Note 17 - Financial Information by Segment and Geographic Area (Details Textual) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2018 USD ($)		Jun. 30, 2017 USD ($)		Jun. 30, 2016 USD ($)		Jun. 30, 2015
Number of Reportable Segments									2						1
Revenues, Total	$ 57,552	$ 54,834	$ 52,124	$ 51,818	$ 54,253	$ 50,670	$ 53,187	$ 48,913	$ 216,328	[1]	$ 207,023	[2]	$ 209,685	[3]
North American Segment [Member]
Revenues, Total									128,442	[1]	124,606	[2]	130,108	[3]
North American Segment [Member] | Intersegment Eliminations [Member]
Revenues, Total									6,468		7,902		8,259
International Segment [Member]
Revenues, Total									87,886	[1]	82,417	[2]	79,577	[3]
International Segment [Member] | Intersegment Eliminations [Member]
Revenues, Total									$ 14,239		$ 11,677		$ 9,282

[1] Excludes $6,468 of North American segment intercompany sales to the International segment and $14,239 intercompany sales of the International segment to the North American segment.

[2] Excludes $7,902 of North American segment intercompany sales to the International segment and $11,677 intercompany sales of the International segment to the North American segment.

[3] Excludes $8,259 of North American segment intercompany sales to the International segment and $9,282 intercompany sales of the International segment to the North American segment.