Consolidated Statements of Stockholders' Equity (Unaudited) (USD $) In Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Gain	Treasury Stock
Balance, value at Dec. 31, 2012	$ 266,678	$ 512	$ 1,166,605	$ (899,832)	$ 23	$ (630)
Balance, shares at Dec. 31, 2012		512,375
Stock-based compensation	3,978	0	3,978	0	0	0
Issuance of common stock under Equity Incentive Plans, shares		1,597
Issuance of common stock under Equity Incentive Plans, value	347	2	345	0	0	0
Repurchase of common stock	(873)	0	0	0	0	(873)
Net loss	(55,054)	0	0	(55,054)	0	0
Unrealized gain on investments	8	0	0	0	8	0
Balance, value at Jun. 30, 2013	215,084	514	1,170,928	(954,886)	31	(1,503)
Balance, shares at Jun. 30, 2013		513,972
Balance, value at Dec. 31, 2013	170,163	514	1,175,108	(1,003,958)	2	(1,503)
Balance, shares at Dec. 31, 2013		514,349
Stock-based compensation	4,090	0	4,090	0	0	0
Issuance of common stock under Equity Incentive Plans, shares		1,598
Issuance of common stock under Equity Incentive Plans, value	162	2	160	0	0	0
Repurchase of common stock	(887)	0	0	0	0	(887)
Net loss	(56,863)	0	0	(56,863)	0	0
Unrealized gain on investments	3	0	0	0	3	0
Balance, value at Jun. 30, 2014	$ 116,668	$ 516	$ 1,179,358	$ (1,060,821)	$ 5	$ (2,390)
Balance, shares at Jun. 30, 2014		515,947