Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 41,228	$ 56,525
Trade accounts receivable, net	5,643	4,913
Inventory, net	12,886	16,776
Prepaid expenses and other current assets	1,968	2,210
Total current assets	61,725	80,424
Property and equipment, net	13,561	14,590
Other assets	5,400	5,626
Total assets	80,686	100,640
Current liabilities:
Accounts payable	4,592	5,168
Accrued expenses	14,343	10,748
Common stock warrant liabilities	9,493	345
Accrued compensation	4,226	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	32,654	43,367
Long-term debt, less current portion	28,481	42,070
Other long-term liabilities	5,078	5,891
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.001 par value; 200,000 shares authorized at December 31, 2012 and 100,000 shares authorized at December 31, 2011; 100,809 and 65,369 shares issued and outstanding at December 31, 2012 and 2011, respectively.	101	65
Additional paid-in capital	343,763	291,252
Accumulated deficit	(329,391)	(282,005)
Total stockholders’ equity	14,473	9,312
Total liabilities and stockholders’ equity	$ 80,686	$ 100,640