite-lived intangible assets, average useful life (Year)	11 years 328 days
Noncompete Agreements [Member]
Gross carrying amount	$ 331	313
Accumulated amortization	$ 41	$ 31
Finite-lived intangible assets, average useful life (Year)	8 years 292 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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 928
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