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	2,109	0	2,109	0	0	0
Issuance of common stock under Equity Incentive Plans, shares		1,460
Issuance of common stock under Equity Incentive Plans, value	249	2	247	0	0	0
Repurchase of common stock	(873)	0	0	0	0	(873)
Net loss	(25,974)	0	0	(25,974)	0	0
Unrealized gain on investments	19	0	0	0	19	0
Balance, value at Mar. 31, 2013	242,208	514	1,168,961	(925,806)	42	(1,503)
Balance, shares at Mar. 31, 2013		513,835
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	2,250	0	2,250	0	0	0
Issuance of common stock under Equity Incentive Plans, shares		1,435
Issuance of common stock under Equity Incentive Plans, value	76	2	74	0	0	0
Repurchase of common stock	(887)	0	0	0	0	(887)
Net loss	(30,835)	0	0	(30,835)	0	0
Unrealized gain on investments	8	0	0	0	8	0
Balance, value at Mar. 31, 2014	$ 140,775	$ 516	$ 1,177,432	$ (1,034,793)	$ 10	$ (2,390)
Balance, shares at Mar. 31, 2014		515,784