Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating activities
Net loss	$ (49,545)	$ (44,516)	$ (21,867)
Adjustments to reconcile net loss to cash (used in) provided by operating activities:
Depreciation	376	343	184
Amortization of debt issuance costs and accretion of debt discount	620	54	123
Amortization of investment premiums	677	520	130
Stock-based compensation	3,426	2,354	2,492
Gain on disposal of property and equipment		2
Changes in operating assets and liabilities:
Restricted cash	(2)	(250)
Trade receivables	(559)	(607)
Receivable from collaboration partner	(437)	613	(678)
Prepaid expenses and other current assets	38	(344)	(310)
Inventories	132	(729)	(58)
Accounts payable	(223)	1,479	(305)
Accrued compensation	(145)	(289)	1,118
Accrued research and development	(300)	(87)	(397)
Accrued license fees		(1,213)	1,213
Accrued interest payable on long-term obligations	8,457	5,306
Deferred product revenue, net	498	577
Deferred collaboration revenue	(7,242)	(7,242)	46,843
Other long-term liabilities	(176)	(123)	114
Other accrued expenses	(703)	1,735	585
Net cash (used in) provided by operating activities	(45,108)	(42,417)	29,187
Investing activities
Purchases of short-term investments	(31,684)	(90,029)	(37,459)
Proceeds from maturities of short-term investments	36,870	72,254	30,496
Proceeds from sales of short-term investments	7,104
Change in restricted cash			40
Purchases of property and equipment	(114)	(415)	(456)
Net cash provided by (used in) investing activities	12,176	(18,190)	(7,379)
Financing activities
Repayment of notes payable		(191)	(2,913)
Proceeds from issuance of long-term obligations	14,820	39,505
Payment of debt issuance costs	(213)	(309)
Proceeds from issuance of warrants	822
Proceeds from issuance of common stock	17,946	612	365
Net cash provided by (used in) financing activities	33,375	39,617	(2,548)
Net increase (decrease) in cash and cash equivalents	443	(20,990)	19,260
Cash and cash equivalents, beginning of period	8,705	29,695	10,435
Cash and cash equivalents, end of period	9,148	8,705	29,695
Supplemental cash flow information
Cash paid for interest	1,325	53	181
Non-cash financing activities
Contingent put option liability	146
Warrants issued in connection with private equity placement and debt financing	$ 7,016