Note 15 - Restructuring Costs (Details Textual) - USD ($)	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2016
Inventory Write-down	$ 2,088,000	$ 1,726,000	$ 1,493,000
Gain (Loss) on Disposition of Property Plant Equipment	1,361,000		$ 343,000
Restructuring Charges	1,419,000
Assets Held-for-sale, Not Part of Disposal Group, Current	1,463,000
Machinery and Equipment at the Kansas City and Beaverton Facilities [Member] | Lighting Segment [Member]
Impairment of Long-Lived Assets Held-for-use	322,000
Machinery and Equipment at the Kansas City and Beaverton Facilities [Member] | Technology Segment [Member]
Impairment of Long-Lived Assets Held-for-use	32,000
Closure of Kansas City Facility [Member]
Inventory Write-down	485,000
Gain (Loss) on Disposition of Property Plant Equipment	1,361,000
Restructuring and Related Cost, Expected Cost						$ 944,000
Closure of Kansas City Facility [Member] | Machinery and Equipment at the Kansas City and Beaverton Facilities [Member]
Impairment of Long-Lived Assets Held-for-use	354,000
Consolidation of Beaverton, Oregon Facility into Other LSI Facilities [Member]
Restructuring Charges	377,000
Consolidated of Woodsocket, Rhode Island Manufacturing Operation into its North Canton, Ohio Operation [Member]
Assets Held-for-sale, Not Part of Disposal Group, Current	1,463,000
Consolidation of Woonsocket, Rhode Island Manufacturing Operation into Its North Canton, Ohio Operation [Member]
Restructuring and Related Cost, Expected Cost						$ 500,000
Closure of Kansas City Facility and Consolidation of Beaverton, Oregon Facility Into Other LSI Facilities [Member] | Machinery and Equipment at the Kansas City and Beaverton Facilities [Member]
Impairment of Long-Lived Assets Held-for-use	$ 354,000