Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 26,911	$ 32,003	[1]
Marketable securities	3,009	13,524	[1]
Accounts receivable, net of allowances of $478 and $150 at September 30, 2013 and December 31, 2012, respectively	2,688	7,545	[1]
Inventories	2,101	1,302	[1]
Prepaid expenses and other current assets	1,935	5,395	[1]
Total current assets	36,644	59,769	[1]
Restricted cash	911	1,511	[1]
Non-current marketable securities	1,067	3,623	[1]
Property and equipment, net	13,809	16,650	[1]
Intangible assets, net	10,403	12,934	[1]
Goodwill	3,241	3,241	[1]
Other non-current assets	361	2,237	[1]
Total assets	66,436	99,965	[1]
Current liabilities:
Accounts payable	1,490	3,654	[1]
Accrued compensation	3,340	3,495	[1]
Other accrued liabilities	2,140	6,948	[1]
Deferred revenues	2,248	2,186	[1]
Total current liabilities	9,218	16,283	[1]
Deferred revenues, net of current portion	1,161	1,299	[1]
Other long-term liabilities	5,183	3,943	[1]
Commitments and contingencies (note 8)			[1]
Stockholders’ equity:
Common stock	4	4	[1]
Additional paid-in capital	297,776	294,128	[1]
Accumulated other comprehensive income (loss)	139	(136)	[1]
Accumulated deficit	(247,045)	(215,556)	[1]
Total stockholders’ equity	50,874	78,440	[1]
Total liabilities and stockholders’ equity	$ 66,436	$ 99,965	[1]

[1] The Condensed Consolidated Balance Sheet as of December 31, 2012 has been derived from the audited consolidated financial statements as of that date, but does not include all disclosures including notes required by GAAP for complete financial statements.