Note 3 - Acquisition - Intangible Assets Acquired (Details) - USD ($) $ in Thousands		12 Months Ended
	May 24, 2017	Dec. 31, 2017
Finite-lived intangible assets		$ 10,100
Acquisition of Ambrell		$ 10,100
Ambrell [Member]
Finite-lived intangible assets	$ 10,100
Finite-lived intangible assets, weighted average estimated useful life (Year)	8 years 219 days
Acquisition of Ambrell	$ 10,100
Identifiable intangible assets	16,300
Ambrell [Member] | Trademarks [Member]
Indefinite-lived intangible assets	6,200
Ambrell [Member] | Customer Relationships [Member]
Finite-lived intangible assets	$ 9,000
Finite-lived intangible assets, weighted average estimated useful life (Year)	9 years
Acquisition of Ambrell	$ 9,000
Ambrell [Member] | Patented Technology [Member]
Finite-lived intangible assets	$ 600
Finite-lived intangible assets, weighted average estimated useful life (Year)	9 years
Acquisition of Ambrell	$ 600
Ambrell [Member] | Order or Production Backlog [Member]
Finite-lived intangible assets	$ 500
Finite-lived intangible assets, weighted average estimated useful life (Year)	109 days
Acquisition of Ambrell	$ 500