Net Loss Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net Loss (Numerator_ [Abstract]
Net loss basic and diluted	$ (12,263)	$ (10,720)	$ (23,521)	$ (23,806)
Weighted Average Common Shares (Denominator) Abstract
Shares outstanding, basic and diluted (in shares)	51,481	33,798	50,802	33,779
Per share amount [Abstract]
Net loss per share, basic and diluted (in dollars per share)	$ (0.24)	$ (0.32)	$ (0.46)	$ (0.70)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unvested restricted stock (in shares)		33,627		33,627
Weighted Average Number (in shares)	6,340	6,301	6,036	6,096
Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted Average Number (in shares)	6,340	6,227	6,036	6,011
Weighted Average Exercise Price (in dollars per share)	$ 11.62	$ 12.26	$ 11.97	$ 12.35
Unvested restricted stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted Average Number (in shares)	0	74	0	85