Convertible Notes (Tables)

12 Months Ended

Dec. 31, 2013

Debt Disclosure [Abstract]

Schedule of convertible notes

The Company’s convertible notes are shown in the following table.

(Dollars in thousands)	As of December 31, 2013			As of December 31, 2012
1.125% Convertible Senior Notes due 2018	$	138,000		$	—
5% Convertible Senior Notes due 2014	172,500			172,500
Total principal amount of convertible notes	310,500			172,500
Unamortized discount - 2018 Notes	(28,371		)	—
Unamortized discount - 2014 Notes	(8,453		)	(24,944		)
Total unamortized discount	$	(36,824	)	$	(24,944	)
Total convertible notes	$	273,676		$	147,556
Less current portion	164,047			—
Total long-term convertible notes	$	109,629		$	147,556

Schedule of interest expense on notes

Interest expense related to the notes for the years ended December 31, 2013, 2012 and 2011 was as follows:

	Years Ended December 31,
	2013		2012		2011
	(in thousands)
2018 Notes coupon interest at a rate of 1.125%	$	582	$	—	$	—
2018 Notes amortization of discount and debt issuance cost at an additional effective interest rate of 5.5%	$	2,171	—		—
2014 Notes coupon interest at a rate of 5%	8,625		8,625		8,625
2014 Notes amortization of discount at an additional effective interest rate of 11.7%	17,126		14,695		12,622
Total interest expense on convertible notes	$	28,504	$	23,320	$	21,247