Nature of Business and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 01, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2020
Significant Accounting Policies [Line Items]
Short-term time deposits		$ 460,000		$ 460,000		$ 460,000
Intangible assets amortization expense		107,000	$ 66,000	213,000	$ 132,000
Estimated amortization expense- 2021		425,000		425,000
Estimated amortization expense- 2022		390,000		390,000
Estimated amortization expense - 2023		362,000		362,000
Estimated amortization expense - 2024		336,000		336,000
Estimated amortization expense - 2025		315,000		$ 315,000
Weighted average remaining amortization period for acquired intangible assets				17 years 2 months 12 days		17 years 6 months
Research and development costs		$ 1,884,000	$ 1,823,000	$ 3,773,000	$ 3,572,000
Antidilutive options outstanding excluded from diluted EPS computations		32,000	36,000	36,000	18,000
Stock-based compensation expense		$ 84,000	$ 308,000	$ 188,000	$ 325,000
Foreign Currency Transaction Gain (Loss), before Tax		0	0	$ 0	0
Number of Operating Segments				1
Cost of Goods and Services Sold		15,802,000	13,702,000	$ 28,283,000	28,469,000
Operating Lease, Liability	$ 7,700,000
Operating Lease, Right-of-Use Asset	$ 7,700,000	7,384,000		7,384,000		$ 7,395,000
Package of practical expedients	true
Selling, General and Administrative Expenses [Member]
Significant Accounting Policies [Line Items]
Advertising and promotion costs		347,000	627,000	690,000	1,141,000
Sales revenue, net [Member] | Shipping and Handling [Member]
Significant Accounting Policies [Line Items]
Cost of Goods and Services Sold		230,000	271,000	451,000	531,000
Cost of sales [Member]
Significant Accounting Policies [Line Items]
Research and development costs		1,884,000	1,823,000	3,773,000	3,572,000
Cost of sales [Member] | Shipping and Handling [Member]
Significant Accounting Policies [Line Items]
Cost of Goods and Services Sold		93,000	$ 108,000	199,000	$ 220,000
Allowance for doubtful accounts current
Significant Accounting Policies [Line Items]
Valuation allowances and reserves, balance		$ 196,000		$ 196,000		$ 326,000
Trade name
Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life				20 years
Impairment of intangible asset				$ 1,852,000