Description of Business - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended		12 Months Ended
	Jun. 25, 2013	Feb. 28, 2014	Jan. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 25, 2013
Subsidiary, Sale of Stock [Line Items]
Reverse stock split of common stock and preferred stock				1-for-32
Common stock, shares issued	5,400,000		2,972,972
Common stock price per share	$ 10.00			$ 0.0001	$ 0.0001		$ 10.00
Preferred stock, shares outstanding	0			0			0
Proceeds from underwritten public offering			$ 55,000,000	$ 56,987,000	$ 46,820,000
Underwriters partially exercised an overallotment option, additional gross proceeds		6,400,000		411,000	387,000	187,000
Proceeds from underwritten public offering after fees and commissions		$ 57,000,000
Over-Allotment Option [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock, shares issued		345,945