Business Combination - Schedule of Lists of Various Securities (Detail) - USD ($)	May 04, 2017	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Outstanding PharmAthene common stock		9,078,238	608,499
Outstanding PharmAthene stock options		353,274	60,618
Weighted average per share fair value of PharmAthene stock options, vested and unvested		$ 10.97	$ 128.23
PharmAthene [Member]
Business Acquisition [Line Items]
Outstanding PharmAthene common stock	229,450
Outstanding PharmAthene stock options	4,100
Outstanding PharmAthene stock warrants	155
Per share fair value of PharmAthene common stock	$ 195.00
Weighted average per share fair value of PharmAthene stock options, vested and unvested	7.80
Per share fair value of PharmAthene stock warrants	$ 0.30
Aggregate fair value of consideration	$ 44,757,910
Less fair value of unvested common stock options	(15,173)
Total fair value of consideration	$ 44,742,737

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