Debt (Tables)

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Convertible Debt

At September 30, 2018 and December 31, 2017, the net carrying value of the debt and the remaining unamortized debt discounts and debt issuance costs were as follows (in thousands):

	September 30, 2018		December 31, 2017
Face amount of the 2019 Notes (non-current due December 2019)	$	68,660	$	143,750
Face amount of the 2021 Loan (current due June 2021)	25,000		—
Face amount of the 2023 Notes (non-current due May 2023)	75,090		—
	$	168,750	$	143,750
Less unamortized discounts and debt issuance costs	26,800		22,773
Total Carrying Value, Net	$	141,950	$	120,977

Schedule of Debt Expense

For the nine months ended September 30, 2018 and 2017, the Company recorded the following expenses in relation to the debt (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Interest expense of the 2019 Notes (1)	$	644	$	1,348	$	2,870	$	4,043
Interest expense of the 2021 Loan	659		—		800		—
Interest expense of the 2023 Notes (1)	889		—		1,523		—
Debt partial extinguishment of 2019 Notes	—		—		2,467		—
Debt discount amortization of the 2019 Notes (1)	1,192		2,193		5,102		6,376
Debt discount amortization of the 2021 Loan	22		—		36		—
Debt discount amortization of the 2023 Notes (1)	717		—		1,215		—
Debt financing amortization of the 2019 Notes (1)	130		239		576		695
Debt financing amortization of the 2021 Loan	30		—		47		—
Debt financing amortization of the 2023 Notes (1)	62		—		104		—
Interest expense	$	4,345	$	3,780	$	14,740	$	11,114

(1) Included within "Interest and other expense, net" on the Condensed Consolidated Statements of Operations, offset by interest income and capitalized interest, as disclosed in Note 6.