Warrants (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Weighted-average assumptions for used for valuing warrants
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Shares underlying warrants classified as liabilities	4,824,827	4,824,827	4,824,827	4,824,827
Market value of stock at beginning of year			$ 4.50	$ 12.72
Market value of stock at end of period	$ 3.78	$ 8.58	$ 3.78	$ 8.58
Maximum [Member]
Weighted-average assumptions for used for valuing warrants
Risk-free interest rate	0.30%	1.30%	0.30%	1.30%
Expected lives	2 years 2 months 12 days	3 years 4 months 24 days	2 years 2 months 12 days	3 years 4 months 24 days
Expected volatility	90.50%	88.50%	90.50%	88.50%
Minimum [Member]
Weighted-average assumptions for used for valuing warrants
Risk-free interest rate	0.20%	0.50%	0.20%	0.50%
Expected lives	6 months	1 year 6 months	6 months	1 year 6 months
Expected volatility	71.80%	55.30%	71.80%	55.30%