Subsequent Events - Additional Information (Detail) (USD $)			1 Months Ended				9 Months Ended	1 Months Ended				1 Months Ended			1 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Nov. 02, 2012 Subsequent Event Minimum	Nov. 02, 2012 Subsequent Event Purchase Agreement	Nov. 05, 2012 Subsequent Event Lincoln Park Capital Fund, LLC	Nov. 08, 2012 Subsequent Event Lincoln Park Capital Fund, LLC	Nov. 08, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Maximum	Nov. 05, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Scenario One Maximum	Nov. 05, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Scenario One Minimum	Nov. 05, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Scenario Two Minimum	Nov. 02, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Purchase Agreement and Registration Right Agreement	Nov. 02, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Purchase Agreement and Registration Right Agreement Maximum	Nov. 08, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Purchase Agreement	Nov. 05, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Purchase Agreement	Nov. 05, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Purchase Agreement Maximum	Nov. 05, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Regular purchases Maximum	Nov. 05, 2012 Subsequent Event Lincoln Park Capital Fund, LLC Depending upon the closing sale price Maximum
Subsequent Event [Line Items]
Purchase agreement and registration rights agreement											$ 15,000,000			$ 1,500,000
Value of common stock to be sold under the agreement					16,500,000
Common stock to be sold							452,055									100,000	300,000
Agreement expiration period					30 months
Common stock, per share			$ 0.7739						$ 0.75	$ 0.45
Common stock future funding, business days								12 days
Common stock issued	23,048,488	23,048,488				226,027							100,000
Gross proceed from sale of common stock													$ 50,000
Percentage of outstanding share of common stock to be sold												9.99%			4.99%
Description of market value out standing common stock				An amount based on one-third of the market value of our outstanding common stock held by non-affiliates.