Debt Obligations - (Tables)

3 Months Ended

Mar. 31, 2014

Debt Obligations [Abstract]

Schedule of carrying value of convertible senior notes [Table Text Block]

The following table reflects the net carrying value of the Notes:

	March 31, 2014		December 31, 2013
Convertible senior notes	$	60,000	$	60,000
Less: Unamortized interest discount	7,514		8,249
Net carrying value of convertible senior notes	$	52,486	$	51,751

Schedule of interest cost recognized on convertible senior notes [Table Text Block]

The following table presents the amount of interest cost recognized relating to the Notes during the three months endedMarch 31, 2014 and March 31, 2013.

	Three Months Ended March 31,
	2014		2013
Contractual interest coupon	$	562	$	562
Amortization of interest discount	735		667
Amortization of debt issuance costs	87		72
Total interest cost recognized	$	1,384	$	1,301