Long-term Debt (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Schedule of convertible debt

The following table summarizes the carrying value of the long-term convertible debt (in thousands):

	As of December 31,
	2019		2018
2025 Notes
Carrying value	$	107,169	$	98,730
Unamortized debt discount and issuance costs allocated to debt	65,331		73,770
Principal amount	$	172,500	$	172,500
Remaining amortization period (years)	5.8		6.8
2021 Notes
Carrying value	$	123,237	$	122,311
Unamortized issuance costs	1,763		2,689
Principal amount	$	125,000	$	125,000
Remaining amortization period (years)	1.9		2.9