CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net loss	$ (68,881)	$ (96,853)	$ (111,377)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	830	1,580	1,609
Accretion and amortization on investments, net	2,184	4,422	3,568
Accretion of discount on long-term debt		51
Loss on debt extinguishment		1,664
(Gain) loss on sale/retirement of property and equipment	(142)	5	75
Loss on impairment of excess equipment	271	874
Loss on sale of marketable securities		2
Issuance of common stock in connection with acquired in-process research technology		594	27,500
Issuance of common stock in exchange for services by non-employees	183	744	8,673
Stock-based compensation for employees and directors	5,311	15,249	13,718
Amortization related to 401(k) contributions	726	709	647
Loss on equity method investment		503	2,347
Unrealized gain on fair value of derivatives	(13)	(643)	(190)
Changes in assets and liabilities:
Interest and other receivables	646	401	(479)
Prepaid assets	1,311	4,085	2,866
Deposits and other assets	112	(658)	(45)
Accounts payable	449	(482)	1,288
Accrued compensation and benefits	3,548	944	5,401
Accrued restructuring charges	(1,758)	3,730
Accrued liabilities	(92)	1,038	803
Deferred revenue		(350)	(700)
Translation adjustment	169	(1)	4
Net cash used in operating activities	(55,146)	(62,392)	(44,292)
Cash flows from investing activities:
Restricted cash transfer	(1)	(1)	(1)
Loan to related party			(1,500)
Investment in licensee, net			(23)
Purchases of property and equipment	(862)	(612)	(836)
Proceeds from sale of property and equipment	170		2
Purchases of marketable securities	(79,369)	(144,890)	(183,414)
Proceeds from sales of marketable securities		809
Proceeds from maturities of marketable securities	141,016	176,832	137,320
Proceeds from sale of investment in licensees		1
Net cash provided by (used in) investing activities	60,954	32,139	(48,452)
Cash flows from financing activities:
Proceeds from issuance of long-term debt		6,422
Repayment of long-term debt		(6,422)
Distribution to TA Therapeutics, Ltd. shareholder			(6)
Proceeds from issuance of common stock and warrants, net of issuance costs	150	386	104,121
Net cash provided by financing activities	150	386	104,115
Net increase (decrease) in cash and cash equivalents	5,958	(29,867)	11,371
Cash and cash equivalents, at beginning of year	16,105	45,972	34,601
Cash and cash equivalents, at end of year	22,063	16,105	45,972
Supplemental disclosure of cash flow information:
Cash paid for interest		$ 37