Borrowings (Tables)

6 Months Ended

Jun. 30, 2018

Debt Disclosure [Abstract]

Summary of Borrowings

Borrowings consist of the following (in thousands):

	June 30, 2018			December 31, 2017
Facility Financing Obligation (2019 Notes and Tranche B notes)
Principal amount	$	39,000		$	54,407
Unamortized debt issuance costs and debt discount		(998	)		(1,662	)
Net carrying amount	$	38,002		$	52,745
Senior Convertible Notes (2021 Notes)
Principal amount	$	18,690		$	23,690
Unamortized premium		471			721
Net carrying amount	$	19,161		$	24,411
Note payable to related party - net carrying amount	$	72,196		$	79,666
Total debt - net carrying amount	$	129,359		$	156,822

Accretion of Debt Issuance Cost and Debt Discount

Accretion of debt issuance cost and debt discount during the three and six months ended June 30, 2018 and 2017, are as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Accretion expense - debt issuance cost	$	10	$	24	$	17	$	32
Accretion expense - debt discount	$	385	$	686	$	698	$	1,133

Schedule of Amortization of Premium and Accretion of Debt Issuance Costs

Amortization of the premium and accretion of debt issuance costs related to the 2021 and 2018 notes for the three and six months ended June 30, 2018 and 2017 are as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Amortization of debt premium	$	40	$	61	$	83	$	120
Accretion expense - debt issuance cost		1	$	68	$	1	$	134