Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 16,167	$ 7,475
Short-term investments	21,410	38,497
Accounts receivable, net of allowances for doubtful accounts and other adjustments of $1,121 (2012) and $1,382 (2011)	8,531	8,525
Income tax receivable	7,941	8,293
Inventories, net of reserves for excess and obsolete inventory of $436 (2012) and $417 (2011)	256	309
Prepaid expenses and other current assets	776	1,138
Deferred tax asset	8	8
Total current assets	55,089	64,245
Equipment and improvements, net	14,422	15,482
Other assets	219	214
Total assets	69,730	79,941
Current liabilities:
Accounts payable	1,986	3,181
Accrued liabilities	7,262	7,641
Deferred revenue	944	703
Total current liabilities	10,192	11,525
Non-current liabilities:
Long-term liabilities	3,408	3,546
Deferred tax liability	10	10
Total non-current liabilities	3,418	3,556
Commitments and contingencies
Stockholders' equity:
Preferred stock, par value $0.001 per share; 5,000,000 shares authorized; none issued or outstanding
Common stock, par value $0.001 per share; 50,000,000 shares authorized; 36,123,317 and 35,611,976 shares issued and outstanding at March 31, 2012 and December 31, 2011, respectively	36	36
Additional paid-in capital	208,835	207,927
Accumulated comprehensive deficit	(152,751)	(143,103)
Total stockholders' equity	56,120	64,860
Total liabilities and stockholders' equity	$ 69,730	$ 79,941