Stockholders' Equity - Summary of Purchase and Sale of Common Stock (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity [Abstract]
Shares of common stock purchased	56,325	1,400	5,900
Aggregate purchase price of shares purchased	$ 2,226,675	$ 52,961	$ 158,060
Shares of common stock sold	83,961	9,729	11,719
Aggregate sale price of shares sold	$ 3,380,448	$ 53,962	$ 158,060