Note 7 - Long-lived Assets (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Construction in Progress Expenditures Incurred but Not yet Paid	$ 1,227	$ 463
Amortization of Intangible Assets, Total	733	$ 733
Industrial Solutions [Member]
Goodwill and Intangible Asset Impairment, Total	$ 0
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	6 years
Minimum [Member] \| Red Wolf [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	1 year
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	20 years
Maximum [Member] \| Red Wolf [Member]
Finite-Lived Intangible Asset, Useful Life (Year)	6 years

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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