Net Income (Loss) Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Numerator:
Net loss available to common stockholders	$ (6,825)	$ (7,847)	$ (16,507)	$ (15,600)
Denominator:
Weighted average shares outstanding - basic	36,045	35,775	35,818	35,520
Potential common shares - options (treasury stock method)
Weighted average shares outstanding - diluted	36,045	35,775	35,818	35,520
Shares excluded (anti-dilutive)	18	209	25	348
Shares excluded due to an exercise price greater than weighted average stock price for the period	1,483	1,970	1,364	1,848
Net loss per common share:
Basic	$ (0.19)	$ (0.22)	$ (0.46)	$ (0.44)
Diluted	$ (0.19)	$ (0.22)	$ (0.46)	$ (0.44)