Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jul. 01, 2018
Cash, FDIC Insured Amount	$ 250,000
Cash, Uninsured Amount	4,507,000	$ 4,488,000
Depreciation, Total	7,462,000	7,005,000	$ 6,171,000
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Asset	$ 0
Standard Warranty Extended Term for Exceptions	10 years
Defined Contribution Plan, Cost	$ 1,195,214	2,373,000	2,327,000
Research and Development Expense, Total	$ 5,952,000	$ 5,700,000	$ 5,549,000
Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares	720,000	844,000	872,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	27.60%	34.00%	35.00%
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	$ 3,322,991
Retained Earnings (Accumulated Deficit), Ending Balance	$ 15,124,000	$ 39,819,000
Minimum [Member]
Media Content Service Period	30 days
Finite-Lived Intangible Asset, Useful Life	7 years
Standard Warranty Term	1 year
Minimum [Member] | Accounting Standards Update 2014-09 [Member] | Subsequent Event [Member]
Retained Earnings (Accumulated Deficit), Ending Balance				$ 600,000
Maximum [Member]
Media Content Service Period	1 year
Finite-Lived Intangible Asset, Useful Life	20 years
Standard Warranty Term	5 years
Maximum [Member] | Accounting Standards Update 2014-09 [Member] | Subsequent Event [Member]
Retained Earnings (Accumulated Deficit), Ending Balance				$ 1,000,000
Maximum [Member] | Leasehold Improvements [Member]
Property, Plant and Equipment, Useful Life	15 years