Stock Compensation (Details) (USD $)	9 Months Ended
	Sep. 30, 2012
Summary of the company's stock option activity
Outstanding at December 31, 2011, Underlying Shares	2,417,659
Outstanding at December 31, 2011, Weighted Average Exercise Price	$ 11.18
Granted, Underlying Shares	921,790
Granted, weighted average exercise Price	$ 9.19
Exercised, Underlying Shares	(167,341)
Exercised, Weighted Average Exercise Price	$ 7.28
Canceled or expired, Underlying Shares	(731,638)
Canceled or expired, Weighted Average Exercise Price	$ 11.32
Outstanding at September 30, 2012, Underlying Shares	2,440,470
Outstanding at September 30, 2012,Weighted Average Exercise Price	$ 10.65
Outstanding at September 30, 2012, Weighted Average Remaining Contractual Term	8 years 4 days
Outstanding at September 30, 2012, Aggregate Intrinsic Value	$ 14,315,000
Vested at September 30, 2012 and expected to vest, Underlying Shares	2,325,299
Vested at September 30, 2012 and expected to vest, Weighted Average Exercise Price	$ 10.75
Vested at September 30, 2012 and expected to vest, Weighted Average Remaining Contractual Term	7 years 11 months 5 days
Vested at September 30, 2012 and expected to vest, Aggregate Intrinsic Value	13,547,000
Exercisable at September 30, 2012, Underlying Shares	770,611
Exercisable at September 30, 2012, Weighted Average Exercise Price	$ 14.54
Exercisable at September 30, 2012, Weighted Average Remaining Contractual Term	5 years 2 months 12 days
Exercisable at September 30, 2012, Aggregate Intrinsic Value	$ 3,174,000