Stockholders' Equity - Common and Preferred Shares - Additional Information (Detail) (USD $)	0 Months Ended				3 Months Ended	6 Months Ended								0 Months Ended		3 Months Ended			0 Months Ended	3 Months Ended	0 Months Ended			6 Months Ended	12 Months Ended	0 Months Ended	6 Months Ended		6 Months Ended		6 Months Ended	12 Months Ended	0 Months Ended		6 Months Ended			12 Months Ended					6 Months Ended		6 Months Ended
	May 28, 2014	Feb. 18, 2014	Sep. 23, 2013	Apr. 16, 2013	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	May 28, 2014	Feb. 18, 2014	Dec. 31, 2013	Apr. 16, 2013	Jun. 30, 2014 2005 Plan [Member] Participant	Jun. 30, 2014 Placement Agent and Related Persons [Member]	Sep. 23, 2013 Series A Preferred Stock [Member]	Apr. 16, 2013 Series A Preferred Stock [Member]	Jun. 30, 2013 Series A Preferred Stock [Member]	Dec. 31, 2013 Series A Preferred Stock [Member]	Sep. 30, 2013 Series A Preferred Stock [Member]	Sep. 23, 2013 Series B Preferred Stock [Member]	Sep. 30, 2013 Series B Preferred Stock [Member]	Apr. 16, 2013 Private Placement Series A Warrants [Member]	Jun. 30, 2014 Private Placement Series A Warrants [Member]	Apr. 16, 2013 Private Placement Series A Warrants [Member]	Jun. 30, 2014 Private Placement Series B Warrants [Member]	Dec. 31, 2013 Private Placement Series B Warrants [Member]	Feb. 18, 2014 Public Offering [Member]	Jun. 30, 2014 Public Offering [Member]	Feb. 18, 2014 Public Offering [Member]	Jun. 30, 2014 Common Stock [Member]	Sep. 23, 2013 Common Stock [Member]	Jun. 30, 2014 Common Stock [Member] Private Placement Series B Warrants [Member]	Dec. 31, 2013 Common Stock [Member] Private Placement Series B Warrants [Member]	May 28, 2014 Registered Offering [Member]	May 28, 2014 Registered Offering [Member]	Jun. 30, 2014 Private Placement [Member]	May 28, 2014 Private Placement [Member]	Feb. 18, 2014 Private Placement [Member]	Dec. 31, 2013 Private Placement [Member] Series A Preferred Stock [Member]	Dec. 31, 2013 Private Placement [Member] Series B Preferred Stock [Member]	Feb. 18, 2014 Private Placement [Member] Public Offering [Member]	Dec. 31, 2013 Private Placement [Member] Common Stock [Member]	May 28, 2014 Private Placement [Member] Registered Offering [Member]	Jun. 30, 2013 MLV & Co. LLC [Member]	Jun. 30, 2014 MLV & Co. LLC [Member]	Jun. 30, 2014 Lincoln Park Capital Fund, LLC [Member]	Nov. 30, 2011 Lincoln Park Capital Fund, LLC [Member]
Stockholders' Equity - Common and Preferred Shares [Line Items]
Net proceeds from issuance of common stock and warrants	$ 14,822,000	$ 10,860,000
Gross proceeds from issuance of common stock and warrants	16,000,000	12,000,000
Share price of common stock and warrants issued																												$ 2.05						$ 2.9625
Number of warrants issued for each unit issued																												0.5						0.5
Common stock issued during period															5,000				5,800							5,853,657					350,000	270,390	5,400,847										422,000
Exercise of warrants, shares of Company's common stock converted						1,054,625																	1,377,412	1,377,412				2,926,829	2,452,431					2,700,424						292,682		216,033
Term of warrants	5 years 3 months 18 days	5 years				5 years
Exercise price						2.24		2.90	2.75				2.80									3.40	3.40	3.40												3.7031	2.56
Percentage of warrants owned								4.99%	9.99%
Increase in percentage of warrants owned	9.99%
Number of warrant exercised						1,054,625																													2,452,431
Proceeds from warrant exercises						9,512,000																		1,119,000	864,000		2,900,000		5,493,000
Gross proceeds			5,800,000	5,000,000
Net proceeds			4,905,000	4,192,000										2,103,000
Number of common stock issued upon conversion											1,377,412																			2,452,431									2,452,431		605,422
Number of preferred stock converted																																						2,198	5,800
Number of preferred stock outstanding						0				0				2,802			0	2,802																					0
Redeemable value of outstanding balance														2,802,000				2,802,000
Exercisable period of warrants						5 years															5 years			2 years
Purchase of common stock at closing						147,145																	82,645
Warrant exercised																								350,000	270,390
Non-cash deemed dividend to preferred stock					2,481,000		2,481,000									2,480,000				2,310,000
Proceeds from issuance of common stock, net of issuance costs						25,681,000	1,936,000																																				1,936,000
Issuance of common stock						20,702,000				5,586,000																																		0
Value of purchase agreement for the sale with Lincoln Park Capital Fund, LLC																																														20,000,000
Purchase agreement date of expiration																																													January 11, 2015
Minimum purchase price per share																																														$ 6.00
Additional value of purchase agreement for the sale with Lincoln Park Capital Fund, LLC																																														17,400,000
Value of warrants recorded on the Company's balance sheet						0				0
Warrant closing date						Jul. 20, 2014
Maximum number of shares acquired for the award of options, restricted stock and stock appreciation												833,333
Maximum number of shares granted to any one participant in any fiscal year												200,000
Number of participant												1
Weighted average period for recognizing unrecognized compensation cost as expense						3 years
Unrecognized compensation cost related to stock option awards						$ 568,000