Earnings (Loss) Per Share - Computation of Basic and Diluted Loss Per Share (Detail) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Numerators for basic and diluted loss per share data:
Net loss from continuing operations	$ (5,195,757)	$ (7,391,602)
Net loss from discontinued operations	(1,708,163)	(423,288)
Net loss attributable to stockholders	$ (6,903,920)	$ (7,814,890)
Denominator for basic and diluted loss per share data-weighted-average shares	48,356,602	29,503,356
Basic and diluted per share data:
Net loss from continuing operations per share	$ (0.11)	$ (0.25)
Net loss from discontinued operations	$ (0.03)	$ (0.01)
Net loss attributable to stockholders	$ (0.14)	$ (0.26)