Summary of Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	Dec. 31, 2016 USD ($) Segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Impairment of long-lived assets		$ 0
Number of reporting unit | Segment	1
Interest charges or penalties related to unrecognized tax benefits		0	$ 0	$ 0
Property and Equipment | Lab Equipment
Summary Of Significant Accounting Policies [Line Items]
Amount received for de minimis consideration	$ 200,000	$ 200,000