Nature of Business and Summary of Significant Accounting Policies (Narrative) (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2017
Significant Accounting Policies [Line Items]
Carrying amount of long-term debt, including current portion	$ 2,000,000		$ 2,000,000		$ 3,500,000
Short-term time deposits	460,000		460,000		460,000
Intangible assets amortization expense	92,000	$ 110,000	185,000	$ 220,000
Estimated amortization expense-2018	371,000		371,000
Estimated amortization expense-2019	313,000		313,000
Estimated amortization expense-2020	264,000		264,000
Estimated amortization expense-2021	223,000		223,000
Estimated amortization expense-2022	$ 188,000		$ 188,000
Weighted average amortization period for acquired intangible assets			10 years 7 months 6 days	11 years 7 months 6 days
Antidilutive options outstanding excluded from diluted EPS computations	870	5,000	435	5,000
Stock-based compensation costs	$ 103,000	$ 65,000	$ 136,000	$ 98,000
Sales Returns And Allowances Percentage			8.00%	8.00%
Stock-based compensation costs, effect on EPS	$ 0.00	$ 0.00	$ 0.00	$ 0.00
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%		21.00%
Selling, General and Administrative Expenses [Member]
Significant Accounting Policies [Line Items]
Advertising and promotion costs	$ 462,000	$ 498,000	$ 1,103,000	$ 1,172,000
Sales revenue, net [Member]
Significant Accounting Policies [Line Items]
Shipping and handling revenue	252,000	217,000	459,000	433,000
Cost of sales [Member]
Significant Accounting Policies [Line Items]
Research and development costs	1,639,000	1,609,000	3,246,000	3,237,000
Shipping and handling expense	125,000	$ 105,000	247,000	$ 245,000
Allowance for doubtful accounts current [Member]
Significant Accounting Policies [Line Items]
Valuation allowances and reserves, balance	175,000		175,000		155,000
Returns and other allowances [Member]
Significant Accounting Policies [Line Items]
Valuation allowances and reserves, balance	$ 1,145,000		$ 1,145,000		$ 1,250,000