Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Entity incorporated year	Oct. 31, 2010
Entity incorporated state name	State of Delaware
Accumulated deficit	$ 227,683	$ 174,191
Cash, cash equivalents and investments	$ 175,174