Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 49,552	$ 56,525
Trade accounts receivable, net	5,504	4,913
Inventory, net	13,705	16,251
Prepaid expenses and other current assets	2,600	2,210
Total current assets	71,361	79,899
Property and equipment, net	13,673	14,590
Other assets	6,273	6,151
Total assets	91,307	100,640
Current liabilities:
Accounts payable	4,876	5,168
Accrued expenses	12,200	10,748
Common stock warrant liabilities	24,915	345
Accrued compensation	3,803	3,805
Revolving credit facility	0	5,081
Long-term debt, current portion	0	9,758
Deferred revenue, current portion	0	8,462
Total current liabilities	45,794	43,367
Long-term debt, less current portion	28,413	42,070
Other long-term liabilities	3,811	5,891
Commitments and contingencies
Stockholders' equity
Common stock	101	65
Additional paid-in capital	341,936	291,252
Accumulated deficit	(328,748)	(282,005)
Total stockholders' equity	13,289	9,312
Total liabilities and stockholders' equity	$ 91,307	$ 100,640