Marketable Securities (Schedule Of Cost And Fair Value Of Marketable Securities) (Details) - USD ($) |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Schedule of Available-for-sale Securities [Line Items] | ||
| Cost Basis | $ 13,424,015 | $ 13,258,127 |
| Gross Unrealized Gains | 1,385 | 571 |
| Gross Unrealized Losses | (6,041) | (18,612) |
| Fair value | 13,419,359 | 13,240,086 |
| Commercial Paper [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Cost Basis | 5,974,806 | 2,981,307 |
| Gross Unrealized Gains | 406 | |
| Gross Unrealized Losses | (1,152) | (3,737) |
| Fair value | 5,974,060 | 2,977,570 |
| Corporate Bonds [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Cost Basis | 5,049,209 | 4,036,820 |
| Gross Unrealized Losses | (4,889) | (9,300) |
| Fair value | 5,044,320 | 4,027,520 |
| Certificates of Deposit [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Cost Basis | 2,400,000 | 6,240,000 |
| Gross Unrealized Gains | 979 | 571 |
| Gross Unrealized Losses | (5,575) | |
| Fair value | $ 2,400,979 | $ 6,234,996 |