CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net loss	$ (29,098)	$ (53,018)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	357	658
Accretion and amortization on investments, net	948	1,806
Gain on sales of property and equipment, net	(759)	(32)
Loss on write-downs of property and equipment	200
Stock-based compensation for services by non-employees	136	152
Stock-based compensation for employees and directors	3,456	4,016
Amortization related to 401(k) contributions	449	336
Unrealized loss on derivatives	207	10
Changes in assets and liabilities:
Other current and noncurrent assets	904	1,941
Other current liabilities	(6,679)	(768)
Translation adjustment		169
Net cash used in operating activities	(29,879)	(44,730)
Cash flows from investing activities:
Restricted cash transfer	(1)	(1)
Purchases of property and equipment	(56)	(854)
Proceeds from sales of property and equipment	1,116	38
Purchases of marketable securities	(57,446)	(54,905)
Proceeds from maturities of marketable securities	73,301	100,275
Net cash provided by investing activities	16,914	44,553
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs	493	80
Net cash provided by financing activities	493	80
Net decrease in cash and cash equivalents	(12,472)	(97)
Cash and cash equivalents at the beginning of the period	22,063	16,105
Cash and cash equivalents at the end of the period	$ 9,591	$ 16,008