Stockholders' Equity - Additional Information (Detail) - USD ($)					1 Months Ended	6 Months Ended		12 Months Ended
	Aug. 03, 2016	Jul. 25, 2016	Apr. 27, 2016	Apr. 15, 2016	Feb. 29, 2016	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Nov. 30, 2014
Sale Of Stock [Line Items]
Common stock, shares issued						7,291,841		7,201,774
Proceeds from issuance of common stock, net						$ 358,023	$ 1,266,533
Legal, Accounting and Filing Fees						138,000
Payroll withholdings from employees						$ 99,000	$ 111,000
Common stock for Employee Stock Purchase Plan						34,067	23,288
Unrecognized compensation costs						$ 2,600,000
Weighted average period						1 year 1 month 6 days
Amended and Restated Equity Incentive Plan 2013 [Member]
Sale Of Stock [Line Items]
Increase in number of shares of common stock reserved under the plan			500,000
Aggregate number of shares of common stock reserved under the plan			4,786,425
Award plan expiration year			2026
One-Time Option Exchange Program [Member]
Sale Of Stock [Line Items]
Number of stock options exchanged					703,500
Number of stock options exchanged, outstanding					527,624
Number of stock options exchange percentage					75.00%
Options granted, vesting period					3 years
Replacement stock options exercise price					$ 3.04
Incremental compensation expense during period under option exchange					$ 4,700
Unrecognized compensation costs					$ 141,000
Weighted average period					3 years
MLV Sales Agreement [Member]
Sale Of Stock [Line Items]
Common stock, shares issued						0		1,048,507
Common stock, value of shares issuable									$ 6,600,000
Common stock , weighted average price per share								$ 4.78
Proceeds from issuance of common stock, net								$ 4,900,000
FBR Sales Agreement [Member]
Sale Of Stock [Line Items]
Common stock, shares issued						56,000
Common stock , weighted average price per share						$ 5.45
Proceeds from issuance of common stock, net						$ 296,000
Common stock, shares issuable				649,074
Subsequent Event [Member] | July 2016 Financing [Member]
Sale Of Stock [Line Items]
Common stock, shares issued		1,804,512
Purchase price of common stock		$ 2.49375
Warrants exercisable, stock issued		0.75
Warrant exercise price per share		$ 2.41
Warrants expiration period		5 years 6 months
Aggregate gross proceeds from sale of common stock and warrants		$ 4,500,000
Aggregate net proceeds from sale of common stock and warrants		$ 3,900,000
Subsequent Event [Member] | August 2016 Financing [Member]
Sale Of Stock [Line Items]
Common stock, shares issued	3,244,120
Purchase price of common stock	$ 3.0825
Warrants exercisable, stock issued	0.5
Warrant exercise price per share	$ 3.03
Warrants expiration period	5 years 6 months
Aggregate gross proceeds from sale of common stock and warrants	$ 10,000,000
Aggregate net proceeds from sale of common stock and warrants	$ 8,900,000