Series C Convertible Preferred Stock (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2011 Series C Convertible Preferred Stock	Dec. 31, 2012 Series C Convertible Preferred Stock
Class of Stock [Line Items]
Series C Preferred Stock issued March 31, 2011			7,000	5,444
Preferred stock principal paid in cash			(778)	(2,334)
Preferred stock principal paid in common stock	600,309	672,593	(778)	(778)
Balance			5,444	2,332
Balance			$ 61,403	$ 50,098
Preferred stock principal paid in cash			(7,780)	(23,340)
Preferred stock principal paid in common stock	7,780	7,780	(7,780)	(7,780)
Preferred stock accretion of fees and embedded derivative			4,255	3,491
Balance			$ 50,098	$ 22,469