Quarterly Financial Data (unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Data
Revenue				$ 7,250	$ 49,275	$ 199,407	$ 15,390	$ 14,828	$ 7,250	$ 278,900	$ 810,012
Operating expenses:
Research and development	$ 4,904,363	$ 4,504,097	$ 4,807,177	2,568,989	3,309,008	2,271,968	1,010,989	853,704	16,784,626	7,445,669	2,401,406
General and administrative	1,780,304	1,493,461	1,476,357	1,680,130	2,156,388	1,922,755	631,474	653,773	6,430,252	5,364,390	4,076,339
Total operating expenses	6,684,667	5,997,558	6,283,534	4,249,119	5,465,396	4,194,723	1,642,463	1,507,477	23,214,878	12,810,059	6,477,745
Loss from operations	(6,684,667)	(5,997,558)	(6,283,534)	(4,241,869)	(5,416,121)	(3,995,316)	(1,627,073)	(1,492,649)	(23,207,628)	(12,531,159)	(5,667,733)
Other income (expense):
Interest income (expense), net	26,980	22,747	18,118	12,377	4,403	1,572	697	680	80,222	7,352	(1,844)
Foreign exchange loss	(139,829)	(6,270)	(20,250)	(23,148)					(189,497)
Loss on disposal of equipment	(99,147)								(99,147)
Total other income (expense)	(211,996)	16,477	(2,132)	(10,771)					(208,422)	7,352	(1,844)
Loss before income taxes	(6,896,663)	(5,981,081)	(6,285,666)	(4,252,640)	(5,411,718)	(3,993,744)	(1,626,376)	(1,491,969)	(23,416,050)	(12,523,807)	(5,669,577)
Income tax expense (benefit)			56,277	(28,734)	(27,543)				(27,543)	27,543
Net loss applicable to common stockholders	$ (6,896,663)	$ (5,981,081)	$ (6,229,389)	$ (4,281,374)	$ 5,439,261	$ 3,993,744	$ 1,626,376	$ 1,491,969	$ (23,388,507)	$ (12,551,350)	$ (5,757,531)
Per share information:
Net loss per share basic and diluted	$ (0.71)	$ (0.67)	$ (0.70)	$ (0.49)	$ (0.62)	$ (0.66)	$ (1.12)	$ (1.03)	$ (2.58)	$ (2.82)	$ (6.44)
Basic and diluted weighted average shares outstanding	9,678,924	8,912,508	8,860,592	8,823,951	8,787,855	6,045,211	1,449,865	1,449,865	9,070,232	4,457,719	894,575
Previously Reported
Per share information:
Net loss per share basic and diluted							$ (0.80)	$ (0.74)