Debt Obligations (Tables)

12 Months Ended

Dec. 31, 2012

Debt Obligations [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

The following table reflects the net carrying value of the Notes as of December 31, 2012:

	December 31, 2012
Convertible senior notes	$	60,000
Less: Unamortized interest discount	10,990
Net carrying value of convertible senior notes	$	49,010

Interest cost recognized on the convertible senior notes [Table Text Block]

The following table presents the amount of interest cost recognized relating to the Notes during the twelve months ended December 31, 2012.

	December 31, 2012
Contractual interest coupon	$	2,251
Amortization of interest discount	2,486
Amortization of debt issuance costs	250
Total interest cost recognized	$	4,987