Investments (Schedule of Held-To-Maturity Investments) (Details) - Certificates of deposit, tri-party repurchase agreement, corporate notes and bonds [Member] - USD ($) |
Sep. 30, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|---|---|---|---|
| Schedule of Trading Securities and Other Trading Assets [Line Items] | |||
| Amortized Cost | $ 6,742,987 | $ 10,698,982 | $ 17,297,165 |
| Gross Unrealized (Losses) | (2,814) | (2,209) | (16,493) |
| Estimated Fair Value | 6,740,173 | 10,696,773 | 17,280,672 |
| Less than 1 year | 6,742,987 | 10,698,982 | 17,297,165 |
| Total | $ 6,742,987 | $ 10,698,982 | $ 17,297,165 |