Condensed Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 32,017	$ 51,250
Investments	11,786
Restricted Cash	1,094	1,343
Accounts receivable _ net of allowance of $ 38 and $30	4,363	3,190
Inventories	3,175	1,993
Other current assets	382	226
Total current assets	52,817	58,002
Property and equipment , net	7,347	7,074
Intangible assets, net	2,566	1,832
Other long-term assets	1,108	1,108
Total assets	63,838	68,016
Current liabilities
Accounts payable	2,315	2,445
Accrued compensation	1,791	3,076
Current portion of loan payable	353	638
Other current liabilities	3,515	3,015
Total current liabilities	7,974	9,174
Long-term liabilities
Loan payable, net of current portion	59	63
Other noncurrent liabilities	2,300	2,329
Total liabilities	10,333	11,566
Stockholders' equity
Common stock, $0.0001 par value; 100,000 authorized; 32,750 and 32,753 shares issued and outstanding as of March 31, 2013 and December 31, 2012, respectively	3	3
Preferred stock, $0.0001 par value; 5,000 authorized, none issued
Additional paid-in capital	248,683	247,449
Accumulated deficit	(194,741)	(190,566)
Accumulated other comprehensive loss	(440)	(436)
Total stockholders' equity	53,505	56,450
Total liabilities and stockholders' equity	$ 63,838	$ 68,016