Debt and Credit Facilities (Tables)

9 Months Ended

Sep. 30, 2018

Debt Instrument [Line Items]

Schedule of carrying value of the Notes

The carrying value of the Notes is as follows (in thousands):

	September 30, 2018			December 31, 2017
Principal amount	$	46,000		$	46,000
Unamortized debt discount - equity component	(7,135		)	(8,144		)
Unamortized debt discount - initial purchaser	(2,130		)	(2,431		)
Unamortized transaction costs	(336		)	(383		)
Net carrying value	$	36,399		$	35,042

Schedule of convertible debt interest expense

Total interest expense related to the Notes is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Cash interest expense
Coupon interest expense	$	633	$	37	$	1,898	$	37
Non-cash interest expense
Amortization of debt discount - equity component	346		18		1,008		18
Amortization of debt discount - initial purchaser	103		5		301		5
Amortization of transaction costs	16		1		47		1
Total interest expense	$	1,098	$	61	$	3,254	$	61