Convertible Notes Long Term Debt and Credit Facility (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Long term debt by current and non current
Convertible senior notes, net of discount	$ 53,231		$ 99,738
Less discount on notes	(2,269)		(6,766)
Less amount reported as current	(53,231)
Capital lease obligations	1,990		1,642
Total long-term debt	1,990		1,642
Convertible senior notes, less current portion	1,022		875
Less current portion of long-term debt	(968)		(767)
Convertible Senior Unsecured Notes (2008 Notes) [Member]
Long term debt by current and non current
Convertible senior notes	55,500		70,500
Convertible senior notes, net of discount	56,610	[1]	69,880	[1]
Convertible Senior Secured Notes (2010 Notes) [Member]
Long term debt by current and non current
Convertible senior notes, net of discount			$ 36,004

[1] The carrying value of the convertible senior notes and senior secured notes is representative of the bifurcated debt components only, while the fair value is based on the market value of the respective notes, which includes the convertible equity component