Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 17,352	$ 41,228
Trade accounts receivable, net	6,161	5,643
Inventory, net	12,089	12,886
Prepaid expenses and other current assets	1,772	2,254
Total current assets	37,374	62,011
Property and equipment, net	12,943	13,561
Other assets	4,316	5,114
Total assets	54,633	80,686
Current liabilities:
Accounts payable	2,972	4,592
Accrued expenses	16,145	14,343
Common stock warrant liabilities	12,273	9,493
Accrued compensation	2,901	4,226
Total current liabilities	34,291	32,654
Long-term debt, less current portion	28,719	28,481
Other long-term liabilities	5,512	5,078
Commitments and contingencies
Stockholders' equity:
Common stock	108	101
Additional paid-in capital	360,634	343,763
Accumulated deficit	(374,631)	(329,391)
Total stockholders’ (deficit) equity	(13,889)	14,473
Total liabilities and stockholders’ equity	$ 54,633	$ 80,686