Note 9 - Debt (Details Textual)		1 Months Ended			9 Months Ended
	Nov. 22, 2011 USD ($)	Mar. 31, 2019 USD ($)	Jan. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018	Jun. 30, 2018 USD ($)
Line of Credit Facility, Maximum Borrowing Capacity			$ 23,000,000
Line of Credit Facility, Interest Rate During Period					4.00%	3.20%
Long-term Line of Credit, Total		$ 14,900,000			$ 14,900,000
Line of Credit Facility, Commitment Fee Percentage					0.25%
Minimum Consolidated Cash and Liquid Investments Pursuant to New Loan and Security Agreement					$ 10,000,000
Long-term Debt, Total		21,035,000			21,035,000		$ 20,962,000
Notes Payable to Banks [Member] | Santander Bank and Bradesco Bank [Member]
Debt Instrument, Face Amount				$ 3,500,000
Short-term Debt, Total		$ 1,300,000			$ 1,300,000
Notes Payable to Banks [Member] | Santander Bank [Member]
Debt Instrument, Face Amount				$ 1,500,000
Debt Instrument, Term				180 days
Debt Instrument, Interest Rate, Stated Percentage		5.30%		4.19%	5.30%
Short-term Debt, Total		$ 800,000			$ 800,000
Notes Payable to Banks [Member] | Bradesco Bank [Member]
Debt Instrument, Face Amount				$ 2,000,000
Debt Instrument, Term				360 days
Debt Instrument, Interest Rate, Stated Percentage		4.27%		4.75%	4.27%
Short-term Debt, Refinanced, Amount		$ 1,300,000
Short-term Debt, Total		500,000			$ 500,000
Term Loan [Member]
Debt Instrument, Face Amount	$ 15,500,000
Debt Instrument, Term	10 years
Debt Instrument, Interest Rate, Stated Percentage	4.50%
Debt Instrument, Periodic Payment, Total	$ 160,640
Long-term Debt, Total		$ 4,800,000			$ 4,800,000
Maximum [Member]
Current Funded Debt to EBITDA Ratio					2.25
Annual Capital Expenditures					$ 15,000,000
Debt Service Coverage Rate					1.25
Minimum [Member]
Current Funded Debt to EBITDA Ratio					1
Debt Service Coverage Rate					1
London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate			1.50%