Debt Obligations - (Tables)

6 Months Ended

Jun. 30, 2016

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:

	June 30, 2016		December 31, 2015
Convertible senior notes	$	60,000	$	60,000
Less: Unamortized interest discount	100		1,893
Less: Unamortized debt issuance costs	15		261
Net carrying value of convertible senior notes	$	59,885	$	57,846

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 and six months endedJune 30, 2016 and June 30, 2015:

	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Contractual interest coupon	$	563	$	563	$	1,125	$	1,125
Amortization of interest discount	899		815		1,793		1,626
Amortization of debt issuance costs	123		104		246		207
Total interest cost recognized	$	1,585	$	1,482	$	3,164	$	2,958