The estimated statutory income tax rate in the specified fiscal year.

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Aggregate number of common shares reserved for future issuance.

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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

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Number of additional shares authorized for issuance under an established share-based compensation plan.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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Gross number of share options (or share units) granted during the period.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Purchase price of common stock expressed as a percentage of its fair value.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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Note 9 - Employee Equity Incentive Plans (Details Textual) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Aug. 26, 2016	Aug. 30, 2013	Sep. 16, 2011	Sep. 10, 2009
Estimated Statutory Income Tax Rate		40.00%	40.00%
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 8,200	$ 8,200
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition		2 years 292 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	549,000
Dividends Payable	$ 0	$ 0		$ 0
Plan 2009 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized								900,000
Plan 2011 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized							600,000
Plan 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized						2,000,000
Plan 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized					2,000,000
Stock Options of Plans Two Thousand and Nine Two Thousand and Eleven Two Thousand and Thirteen and Two Thousand and Sixteen [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
Stock Options of Plans Two Thousand and Nine Two Thousand and Eleven Two Thousand and Thirteen and Two Thousand and Sixteen [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent		100.00%
Stock Appreciation Rights of Plans Two Thousand and Nine Two Thousand and Eleven Two Thousand and Thirteen and Two Thousand and Sixteen [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent		100.00%
Stock Appreciation Rights of Plans Two Thousand and Nine Two Thousand and Eleven Two Thousand and Thirteen and Two Thousand and Sixteen [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
Employee Stock Purchase Plan 1999 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,950,000	1,950,000
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, Maximum Employee Subscription Rate	15.00%	15.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans		57,422
Common Stock, Capital Shares Reserved for Future Issuance	470,648	470,648
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		400,000