Note 8 - Subsequent Events (Details Textual) - Forecast [Member] $ in Millions	3 Months Ended
Sep. 30, 2020 USD ($)
Bemidji and Mankato, Minnesota Facilities [Member]
Lessee, Operating Lease, Term of Contract (Year)	15 years
Manufacturing Facilities in Bemidji and Mankato, Minnesota [Member]
Expected Proceeds from Divestiture of Businesses	$ 5

Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918673-209980

Name:	us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant