Note 8 - Goodwill and Other Intangible Assets (Details Textual)	3 Months Ended
Sep. 30, 2021
Number of Reporting Units	2
Display Solutions Segment [Member]
Number of Reporting Units	1
Lighting Segment [Member]
Number of Reporting Units	1

Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

No definition available.

Name:	us-gaap_NumberOfReportingUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration