Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Operating activities
Net loss	$ (16,645)	$ (27,929)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation	169	181
Amortization of debt issuance costs and accretion of debt discount	380	40
Amortization of investment premiums	156	457
Stock-based compensation expense	1,214	1,424
Loss on disposal of property and equipment	71
Changes in operating assets and liabilities:
Trade receivables	458	(310)
Receivable from collaborative partner	481	(15)
Inventories	586	(113)
Prepaid expenses and other current assets	35	75
Other assets	(101)
Accounts payable	(614)	171
Accrued compensation	(1,039)	(301)
Accrued research and development	(73)	289
Accrued interest payable on long term obligations	3,811	4,107
Deferred product revenue, net	(427)	254
Deferred collaborative revenue	(3,611)	(3,591)
Deferred rent	(99)	(83)
Other accrued expenses	(1,093)	939
Net cash used in operating activities	(15,341)	(24,405)
Investing activities
Purchases of short-term investments	(13,055)	(3,582)
Proceeds from maturities of short-term investments	22,869	20,500
Proceeds from sales of short-term investments		3,561
Purchases of property and equipment	(26)	(87)
Net cash provided by investing activities	9,788	20,392
Financing activities
Proceeds from issuance of common stock, net	2,919	163
Net cash provided by financing activities	2,919	163
Net decrease in cash and cash equivalents	(2,634)	(3,850)
Cash and cash equivalents, beginning of period	9,148	8,705
Cash and cash equivalents, end of period	6,514	4,855
Supplemental cash flow information
Cash paid for interest	$ 1,468	$ 352