Convertible Senior Notes Due 2017 (Tables)

6 Months Ended

Jun. 30, 2014

Debt Disclosure [Abstract]

Interest Expense on Convertible Notes

Interest expense on the Convertible Notes consisted of the following:

	Three Months Ended June 30,				Six Months Ended June 30,
	2014		2013		2014		2013
Coupon interest expense	$	1,698	$	1,698	$	3,396	$	3,396
Non-cash amortization of debt discount		3,355		3,028		6,611		5,969
Non-cash amortization of debt issuance costs		283		256		559		505
Total	$	5,336	$	4,982	$	10,566	$	9,870