Debt and Other Financing Arrangements (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule of the net carrying amount of debt

The net carrying amount of the liability component of the Notes as of December 31, 2016 and 2015 consists of the following (in thousands):

	December 31, 2016			December 31, 2015
Principal amount	$	253,000		$	253,000
Unamortized debt discount	(12,550		)	(20,417		)
Net carrying amount before unamortized debt issuance costs	240,450			232,583
Unamortized debt issuance costs	(2,015		)	(3,278		)
Net carrying value	$	238,435		$	229,305

Schedule of note interest expense

The following table presents the interest expense recognized related to the Notes for years ended December 31, 2016, 2015 and 2014 (in thousands):

	Year Ended  December 31,		Year Ended  December 31,		Year Ended  December 31,
	2016		2015		2014
Contractual interest expense at 1.5% per annum	$	3,795	$	3,795	$	3,795
Amortization of debt issuance costs	1,263		1,202		1,145
Accretion of debt discount	7,867		7,489		7,129
Total	$	12,925	$	12,486	$	12,069