Note 3 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
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] | 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] | 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
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	20,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	7 years
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
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	73,367
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	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	$ 15.11
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	9,067
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 1.2
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	1.1
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	$ 0.7
The 2012 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	391,600
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 0.4
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	2 years 73 days
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, Number of Shares Authorized	500,000
Allocated Share-based Compensation Expense	$ 0.2	$ 0.1