Note 13 - Acquisition - Assets Acquires and Liabilities Assumed (Details) - USD ($) $ in Thousands	Feb. 01, 2018	Jun. 30, 2019	Dec. 31, 2018
Goodwill		$ 51,838	$ 51,838
Dielectrics [Member]
Cash paid at closing	$ 80,000
Working capital adjustment	250
Cash from Dielectrics	(3,272)
Total consideration	76,978
Accounts receivable	4,384
Inventory	4,418
Other current assets	122
Property, plant and equipment	4,600
Goodwill	44,516
Total identifiable assets	81,424
Accounts payable	(1,325)
Accrued expenses	(946)
Deferred revenue	(2,175)
Net Assets acquired	76,978
Dielectrics [Member] | Customer Lists [Member]
Intangible assets	22,555
Dielectrics [Member] | Noncompete Agreements [Member]
Intangible assets	462
Dielectrics [Member] | Trade Name and Brand [Member]
Intangible assets	$ 367