Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] |
| | 2017 | | 2016 | | | | | | | | | | Tax provision (benefit) | | | | | | | | Current | | | | | | | | Federal | | $ | | | $ | | | State | | | | | | | | Total current | | | | | | | | | | | | | | | | Deferred | | | | | | | | Federal | | | 13,626,404 | | | (4,053,114) | | State | | | 1,969,262 | | | 99,883 | | Total deferred | | | 15,595,666 | | | (3,953,231) | | | | | | | | | | Change in valuation allowance | | | (15,595,666) | | | 3,953,231 | | Total | | $ | | | $ |
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Schedule of Deferred Tax Assets and Liabilities [Table Text Block] |
Deferred tax assets consisted of the following at December 31: | | 2017 | | 2016 | | | | | | | | | | Deferred tax assets | | | | | | | | Federal net operating loss | | $ | 24,353,504 | | $ | 36,472,996 | | Federal research and development tax credit carryforwards | | | 4,947,879 | | | 3,808,862 | | State net operating losses and tax credit carryforwards | | | 1,589,927 | | | 2,628,006 | | Capitalized research and development expenses | | | 5,772,165 | | | 8,834,640 | | Stock-based compensation expense | | | 1,445,078 | | | 2,162,703 | | Depreciable assets | | | 166,793 | | | | | Other | | | 121,680 | | | 235,681 | | Total deferred tax assets | | | 38,397,026 | | | 54,142,888 | | | | | | | | | | Deferred tax liabilities | | | | | | | | Depreciable assets | | | | | | (150,196) | | Total deferred tax liabilities | | | | | | (150,196) | | | | | | | | | | Net deferred tax assets | | | 38,397,026 | | | 53,992,692 | | Less valuation allowance | | | (38,397,026) | | | (53,992,692) | | Total deferred tax assets | | $ | | | $ | |
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