Equity Incentive Plans (Details 2) (Restricted Stock and Restricted Stock Units [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restricted Stock and Restricted Stock Units [Member]
Summary of nonvested restricted stock and restricted stock units activity
Number of Shares Nonvested Beginning Balance	1,910	1,441	1,240
Number of Shares, Granted		1,003	875
Number of Shares, Vested	(840)	(512)	(634)
Number of Shares, Forfeited or Cancelled	(55)	(22)	(40)
Number of Shares Nonvested Ending Balance	1,015	1,910	1,441
Weighted-Average Grant Date Fair Value Beginning Balance	$ 2.81	$ 4.43	$ 7.04
Weighted-Average Grant Date Fair Value, Granted		$ 1.78	$ 2.50
Weighted-Average Grant Date Fair Value, Vested	$ 3.37	$ 5.28	$ 6.67
Weighted-Average Grant Date Fair Value, Forfeited or Cancelled	$ 1.97	$ 3.69	$ 7.61
Weighted-Average Grant Date Fair Value Ending Balance	$ 2.43	$ 2.81	$ 4.43