Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Operating expenses:        
Research and development $ 444,817 $ 3,073,344 $ 3,043,802 $ 4,271,659
Acquired in-process research and development 32,266,893 0 32,266,893 0
General and administrative 5,659,721 3,049,711 7,329,528 6,164,206
Warrant inducement expense 6,467,048 0 7,157,887 0
Total operating expenses 44,838,479 6,123,055 49,798,110 10,435,865
Loss from operations (44,838,479) (6,123,055) (49,798,110) (10,435,865)
Other income (expense):        
Interest income 8,550 72,641 21,365 99,097
Interest expense (1,019,307) (431,626) (1,592,292) (858,871)
Loss on extinguishment of convertible note payable 0 0 0 (1,049,166)
Change in fair value of derivative liability and extinguishment of derivative liability 193,000 181,000 531,000 652,000
Change in fair value of warrant liabilities 1,058,700 1,812,800 2,637,500 2,669,800
Total other income (expense), net 240,943 1,634,815 1,597,573 1,512,860
Loss before income taxes (44,597,536) (4,488,240) (48,200,537) (8,923,005)
Benefit from income taxes 0 0 0 0
Net loss $ (44,597,536) $ (4,488,240) $ (48,200,537) $ (8,923,005)
Net loss per common share, basic and diluted (in usd per share) $ (0.57) $ (0.13) $ (0.81) $ (0.29)
Weighted-average common shares, basic and diluted (in shares) 78,584,900 33,973,788 59,873,598 30,631,601