Earnings Per Share (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Numerator:
Net loss	$ (8,576,379)	$ (6,583,102)	$ (31,900,000)	$ (27,500,000)	$ (47,000,000)
Denominator:
Weighted average number of common shares outstanding (in shares)	48,566,794	23,437,600