Summary of Outstanding Warrants Issued (Detail) (USD $)	0 Months Ended		1 Months Ended	3 Months Ended
	Aug. 07, 2013	Aug. 14, 2013	Nov. 30, 2010	Mar. 31, 2014
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Warrants Outstanding				19,933,047
Weighted Average Exercise Price	$ 0.71	$ 1.00	$ 2.65	$ 3.00
Opus loan
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Warrants Outstanding				1,000,000
Weighted Average Exercise Price				$ 0.99
Issue Date				Mar. 31, 2014
Expiration Date				Mar. 31, 2019
2013 Private Placement
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Warrants Outstanding				9,348,471
Weighted Average Exercise Price				$ 1.00
Issue Date				Aug. 14, 2013
Expiration Date				Aug. 14, 2017
Hercules loan
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Warrants Outstanding				992,084
Weighted Average Exercise Price				$ 0.71
Issue Date				Aug. 07, 2013
Expiration Date				Aug. 07, 2018
2010 Private Placement
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Warrants Outstanding				3,691,685
Weighted Average Exercise Price				$ 2.65
Issue Date				Nov. 14, 2010
Expiration Date				Nov. 14, 2015
Hirsch acquisition
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Warrants Outstanding				4,735,427
Weighted Average Exercise Price				$ 3.00
Issue Date				Apr. 30, 2009
Expiration Date				Apr. 30, 2014
Hirsch acquisition variable
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Warrants Outstanding				165,380
Weighted Average Exercise Price				$ 2.79
Issue Date				Apr. 30, 2009
Expiration Date				Apr. 30, 2014