Note 3 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions | 3 Months Ended |
Sep. 30, 2016 | Sep. 30, 2015 |
Employee Stock Option [Member] | The 2012 Stock Incentive Plan [Member] | Minimum [Member] | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 1 year | |
Employee Stock Option [Member] | The 2012 Stock Incentive Plan [Member] | Maximum [Member] | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 3 years | |
Employee Stock Option [Member] | The 2012 Stock Incentive Plan [Member] | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | 0 | 0 |
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 | 20,000 | |
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number | 105,634 | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term | 6 years 91 days | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number | 20,000 | |
Restricted Stock Units (RSUs) [Member] | The 2012 Stock Incentive Plan [Member] | Minimum [Member] | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 1 year | |
Restricted Stock Units (RSUs) [Member] | The 2012 Stock Incentive Plan [Member] | Maximum [Member] | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | 3 years | |
Restricted Stock Units (RSUs) [Member] | The 2012 Stock Incentive Plan [Member] | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | 45,000 | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ 10.86 | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period | 12,733 | |
The 2012 Stock Incentive Plan [Member] | Total Unrecognized Compensation Including Portion Relating to Grants Not Expected to Be Awarded [Member] | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value | $ 1 | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | 1.4 | |
The 2012 Stock Incentive Plan [Member] | Portion Relating to RSU Grants Not Expected to be Awarded [Member] | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ 1.1 | |
The 2012 Stock Incentive Plan [Member] | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | 346,600 | |
Allocated Share-based Compensation Expense | $ 0.1 | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $ 0.3 | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | 1 year 292 days | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | 500,000 | |