Note 14 - Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Standard Product Warranty Accrual, Period Increase (Decrease), Total	$ 0	$ 0
Standard Product Warranty Accrual, Ending Balance	159		$ 159
Failure of Equipment to Be Remedied Under Warranty Provision [Member]
Loss Contingency Accrual, Ending Balance	$ 0		$ 176

Amount of loss contingency liability.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(1),(c)(5)
-URI http://asc.fasb.org/extlink&oid=123368208&loc=d3e12565-110249

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Period Type:	instant

- Definition

Amount of increase (decrease) in the standard product warranty accrual. Excludes extended product warranties.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123368208&loc=d3e12565-110249

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Namespace Prefix:
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Balance Type:
Period Type: