Convertible Subordinated Debt (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011
Convertible Subordinated Debt
Common stock issued in exchange of convertible subordinated notes	7,614,000
Principal amount of the convertible subordinated notes	$ 116,600
Interest rate of convertible subordinated notes	2.25%	2.25%
Due date of convertible subordinated notes	Oct. 15, 2011
Unamortized discount	1,200	1,200
Principal amount repaid		78,000
Interest expense	$ 808	$ 808