Convertible Senior Notes Due 2017 (Tables)

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Interest Expense on Convertible Notes

Interest expense on the Convertible Notes consisted of the following:

	Years Ended December 31,
	2014		2013		2012
Coupon interest expense	$	6,792	$	6,793	$	5,322
Non-cash amortization of debt discount		13,737		12,407		8,910
Non-cash amortization of debt issuance costs		1,161		1,049		753
Total	$	21,690	$	20,249	$	14,985