Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
License revenue	$ 26,689	$ 4,938	$ 36,565	$ 168,341
Research grants and contracts	4,565,251	896,101	7,892,919	1,983,574
Total revenue and grants and contracts	4,591,940	901,039	7,929,484	2,151,915
Operating expenses
Research and development	5,905,552	2,400,914	13,946,403	4,845,045
General and administrative	3,038,756	3,289,647	6,863,782	5,301,444
Goodwill impairment charges	26,600,000		26,600,000
Total operating expenses	35,544,308	5,690,561	47,410,185	10,146,489
Loss from operations	(30,952,368)	(4,789,522)	(39,480,701)	(7,994,574)
Other income (expense):
Change in fair value of warrant liabilities	(508,316)		(508,316)
Change in fair value of embedded derivative	(1,157)		(1,157)
Interest expense	(2,344)	(9,408)	(160,103)	(28,858)
Interest income	15,372		19,538	1,047
Other income (expense)	10,786	3,871	9,839	(2,600)
Total other income (expense), net	(485,659)	(5,537)	(640,199)	(30,411)
Net loss before income tax benefit	(31,438,027)	(4,795,059)	(40,120,900)	(8,024,985)
Income tax benefit	1,532,790		2,526,499
Net loss	(29,905,237)	(4,795,059)	(37,594,401)	(8,024,985)
Other comprehensive loss - foreign currency translation adjustments	(1,028,033)	(1,316,787)	(2,864,839)	(5,121,081)
Total comprehensive loss	(30,933,270)	(6,111,846)	(40,459,240)	(13,146,066)
Net loss	(29,905,237)	(4,795,059)	(37,594,401)	(8,024,985)
Preferred stock accretion and dividends	(1,962,072)	(104,548)	(2,125,141)	(247,562)
Net loss attributed to common stockholders	$ (31,867,309)	$ (4,899,607)	$ (39,719,542)	$ (8,272,547)
Weighted-average common shares outstanding, basic and diluted	15,527,867	6,911,715	11,595,698	6,911,366
Net loss per share attributed to common stockholders, basic and diluted	$ (2.05)	$ (0.71)	$ (3.43)	$ (1.20)