Note 3 - Revenue from Contracts with Customers - Revenue from Contracts with Customers (Details) - USD ($)	3 Months Ended				6 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2018		Dec. 31, 2017
Net sales	$ 56,532,000	[1]	$ 52,124,000	[2]	$ 108,433,000	[1]	$ 103,942,000	[2]
North American Segment [Member]
Net sales	34,628,000	[1]	31,100,000	[2]	64,828,000	[1]	60,818,000	[2]
International Segment [Member]
Net sales	21,904,000		21,024,000		43,605,000		43,124,000
UNITED STATES | North American Segment [Member]
Net sales	32,413,000		28,899,000		60,360,000		56,358,000
Canada and Mexico [Member] | North American Segment [Member]
Net sales	2,215,000		2,201,000		4,468,000		4,460,000
BRAZIL | International Segment [Member]
Net sales	12,519,000		11,648,000		24,886,000		24,445,000
UNITED KINGDOM | International Segment [Member]
Net sales	5,657,000		6,146,000		11,673,000		12,327,000
CHINA | International Segment [Member]
Net sales	2,052,000		1,644,000		3,761,000		3,389,000
Australia and New Zealand [Member] | International Segment [Member]
Net sales	$ 1,676,000		$ 1,586,000		$ 3,285,000		$ 2,963,000

[1] Excludes $1,047 of North American segment intercompany sales to the International segment, and $3,744 of International segment intercompany sales to the North American segment.

[2] Excludes $1,581 of North American segment intercompany sales to the International segment, and $3,298 of International segment intercompany sales to the North American segment.