Nature of Business and Summary of Significant Accounting Policies (Narrative) (Detail) - USD ($)	3 Months Ended		6 Months Ended	9 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	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
Intangible assets amortization expense	93,000	$ 111,000		278,000	$ 331,000
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 4 months 24 days	11 years 3 months 18 days
Research and development costs	1,669,000	1,698,000		$ 4,915,000	$ 4,935,000
Antidilutive options outstanding excluded from diluted EPS computations				290	0
Stock-based compensation costs	$ 5,000	$ 0		$ 141,000	$ 97,000
Sales Returns And Allowances Percentage	7.00%	9.00%		8.00%	8.00%
Stock-based compensation costs, effect on EPS	$ 0.00	$ 0.00		$ 0.01	$ 0.01
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	$ 171,000	$ 365,000		$ 1,274,000	$ 1,537,000
Sales revenue, net [Member]
Significant Accounting Policies [Line Items]
Shipping and handling revenue	247,000	250,000		706,000	683,000
Cost of sales [Member]
Significant Accounting Policies [Line Items]
Research and development costs	1,669,000	1,698,000		4,915,000	4,935,000
Shipping and handling expense	105,000	$ 104,000		352,000	$ 349,000
Allowance for doubtful accounts current [Member]
Significant Accounting Policies [Line Items]
Valuation allowances and reserves, balance	180,000			180,000		155,000
Returns and other allowances [Member]
Significant Accounting Policies [Line Items]
Valuation allowances and reserves, balance	$ 1,115,000			$ 1,115,000		$ 1,250,000