Debt (Tables)

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Convertible Debt

The Convertible Notes consist of the following (in thousands):

	December 31, 2018			December 31, 2017
Liability component
Principal	$	1,164,497		$	1,437,483
Less: note discount and issuance costs	(9,052		)	(51,159		)
Net carrying amount	$	1,155,445		$	1,386,324
Equity component
Temporary equity	$	8,110		$	—
Additional paid-in-capital	127,374			162,869
Total (including temporary equity)	$	135,484		$	162,869

Schedule of Interest Expense Recognized Related to Convertible Notes

The following table includes total interest expense recognized related to the Convertible Notes and 2027 Notes (in thousands):

	Year Ended December 31,
	2018		2017		2016
Contractual interest expense	$	40,151	$	11,406	$	7,187
Amortization of debt issuance costs	4,663		4,050		3,863
Amortization of debt discount	34,228		34,039		33,014
	$	79,042	$	49,495	$	44,064