Note 4 - Stock-based Compensation (Details Textual) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015	Sep. 05, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized					500,000
The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	297,033
Allocated Share-based Compensation Expense, Total	$ 134,000	$ 223,000	$ 214,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total	$ 100,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 36 days
The 2012 Stock Incentive Plan [Member] | Total Unrecognized Compensation Including Portion Relating to Grants Not Expected to Be Awarded [Member]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total	$ 1,500,000
Employee Stock Purchase Plan ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance	70,515	77,285	63,915	54,307
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	63,607	55,766	52,836
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	52,816	31,503	27,705
Allocated Share-based Compensation Expense, Total	$ 130,000	$ 150,000	$ 140,000
The 2013 ESOP [Member]
Allocated Share-based Compensation Expense, Total	$ 0	$ 0	$ 0
Employee Stock Option [Member] | The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance	20,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	0	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	4 years 182 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 100,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	20,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0
Employee Stock Option [Member] | Employee Stock Purchase Plan ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	2 years
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	0
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent	85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum	40.88%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum	41.09%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum	1.68%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum	2.55%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	2 years
Restricted Stock Units (RSUs) [Member] | The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number, Ending Balance	140,802
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 1,400,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	62,000	45,000	40,200
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 7.22	$ 10.86	$ 15.11
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	12,433
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	14,400	12,732
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 900,000	$ 900,000
Minimum [Member] | Employee Stock Option [Member] | The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
Minimum [Member] | Employee Stock Option [Member] | Employee Stock Purchase Plan ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	4.32%
Minimum [Member] | Restricted Stock Units (RSUs) [Member] | The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
Maximum [Member] | Employee Stock Option [Member] | The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Maximum [Member] | Employee Stock Option [Member] | Employee Stock Purchase Plan ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	5.00%
Maximum [Member] | Restricted Stock Units (RSUs) [Member] | The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years