Intangible Assets, Net and Goodwill - Schedule of Changes in Carrying Amounts of IPR&D Assets and Goodwill (Detail) - USD ($)	3 Months Ended	12 Months Ended
Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Indefinite Lived Intangible Assets By Major Class [Line Items]
Goodwill Balance, beginning of period			$ 18,758,421
Goodwill, Additions from the mergers		$ 490,676	15,573,822
Goodwill, Foreign currency translation adjustments			1,587,452
Goodwill, Impairment charges		(490,676)	(35,919,695)
Goodwill Balance, end of period	$ 0	0
IPR&D [Member]
Indefinite Lived Intangible Assets By Major Class [Line Items]
IPR&D Balance, beginning of period		38,245,871	14,477,019
IPR&D, Additions from the Mergers			22,389,000
IPR&D, Foreign currency translation adjustments		(376,893)	1,379,852
IPR&D, Impairment charges	(21,389,000)	(24,450,011)
IPR&D Balance, end of period	$ 13,418,967	$ 13,418,967	$ 38,245,871

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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