Convertible Senior Notes (Tables)

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

The Notes consisted of the following:

	As of December 31, 2018
Liability
Principal	$	143,750
Less: debt discount, net of amortization	(26,636		)
Less: debt issuance costs, net of amortization	(3,528		)
Net carrying amount of the Notes	$	113,586
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:

	Twelve Months Ended December 31, 2018
Amortization of debt discount	$	2,280
Amortization of debt issuance costs	304
Total amortization of debt issuance costs and accretion of equity portion	2,584
Contractual interest expense	1,097
Total interest expense related to the Notes	$	3,681
Effective interest rate of the Notes	7.25		%