Convertible Senior Notes (Tables)

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

The Notes consisted of the following:

	As of September 30, 2018
Liability:
Principal	$	143,750
Less: debt discount, net of amortization	(27,919		)
Less: debt issuance costs, net of amortization	(3,701		)
Net carrying amount of the Notes	$	112,130
Stockholders' equity:
Allocated value of the conversion feature	$	28,916
Less: debt issuance costs	(965		)
Additional paid-in capital	$	27,951

The following table sets forth total interest expense recognized related to the Notes for the period presented:

	Three Months Ended September 30, 2018
Amortization of debt discount	$	997
Amortization of debt issuance costs	131
Total amortization of debt issuance costs and accretion of equity portion	1,128
Contractual interest expense	482
Total interest expense related to the Notes	$	1,610
Effective interest rate of the liability component	7.10		%