CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common stock	Additional paid in capital	Accumulated other comprehensive income (loss)	Accumulated deficit
Balance at Dec. 31, 2010	$ 244,542	$ 99	$ 1,000,181	$ 949	$ (756,687)
Balance (in shares) at Dec. 31, 2010		99,394,000
Increase (Decrease) in Stockholders' Equity
Net loss	(84,801)				(84,801)
Change in unrealized gains (losses), net of tax	(1,719)			(1,719)
Issuance of common stock in connection with employee stock plans	3,567	1	3,566
Issuance of common stock in connection with employee stock plans (in shares)		646,000
Warrants exercised (in shares)		3,000
Share-based compensation expense	9,845		9,845
Balance at Dec. 31, 2011	171,434	100	1,013,592	(770)	(841,488)
Balance (in shares) at Dec. 31, 2011		100,043,000
Increase (Decrease) in Stockholders' Equity
Net loss	(65,478)				(65,478)
Change in unrealized gains (losses), net of tax	13,250			13,250
Issuance of common stock in connection with employee stock plans	9,470	2	9,468
Issuance of common stock in connection with employee stock plans (in shares)		1,438,000
2 5/8 percent convertible subordinated notes redemption, equity portion	(12,041)		(12,041)
2 3/4 percent convertible senior notes, equity portion, net of issuance costs	57,560		57,560
Share-based compensation expense	8,571		8,571
Balance at Dec. 31, 2012	182,766	102	1,077,150	12,480	(906,966)
Balance (in shares) at Dec. 31, 2012		101,481,000
Increase (Decrease) in Stockholders' Equity
Net loss	(60,644)				(60,644)
Change in unrealized gains (losses), net of tax	8,600			8,600
Issuance of common stock in connection with employee stock plans	62,958	5	62,953
Issuance of common stock in connection with employee stock plans (in shares)		5,372,000
Issuance of public common stock	173,292	9	173,283
Issuance of public common stock (in shares)		9,618,000
Share-based compensation expense	11,418		11,418
Balance at Dec. 31, 2013	$ 378,390	$ 116	$ 1,324,804	$ 21,080	$ (967,610)
Balance (in shares) at Dec. 31, 2013		116,471,000