Note 14 - Restructuring Costs (Details Textual) - USD ($)	9 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jun. 30, 2017	Dec. 31, 2017
Inventory Write-down	$ 1,762,000	$ 981,000
Gain (Loss) on Disposition of Property Plant Equipment, Total		1,361,000
Restructuring Charges, Total
Closure of Kansas City Facility [Member]
Restructuring and Related Cost, Expected Cost, Total			$ 944,000	$ 0
Inventory Write-down		$ 432,000	485,000
Gain (Loss) on Disposition of Property Plant Equipment, Total			1,361,000
Consolidation of Beaverton, Oregon Facility into Other LSI Facilities [Member]
Restructuring Charges, Total			377,000
Consolidation of Woonsocket, Rhode Island Manufacturing Operation into Its North Canton, Ohio Operation [Member]
Restructuring and Related Cost, Expected Cost, Total			$ 452,000
Restructuring Charges, Total	$ 0