Organization And Summary Of Significant Accounting Policies (Schedule Of Product Warranty Liabilities) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Organization And Summary Of Significant Accounting Policies Schedule Of Product Warranty Liabilities
Balance at the beginning of the period	$ 212,495	$ 328,279
Amount accrued	132,852	59,981
Expenditures	54,395	175,765
Balance at period-end	$ 290,952	$ 212,495