Debt (Tables)

12 Months Ended

Dec. 31, 2014

Debt

Schedule of components of interest expense incurred in connection with the entity's convertible notes

        Interest expense incurred in connection with our convertible notes consisted of the following (in thousands):

	Year Ended December 31,
	2014		2013		2012
Contractual coupon rate of interest	$	2,151	$	2,500	$	2,500
Discount amortization		11,057		11,178		10,487
Interest expense—convertible notes	$	13,208	$	13,678	$	12,987

Schedule of information about carrying amount of convertible notes

        The carrying value of our convertible notes consisted of the following (in thousands):

	As of December 31,
	2014			2013
Principal balance	$	138,750		$	250,000
Discount, net of accumulated amortization of $19,819 and $23,783		(12,336	)		(34,155	)
Carrying amount	$	126,414		$	215,845

Schedule of components of interest expense presented on the entity's consolidated statements of operations

        Details of interest expense presented on our consolidated statements of operations are as follows (in thousands)

	Year Ended December 31,
	2014		2013			2012
Interest expense	$	17,592	$	18,117		$	17,544
Less: interest capitalized		—		(59	)		(905	)
Total interest expense	$	17,592	$	18,058		$	16,639