Marketable Securities (Narrative) (Details) |
Dec. 31, 2017
USD ($)
item
|
Dec. 31, 2016
USD ($)
|
|---|---|---|
| Schedule of Available-for-sale Securities [Line Items] | ||
| Fair value | $ 17,931,941 | $ 8,737,107 |
| Unrealized losses | $ 56,886 | $ 6,319 |
| 3 Commercial Paper With Unrealized Losses [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Securities in a loss position | item | 3 | |
| Fair value | $ 3,238,500 | |
| Unrealized losses | $ 2,505 | |
| 15 Corporate Bond With Unrealized Losses [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Securities in a loss position | item | 15 | |
| Fair value | $ 14,693,441 | |
| Unrealized losses | $ 54,381 |
| X | ||||||||||
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Number of investment positions in available-for-sale investments that have been in a continuous unrealized loss position for greater than or equal to a year for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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