Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets
Cash and cash equivalents	$ 56,525	$ 49,172
Trade accounts receivable, net	4,913	4,474
Inventory, net	16,251	18,293
Prepaid expenses and other current assets	2,210	2,251
Total current assets	79,899	74,190
Property and equipment, net	14,590	15,434
Other assets	6,151	4,644
Total assets	100,640	94,268
Liabilities and stockholders' equity
Accounts payable	5,168	5,580
Accrued expenses	11,093	9,439
Accrued compensation	3,805	3,604
Revolving credit facility	5,081	3,449
Long-term debt, current portion	9,758	3,519
Deferred revenue, current portion	8,462	9,973
Total current liabilities	43,367	35,564
Long-term debt, less current portion	42,070	19,934
Deferred revenue, less current portion	0	9,376
Other long-term liabilities	5,891	660
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value; 100,000 shares authorized at December 31, 2011 and 2010, respectively; 65,369 and 34,017 shares issued and outstanding at December 31, 2011 and 2010, respectively.	65	34
Additional paid-in capital	291,252	226,802
Accumulated deficit	(282,005)	(198,102)
Total stockholders' equity	9,312	28,734
Total liabilities and stockholders' equity	$ 100,640	$ 94,268