| Schedule of Segment Reporting Information, by Segment [Table Text Block] | 
   
Three Months Ended September 
 30 
, 2019 
   |    |     |    |    |     |    |    |     |    |    |     |    |     |   Royalty revenue   |    |  $ |  4,895  |    |    |  $ |  —  |    |    |  $ |  —  |    |    |  $ |  4,895  |    |     |   Grant and other revenue   |    |    |  77,049  |    |    |    |  154,867  |    |    |    |  —  |    |    |    |  231,916  |    |     |   Total revenue   |    |    |  81,944  |    |    |    |  154,867  |    |    |    |  —  |    |    |    |  236,811  |    |     |   Cost of revenue   |    |    |  195  |    |    |    |  —  |    |    |    |  —  |    |    |    |  195  |    |     |   Research and development expenses   |    |    |  1,678,423  |    |    |    |  123,135  |    |    |    |  —  |    |    |    |  1,801,558  |    |      Selling, general and administrative expenses, excluding depreciation and amortization  (1) 
   |    |    |  —  |    |    |    |  1,052  |    |    |    |  1,484,155  |    |    |    |  1,485,207  |    |      Depreciation and amortization  (2) 
   |    |    |  —  |    |    |    |  —  |    |    |    |  34,289  |    |    |    |  34,289  |    |      (Loss) income from operations  (3) 
   |    |    |  (1,596,674  |    )   |    |    |  30,680  |    |    |    |  (1,518,444  |    )   |    |    |  (3,084,438  |    )   |     |    |    |    |  —  |    |    |    |  —  |    |    |    |  10,334  |    |    |    |  10,334  |    |     |   Income tax (expense) benefit   |    |    |  (72  |    )   |    |    |  16  |    |    |    |  55  |    |    |    |  —  |    |     |   Net (loss) income   |    |    |  (1,596,746  |    )   |    |    |  30,696  |    |    |    |  (1,508,055  |    )   |    |    |  (3,074,104  |    )   |     |   Total assets, net of depreciation and amortization:   |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |     |   United States   |    |  $ |  36,811  |    |    |  $ |  93,860  |    |    |  $ |  4,688,379  |    |    |  $ |  4,819,050  |    |     |   International   |    |    |  2,606  |    |    |    |  —  |    |    |    |  —  |    |    |    |  2,606  |    |     |   Capital expenditures   |    |    |  —  |    |    |    |  —  |    |    |    |  —  |    |    |    |  —  |    |      
   
T 
hree Months Ended September 30, 2018 
   |    |     |    |    |     |    |    |     |    |    |     |    |     |   Royalty revenue   |    |  $ |  2,382  |    |    |  $ |  —  |    |    |  $ |  —  |    |    |  $ |  2,382  |    |     |   License revenue   |    |    |  19,930  |    |    |    |  —  |    |    |    |  —  |    |    |    |  19,930  |    |     |   Grant and other revenue   |    |    |  65,505  |    |    |    |  143,641  |    |    |    |  —  |    |    |    |  209,146  |    |     |   Total revenue   |    |    |  87,817  |    |    |    |  143,641  |    |    |    |  —  |    |    |    |  231,458  |    |     |   Cost of revenue   |    |    |  38,101  |    |    |    |  —  |    |    |    |  —  |    |    |    |  38,101  |    |     |   Research and development expenses   |    |    |  711,355  |    |    |    |  514,415  |    |    |    |  —  |    |    |    |  1,225,770  |    |      Selling, general and administrative expenses, excluding depreciation and amortization  (1) 
   |    |    |  —  |    |    |    |  20,532  |    |    |    |  2,630,581  |    |    |    |  2,651,113  |    |      Depreciation and amortization  (2) 
   |    |    |  —  |    |    |    |  —  |    |    |    |  37,590  |    |    |    |  37,590  |    |     |    |    |    |  (661,639  |    )   |    |    |  (391,306  |    )   |    |    |  (2,668,171  |    )   |    |    |  (3,721,116  |    )   |     |    |    |    |  —  |    |    |    |  —  |    |    |    |  (24,534  |    )   |    |    |  (24,534  |    )   |     |   Income tax expense   |    |    |  (10,081  |    )   |    |    |  (3,879  |    )   |    |    |  (62,299  |    )   |    |    |  (76,259  |    )   |     |   Net loss   |    |    |  (671,720  |    )   |    |    |  (395,185  |    )   |    |    |  (2,755,004  |    )   |    |    |  (3,821,909  |    )   |     |   Total assets, net of depreciation and amortization:   |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |     |   United States   |    |  $ |  117,722  |    |    |  $ |  72,622  |    |    |  $ |  8,899,301  |    |    |  $ |  9,089,645  |    |     |   International   |    |    |  18,239  |    |    |    |  —  |    |    |    |  1,158  |    |    |    |  19,397  |    |     |   Capital expenditures   |    |    |  —  |    |    |    |  —  |    |    |    |  16,152  |    |    |    |  16,152  |    |      
   
