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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Related Party - Additional Information (Detail) - Amunix Inc. [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Additional consideration, milestone payments				$ 30.0
Operating expenses from related party transaction	$ 0.6	$ 0.8	$ 0.8
Due to related party	$ 0.1	$ 0.1
Preferred stock [Member]
Related Party Transaction [Line Items]
Ownership percentage				10.00%
Common Stock [Member] \| Maximum [Member]
Related Party Transaction [Line Items]
Ownership percentage	5.00%