Organization And Summary Of Significant Accounting Policies (Schedule Of Product Warranty Liabilities) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Organization And Summary Of Significant Accounting Policies Schedule Of Product Warranty Liabilities
Balance at the beginning of the period	$ 247,850	$ 212,495
Amount accrued		180,797
Expenditures	115,919	145,442
Balance at period-end	$ 131,931	$ 247,850