Common Stock - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Class Of Stock [Line Items]
Common stock, shares authorized		50,000,000	50,000,000	50,000,000
Voting power per share		One
Common stock, dividends declared		$ 0
Secondary Offering [Member]
Class Of Stock [Line Items]
Public offering shares of common stock issued	4,999,999
Proceeds from issuance of common stock in secondary offering, net of issuance costs	$ 80,209,000	$ 80,209,000