Going Concern - Additional Information (Detail) - USD ($)	3 Months Ended				9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents, at Carrying Value	$ 8,044,199				$ 8,044,199				$ 7,585,392
Net Income (Loss) Attributable to Parent	(7,219,215)	$ 5,801,220			(12,610,083)	$ 32,460,894
Gain (Loss) on Derivative Instruments, Net, Pretax	(2,054,561)	7,744,708			(1,232,925)	41,110,851
Operating Expenses	5,172,679	1,940,298			11,430,033	8,646,767
Net Cash Provided by (Used in) Operating Activities					(10,631,693)	(9,812,379)
Retained Earnings (Accumulated Deficit)	(183,612,591)				(183,612,591)				(171,002,508)
Stockholders' deficit	4,137,259	$ 2,236,877	$ (3,768,672)	$ (8,856,812)	4,137,259	2,236,877	$ 11,110,453	$ (467,983)	$ 5,236,096	$ (34,176,885)
Stock Issued During Period, Value, Stock Options Exercised			$ 235,651	$ 400,759
Cash requirements for fixed, on-going expenses such as payroll, legal and accounting, patents and overhead at an average cash burn rate	$ 800,000				800,000
Gross proceeds					12,000,000	$ 8,000,000
Additional funds for regulatory approvals, clinical trials, outsourced research and development and commercialization consulting per month					1,100,000
Warrant to purchase shares of common stock [Member]
Stock Issued During Period, Value, Stock Options Exercised					$ 350,000