Note 6 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	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	169,533
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	3 years 91 days
Share-based Payment Arrangement, Expense	$ 0.1	$ 0.1
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 0.5
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 36 days
The 2012 Stock Incentive Plan [Member] | Portion Relating to RSU Grants Not Expected to be Awarded [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 1.4
Share-based Payment Arrangement, 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
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 0.1
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
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	212,507
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 1.2
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	60,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 5.52
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	44,995
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	0
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total	$ 1.9
Minimum [Member] | Share-based Payment Arrangement, Option [Member] | The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	1 year
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] | Share-based Payment Arrangement, Option [Member] | The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
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