Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	9 Months Ended
	Sep. 30, 2017 USD ($) $ / shares	Sep. 30, 2017 USD ($) Reporting_Unit Segment $ / shares
Significant Accounting Policies [Line Items]
Number of operating segments | Segment		1
Number of reporting units | Reporting_Unit		1
Estimated average market capitalization		$ 36,200,000
Carrying value of the reporting unit		$ 75,430,244
Control premium percentage		35.00%
Goodwill impairment charges	$ 26,600,000	$ 26,600,000
Weighted Average [Member]
Significant Accounting Policies [Line Items]
Initial conversion price | $ / shares	$ 2.31	$ 2.31
PharmAthene [Member]
Significant Accounting Policies [Line Items]
Income tax expense recoverable		$ 5,100,000