Quarterly report pursuant to Section 13 or 15(d)

Capital Structure - Additional Information (Detail)

Capital Structure - Additional Information (Detail) (USD $)	0 Months Ended		1 Months Ended	3 Months Ended
	Mar. 31, 2015	Aug. 01, 2014	Aug. 31, 2014	Mar. 31, 2015	Dec. 31, 2014	Jul. 31, 2014
Class of Stock [Line Items]
Common stock, shares authorized	100,000,000us-gaap_CommonStockSharesAuthorized			100,000,000us-gaap_CommonStockSharesAuthorized	100,000,000us-gaap_CommonStockSharesAuthorized	100,000,000us-gaap_CommonStockSharesAuthorized
Common stock, par value	$ 0.0001			$ 0.0001	$ 0.0001
IPO, closing date				Aug. 01, 2014
Initial public offering, units description				Each unit consisted of one share of common stock, one Class A Warrant to purchase one share of common stock at an exercise price of $4.80 per share and one Class B Warrant to purchase one-half share of common stock at an exercise price of $4.00 per full share (the "Units").
Warrant exercise price per share	$ 7.50			$ 7.50
Common stock units issued upon exercise of option by underwriters				206,410
Net proceeds from initial public offering		$ 35,000,000	$ 35,000,000
Class of warrant purchase percentage	3.00%			3.00%
Warrant expiration date				Aug. 27, 2019
Warrant exercisable period				180 days
Common stock, voting rights				The holders of shares of common stock are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings.
Dividends declared or paid	$ 0us-gaap_Dividends
Number of shares issued on conversion of preferred stock including in-kind dividend payable into common stock		6,861,968us-gaap_ConversionOfStockSharesIssued1
Initial Public Offering [Member]
Class of Stock [Line Items]
Common stock units sold by initial public offering		6,880,333
Public offering price, per unit		$ 6.00
Common stock units issued upon exercise of option by underwriters		880,333
Common Class A [Member] \| Initial Public Offering [Member]
Class of Stock [Line Items]
Warrant exercise price per share		$ 4.80
Common Class B [Member] \| Initial Public Offering [Member]
Class of Stock [Line Items]
Warrant exercise price per share		$ 4.00