CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 22,063	$ 16,105
Restricted cash	794	793
Current portion of marketable securities	73,472	105,208
Interest and other receivables	752	1,398
Prepaid assets	1,336	2,121
Total current assets	98,417	125,625
Noncurrent portion of marketable securities		32,133
Property and equipment, net	974	1,241
Deposits and other assets	410	1,048
Assets	99,801	160,047
Current liabilities:
Accounts payable	3,429	2,980
Accrued compensation and benefits	5,216	3,029
Accrued restructuring charges	1,972	3,730
Accrued liabilities	3,480	3,641
Fair value of derivatives	51	64
Total current liabilities	14,148	13,444
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value; 3,000,000 shares authorized; no shares issued and outstanding at December 31, 2012 and 2011
Common stock, $0.001 par value; 300,000,000 and 200,000,000 shares authorized; 130,242,695 and 131,443,148 shares issued and outstanding; at December 31, 2012 and 2011, respectively	130	131
Additional paid-in capital	939,867	932,066
Accumulated deficit	(854,384)	(785,503)
Accumulated other comprehensive income (loss)	40	(91)
Total stockholders' equity	85,653	146,603
Liabilities and Stockholders' Equity	$ 99,801	$ 160,047