Changes in Non-Vested Shares of Restricted Common Stock (Detail) (Restricted Stock, USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Restricted Stock
Weighted Average Grant Date Fair Value per share
Nonvested restricted common stock, beginning balance	$ 0.60		$ 0.83
Shares Vested	$ 0.42	[1]	$ 0.83	[1]
Shares granted	$ 0.31		$ 0.62
Shares forfeited			$ 0.73
Nonvested restricted common stock, ending balance	$ 0.44		$ 0.60
Number of shares
Beginning nonvested shares	2,315,040		316,267
Shares vested	(1,950,102)	[1]	(316,267)	[1]
Shares granted	3,210,244		2,725,996
Shares forfeited			(410,956)
Ending nonvested shares	3,575,182		2,315,040

[1] Includes shares awarded to four independent directors that were not re-nominated to the Board and resigned following the certification of the election of new Board on August 6, 2012.