Preferred Stock, Common Stock and Stockholders' Equity - Common Stock - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Feb. 29, 2016	Feb. 22, 2016	Nov. 13, 2014
Sale Of Stock [Line Items]
Common stock, shares outstanding	7,201,774	6,112,091
Shareholders voting power description	Each share of common stock is entitled to one vote. The holders of the common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors of the Company.
Dividends declared on common stock	$ 0
Common stock, shares issued	7,201,774	6,112,091
Proceeds from issuance of common stock, net	$ 5,031,184	$ 42,875
Legal, Accounting and Filing Fees	138,000
Payroll withholdings from employees	$ 170,000
Common stock for Employee Stock Purchase Plan	41,176	7,294
Sales Agreement with MLV & Co. LLC [Member]
Sale Of Stock [Line Items]
Common stock, value of shares issuable					$ 6,600,000
Common stock, shares issued	1,048,507
Common stock , weighted average price per share	$ 4.78
Proceeds from issuance of common stock, net	$ 4,900,000
Aggregate market value of entity common stock held by non affiliates	$ 75,000,000
Sales Agreement with MLV & Co. LLC [Member] | Subsequent Event [Member]
Sale Of Stock [Line Items]
Entity public float, common stock shares			4,100,000
Entity public float			$ 14,600,000
Common stock, closing price				$ 3.57
One third value of entity public float			$ 4,800,000