Organization and Basis of Presentation - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Organization And Basis Of Presentation [Abstract]
Month and year of incorporation	2007-01
Cash and cash equivalents	$ 10,412,968	$ 9,007,071	$ 10,379,882	$ 8,691,155