Nine 
 Months Ended  
September 
 30, 2019 
   |    |     |    |    |     |    |    |     |    |    |     |    |     |   Royalty revenue   |    |  $ |  13,985  |    |    |  $ |  —  |    |    |  $ |  —  |    |    |  $ |  13,985  |    |     |   License revenue   |    |    |  9,953  |    |    |    |  —  |    |    |    |  —  |    |    |    |  9,953  |    |     |   Grant and other revenue   |    |    |  309,670  |    |    |    |  204,919  |    |    |    |  —  |    |    |    |  514,589  |    |     |   Total revenue   |    |    |  333,608  |    |    |    |  204,919  |    |    |    |  —  |    |    |    |  538,527  |    |     |   Cost of revenue   |    |    |  6,559  |    |    |    |  —  |    |    |    |  —  |    |    |    |  6,559  |    |     |   Research and development expenses   |    |    |  3,194,468  |    |    |    |  418,315  |    |    |    |  —  |    |    |    |  3,612,783  |    |      Selling, general and administrative expenses, excluding depreciation and amortization  (1) 
   |    |    |  —  |    |    |    |  15,828  |    |    |    |  4,985,990  |    |    |    |  5,001,818  |    |      Depreciation and amortization  (2) 
   |    |    |  —  |    |    |    |  —  |    |    |    |  107,794  |    |    |    |  107,794  |    |     |    |    |    |  (2,867,419  |    )   |    |    |  (229,224  |    )   |    |    |  (5,093,784  |    )   |    |    |  (8,190,427  |    )   |     |    |    |    |  —  |    |    |    |  —  |    |    |    |  17,456  |    |    |    |  17,456  |    |     |   Provision for income tax   |    |    |  (248  |    )   |    |    |  (20  |    )   |    |    |  (439  |    )   |    |    |  (707  |    )   |     |   Net loss from continuing operations   |    |    |  (2,867,667  |    )   |    |    |  (229,244  |    )   |    |    |  (5,076,767  |    )   |    |    |  (8,173,678  |    )   |     |   Loss from discontinued operations, net of tax   |    |    |  (2,665  |    )   |    |    |  —  |    |    |    |  —  |    |    |    |  (2,665  |    )   |     |   Net loss   |    |    |  (2,870,332  |    )   |    |    |  (229,244  |    )   |    |    |  (5,076,767  |    )   |    |    |  (8,176,343  |    )   |     |   Total assets, net of depreciation and amortization:   |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |     |   United States   |    |  $ |  36,811  |    |    |  $ |  93,860  |    |    |  $ |  4,688,379  |    |    |  $ |  4,819,050  |    |     |   International   |    |    |  2,606  |    |    |    |  —  |    |    |    |  —  |    |    |    |  2,606  |    |     |   Capital expenditures   |    |    |  —  |    |    |    |  —  |    |    |    |  —  |    |    |    |  —  |    |      
   Nine Months Ended September 30, 2018    |    |     |    |    |     |    |    |     |    |    |     |    |     |   Royalty revenue   |    |  $ |  9,842  |    |    |  $ |  —  |    |    |  $ |  —  |    |    |  $ |  9,842  |    |     |   License revenue   |    |    |  277,639  |    |    |    |  —  |    |    |    |  —  |    |    |    |  277,639  |    |     |   Grant and other revenue   |    |    |  454,830  |    |    |    |  307,719  |    |    |    |  —  |    |    |    |  762,549  |    |     |   Total revenue   |    |    |  742,311  |    |    |    |  307,719  |    |    |    |  —  |    |    |    |  1,050,030  |    |     |   Cost of revenue   |    |    |  73,811  |    |    |    |  —  |    |    |    |  —  |    |    |    |  73,811  |    |     |   Research and development expenses   |    |    |  2,409,524  |    |    |    |  957,920  |    |    |    |  —  |    |    |    |  3,367,444  |    |      Selling, general and administrative expenses, excluding depreciation and amortization  (1) 
   |    |    |  —  |    |    |    |  45,769  |    |    |    |  6,095,617  |    |    |    |  6,141,386  |    |      Depreciation and amortization  (2) 
   |    |    |  —  |    |    |    |  —  |    |    |    |  113,088  |    |    |    |  113,088  |    |     |    |    |    |  (1,741,024  |    )   |    |    |  (695,970  |    )   |    |    |  (6,208,705  |    )   |    |    |  (8,645,699  |    )   |     |    |    |    |  —  |    |    |    |  —  |    |    |    |  (4,284,014  |    )   |    |    |  (4,284,014  |    )   |     |   Income tax expense   |    |    |  (8,797  |    )   |    |    |  (3,517  |    )   |    |    |  (53,017  |    )   |    |    |  (65,330  |    )   |     |   Net loss from continuing operations   |    |    |  (1,749,821  |    )   |    |    |  (699,487  |    )   |    |    |  (10,545,736  |    )   |    |    |  (12,995,043  |    )   |     |   Loss from discontinued operations, net of tax   |    |    |  (1,938  |    )   |    |    |  —  |    |    |    |  —  |    |    |    |  (1,938  |    )   |     |   Gain on sale of discontinued operations, net of tax   |    |    |  43,053  |    |    |    |  —  |    |    |    |  —  |    |    |    |  43,053  |    |     |   Net loss   |    |    |  (1,708,706  |    )   |    |    |  (699,487  |    )   |    |    |  (10,545,736  |    )   |    |    |  (12,953,928  |    )   |     |   Total assets, net of depreciation and amortization:   |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |     |   United States   |    |  $ |  117,722  |    |    |  $ |  72,622  |    |    |  $ |  8,899,301  |    |    |  $ |  9,089,645  |    |     |   International   |    |    |  18,239  |    |    |    |  —  |    |    |    |  1,158  |    |    |    |  19,397  |    |     |   Capital expenditures   |    |    |  —  |    |    |    |  —  |    |    |    |  19,317  |    |    |    |  19,317  |    |      
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