Convertible Notes, Long-Term Debt and Credit Facility (Convertible Notes and Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Components of convertible notes and long-term debt
Capital lease obligations	$ 1,784	$ 1,642
Debt and Capital Lease Obligations	26,784	1,642
Less amount reported as current	(4,329)	(767)
Long-term debt, less current portion	22,455	875
Convertible senior notes [Member]
Components of convertible notes and long-term debt
Long-term debt, gross	5,188
Less discount on notes	(55)	(6,766)
Long term debt, net	5,133	99,738
Less amount reported as current	(5,133)	0
Long term debt, less current portion	0	99,738
Term loan [Member]
Components of convertible notes and long-term debt
Long term debt, net	25,000
Convertible senior unsecured notes (2008 Notes) [Member] | Convertible senior notes [Member]
Components of convertible notes and long-term debt
Long-term debt, gross	5,188	70,500
Convertible senior secured notes (2010 Notes) [Member] | Convertible senior notes [Member]
Components of convertible notes and long-term debt
Long-term debt, gross	0	36,004
Term Loan [Member] | Term loan [Member]
Components of convertible notes and long-term debt
Long-term debt, gross	$ 25,000	$ 0