Stockholders' Equity (Detail) (USD $) In Millions, except Share data, unless otherwise specified				9 Months Ended
	Sep. 30, 2012	May 23, 2012	Dec. 31, 2011	Sep. 30, 2012 Purchase Agreementwith LPC [Member] Minimum [Member]	Sep. 30, 2012 Purchase Agreementwith LPC [Member] Maximum [Member]	Sep. 30, 2012 Purchase Agreementwith LPC [Member]	Oct. 13, 2011 Purchase Agreementwith LPC [Member]	Oct. 07, 2011 Purchase Agreementwith LPC [Member]	May 21, 2012 Shelf Registration [Member]
Common Stock, Shares Authorized	24,000,000	24,000,000	24,000,000
Common Stock And Preferred Stock Shares Authorized	24,100,000
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)						$ 10.0		$ 10.0	$ 50.0
Stock Purchase Agreement Period In Force						30 months
Stock Purchase Agreement Number of Shares Registered							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
Deferred Costs, Noncurrent (in Dollars)						$ 0.1