Convertible Debt (Tables)

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

The net carrying amount of the liability component of the Notes consists of the following:

	As of December 31,
	2014			2013
Total convertible senior notes - par	$	169,400		$	400,000
Unamortized discount	(22,627		)	(79,685		)
	$	146,773		$	320,315

Interest Expense Associated with Convertible Notes

	Year Ended December 31,
	2014		2013		2012
Contractual coupon interest rate	$	5,036	$	7,230	$	7,503
Amortization of discount and note issuance costs	17,821		22,980		21,623
	$	22,857	$	30,210	$	29,126