| Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] |
The following table represents the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis: | | | As of September 30, 2016 | | | | | Level 1 | | Level 2 | | Level 3 | | Balance | | | | | | | | | | | | | | | | | | Financial Assets | | | | | | | | | | | | | | | Cash equivalents | | $ | 13,899,719 | | $ | 54,964,977 | | $ | - | | $ | 68,864,696 | | | Short-term investments | | | - | | | 66,841,690 | | | - | | | 66,841,690 | | | Total financial assets measured at fair value | | $ | 13,899,719 | | $ | 121,806,667 | | $ | - | | $ | 135,706,386 | | | | | | | | | | | | | | | | | | Financial Liabilities | | | | | | | | | | | | | | | Current portion of derivative instruments related to stock purchase warrants | | $ | - | | $ | - | | $ | 1,150,845 | | $ | 1,150,845 | | | Total financial liabilities measured at fair value | | $ | - | | $ | - | | $ | 1,150,845 | | $ | 1,150,845 | | | | | As of December 31, 2015 | | | | | Level 1 | | Level 2 | | Level 3 | | Balance | | | | | | | | | | | | | | | | | | Financial Assets | | | | | | | | | | | | | | | Cash equivalents | | $ | 6,430,561 | | $ | - | | $ | - | | $ | 6,430,561 | | | Total financial assets measured at fair value | | $ | 6,430,561 | | $ | - | | $ | - | | $ | 6,430,561 | | | | | | | | | | | | | | | | | | Financial Liabilities | | | | | | | | | | | | | | | Current portion of derivative instruments related to stock purchase warrants | | $ | - | | $ | - | | $ | 16,411 | | $ | 16,411 | | | Non-current portion of derivative instruments related to stock purchase warrants | | | - | | | - | | | 491,791 | | | 491,791 | | | Total financial liabilities measured at fair value | | $ | - | | $ | - | | $ | 508,202 | | $ | 508,202 | |
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| Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] |
The following table sets forth a summary of changes in the fair value of the Company’s Level 3 liabilities for the nine months ended September 30, 2016 and 2015: | | | Balance as of | | Unrealized | | Balance as of | | | | | December 31, | | Losses (Gains) | | September 30, | | | Description | | 2015 | | 2016 | | 2016 | | | Derivative liabilities related to stock purchase warrants | | $ | 508,202 | | $ | 642,643 | | $ | 1,150,845 | | | | | Balance as of | | Unrealized | | Balance as of | | | | | December 31, | | Losses (Gains) | | September 30, | | | Description | | 2014 | | 2015 | | 2015 | | | Derivative liabilities related to stock purchase warrants | | $ | 807,679 | | $ | (577,426) | | $ | 230,253 | |
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