Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended	6 Months Ended
	Jul. 31, 2015	Jun. 30, 2015	Dec. 31, 2014	Nov. 13, 2014	Nov. 11, 2014
Sale Of Stock [Line Items]
Common stock, shares issued		6,306,130	6,112,091
Proceeds from issuance of common stock, net		$ 1,266,533
Legal, Accounting and Filing Fees		$ 138,000
Common stock, shares outstanding		6,306,130	6,112,091
Payroll withholdings from employees		$ 111,000
Common stock for Employment Stock Purchase Plan		23,288
Unrecognized compensation costs		$ 3,000,000
Weighted average period		1 year 3 months 26 days
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		170,751
Common stock , weighted average price per share		$ 6.99
Proceeds from issuance of common stock, net		$ 1,200,000
Common stock, shares outstanding					2,900,000
Entity public float					$ 20,000,000
Common stock, closing price					$ 6.86
One third value of entity public float					$ 6,600,000
Sales Agreement with MLV & Co. LLC [Member] | Subsequent Event [Member]
Sale Of Stock [Line Items]
Common stock, value of shares issuable	$ 5,200,000
Common stock, shares issued	32,672
Common stock , weighted average price per share	$ 6.17
Proceeds from issuance of common stock, net	$ 195,000