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Financial Condition (Details Narrative) - USD ($) | 6 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 | Dec. 31, 2018 | Dec. 31, 2017
Cumulated net losses |  | $ (273,665,247) | $ (261,781,888)
Cash, investment securities and interest receivable |  | 27,700,000 |
Common Stock Sales Agreement [Member] | Aspire Capital Fund, LLC [Member] |  |  |
Proceeds from available future sale of equity under common stock purchase agreement |  | 31,000,000 |
New Jersey [Member] |  |  |
Tax benefits of EDA |  | 11,100,000 |
New Jersey [Member] | Maximum [Member] |  |  |
Tax benefits of EDA | $ (12,500,000) |  |
New Jersey [Member] |  |  |
Tax benefits of EDA |  | 11,100,000 |
Unrecognized tax benefits |  | $ 3,900,000 |

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