Stockholders' Equity (Detail) (USD $) In Millions, except Share data, unless otherwise specified				3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	May 21, 2012 Shelf Registration [Member]	Mar. 31, 2013 Minimum [Member] Purchase Agreementwith LPC [Member]	Mar. 31, 2013 Maximum [Member] Purchase Agreementwith LPC [Member]	Mar. 31, 2013 Purchase Agreementwith LPC [Member]	Oct. 13, 2011 Purchase Agreementwith LPC [Member]	Oct. 07, 2011 Purchase Agreementwith LPC [Member]
Common Stock And Preferred Stock Shares Authorized	24,100,000
Common Stock, Shares Authorized	24,000,000	24,000,000
Common Stock, Par or Stated Value Per Share (in Dollars per share)	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	100,000	100,000
Preferred Stock, Par or Stated Value Per Share (in Dollars per share)	$ 0.01	$ 0.01
Stock Purchase Agreement Authorized Amount (in Dollars)			$ 50.0			$ 10.0		$ 10.0
Stock Purchase Agreement Number of Shares Registered						1,702,836	1,823,577
Stock Issued During Period Shares Issued As Commitment Fees						40,247
Stock Issued During Period Shares Issued As Additional Commitment Fees						80,494
Stock Purchase Agreement Remaining Number of Shares Authorized to be Sold						1,702,836
Sale of Stock Maximum Sale Per Transaction (in Dollars)				$ 0.5	$ 1.5
Stock Purchase Agreement Exchange Cap						1,434,994
Stock Purchase Agreement Exchange Rate Cap						19.99%
Debt Instrument, Convertible, Conversion Price (in Dollars per share)						$ 3.014