Note 4 - Segment Reporting Information - Intersegment Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Revenue from Contract with Customer, Including Assessed Tax	$ 106,397	$ 70,006
Lighting Segment [Member]
Revenue from Contract with Customer, Including Assessed Tax	51,260	45,405
Display Solutions Segment [Member]
Revenue from Contract with Customer, Including Assessed Tax	55,137	24,601
Intersegment Eliminations [Member] | Lighting Segment [Member]
Revenue from Contract with Customer, Including Assessed Tax	10,457	4,080
Intersegment Eliminations [Member] | Display Solutions Segment [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 163	$ 38