Note 3 - Acquisitions - Fair Value of Net Assets Acquired (Details) - USD ($)	Jun. 30, 2020	Dec. 31, 2019	Nov. 12, 2019	Nov. 11, 2019	Aug. 08, 2019	Aug. 07, 2019	Apr. 01, 2019	Mar. 31, 2019
Goodwill	$ 33,506,000	$ 33,637,000
Astero [Member]
Cash and cash equivalents								$ 11,000
Accounts receivable, net								154,000
Inventory								456,000
Intangible assets							$ 4,120,000
Goodwill							9,500,000	9,515,000
Other assets								99,000
Accounts payable								(250,000)
Other liabilities								164,000
Fair value of net assets acquired								13,941,000
Other liabilities								(164,000)
Fair value of net assets acquired								13,941,000
Inventory								456,000
Astero [Member] | Customer Relationships [Member]
Intangible assets							160,000	160,000
Astero [Member] | Trade Names [Member]
Intangible assets							470,000	470,000
Astero [Member] | Developed Technology Rights [Member]
Intangible assets							2,840,000	2,840,000
Astero [Member] | In Process Research and Development [Member]
Intangible assets							$ 650,000	$ 650,000
SAVSU [Member]
Cash and cash equivalents						$ 1,251,000
Accounts receivable, net						753,000
Intangible assets					$ 12,150,000
Goodwill					19,500,000	21,037,000
Accounts payable						(807,000)
Other liabilities						232,000
Fair value of net assets acquired					35,800,000	35,850,000
Prepaid expenses and other current assets						19,000
Property, plant and equipment, net						546,000
Operating right-of-use asset					233,000	233,000
Assets held for rent, net						2,441,000
Deferred tax liabilities						(1,541,000)
Other liabilities						(232,000)
Fair value of net assets acquired					35,800,000	35,850,000
SAVSU [Member] | Customer Relationships [Member]
Intangible assets					80,000	80,000
SAVSU [Member] | Trade Names [Member]
Intangible assets					$ 1,320,000	1,320,000
SAVSU [Member] | Developed Technology Rights [Member]
Intangible assets						$ 10,750,000
CBS Acquisition [Member]
Accounts receivable, net				$ 1,044,000
Inventory				3,232,000
Intangible assets			$ 6,800,000	6,790,000
Goodwill			$ 3,100,000	2,954,000
Accounts payable				(1,197,000)
Other liabilities				611,000
Fair value of net assets acquired				15,856,000
Prepaid expenses and other current assets				29,000
Property, plant and equipment, net				3,615,000
Other liabilities				(611,000)
Fair value of net assets acquired				15,856,000
Inventory				3,232,000
CBS Acquisition [Member] | Customer Relationships [Member]
Intangible assets				560,000
CBS Acquisition [Member] | Trade Names [Member]
Intangible assets				800,000
CBS Acquisition [Member] | Developed Technology Rights [Member]
Intangible assets				$ 5,430,000