Debt (Tables)

6 Months Ended

Jun. 30, 2012

Debt [Abstract]

Summary of Long-term debt

	June 30, 2012			December 31, 2011
Convertible notes	$	91,875		$	91,875
Less unamortized debt discount		—			(5,450	)
		91,875			86,425
Less current portion		(91,875	)		(86,425	)
Total long-term debt	$	—		$	—

Additional information regarding convertible notes

	June 30, 2012			December 31, 2011
Principal amount of the liability component	$	91,875		$	91,875
Unamortized discount of liability component		—			(5,450	)
Net carrying amount of liability component		91,875			86,425
Carrying amount of the equity component		23,360			23,360
Remaining amortization period of discount		0 months			6 months
Conversion price	$	21.78		$	21.78
Effective interest rate on liability component		18.41	%		18.41	%
If-converted value in excess of principal amount (a)	$	34,681		$	3,454
If-converted number of shares to be issued (a)		1,156			153

Interest expense on convertible debt instruments

	Three Months Ended June  30,				Six Months Ended June  30,
	2012		2011		2012		2011
Interest expense at coupon rate (6.0%)	$	1,378	$	1,462	$	2,756	$	2,925
Non-cash interest in accordance with ASC 470		2,725		2,322		5,450		4,645
Total interest expense recognized on convertible debt instruments	$	4,103	$	3,784	$	8,206	$	7,570