Intangible Assets, Net and Goodwill - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($) Asset	Dec. 31, 2018 USD ($) Asset	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Finite-Lived Intangible Assets [Line Items]
Carrying value of assets	$ 38,872,537	$ 38,872,537	$ 39,209,211
Goodwill impairment loss		490,676	35,919,695
Increase in goodwill from recorded adjustments		$ 490,676	15,573,822
IPR&D [Member]
Finite-Lived Intangible Assets [Line Items]
Number of assets | Asset	3	3
Intangible assets, amount	$ 13,418,967	$ 13,418,967	38,245,871	$ 14,477,019
Carrying value of assets	22,389,000	22,389,000
Impairment of intangible assets	21,389,000	24,450,011
IPR&D [Member] | Oncosyn Cancer Immunotherapy [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, amount	$ 3,061,011	$ 3,061,011
IPR&D [Member] | HepTcell and SparVax-L [Member]
Finite-Lived Intangible Assets [Line Items]
Number of assets | Asset	2	2
IPR&D [Member] | SparVax-L [Member]
Finite-Lived Intangible Assets [Line Items]
Fair value of intangible assets	$ 1,000,000	$ 1,000,000
Minimum [Member] | IPR&D [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives		15 years
Maximum [Member] | IPR&D [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Lives		18 years
Maximum [Member] | IPR&D [Member] | HepTcell [Member]
Finite-Lived Intangible Assets [Line Items]
Percent of fair value of reporting unit excess of carrying value	10.00%	10.00%
Research and Development [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets		$ 83,652	$ 55,185