Debt (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Interest expense on convertible notes
Interest expense at coupon rate (6.0%)		$ 1,422	$ 2,756	$ 4,347
Non-cash interest in accordance with ASC 470		2,488	5,450	7,133
Total interest expense recognized on convertible debt instruments		$ 3,910	$ 8,206	$ 11,480