Note 4 - Stock-based Compensation - Stock Options Outstanding Weighted Average Fair Value (Details) - Employee Stock Purchase Plan ESPP [Member] - $ / shares	12 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Weighted average remaining life (years) (Year)	1 year 109 days
2016 (in dollars per share)	$ 2.23	$ 2.76	$ 3.34

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant