Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 8,620	$ 11,763
Short-term investments	2,625	3,078
Accounts receivable, net of allowances for doubtful accounts and other adjustments of $608 (2014) and $617 (2013)	7,042	7,563
Income tax receivable	699	699
Inventories, net of reserves for excess and obsolete inventory of $274 (2014) and $301 (2013)	167	167
Prepaid expenses and other current assets	734	871
Deferred tax asset	152	152
Total current assets	20,039	24,293
Equipment and improvements, net	6,161	7,023
Other assets	223	222
Total assets	26,423	31,538
Current liabilities:
Accounts payable	1,623	1,632
Accrued liabilities	7,160	7,734
Deferred revenue	201	464
Total current liabilities	8,984	9,830
Non-current liabilities:
Deferred rent and other long-term liabilities	3,573	3,383
Deferred tax liability	154	154
Total non-current liabilities	3,727	3,537
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; 100,000,000 shares authorized; 38,566,187 and 36,994,318 shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively	39	37
Additional paid-in capital	215,325	214,619
Accumulated comprehensive deficit	(201,652)	(196,485)
Total stockholders' equity	13,712	18,171
Total liabilities and stockholders' equity	$ 26,423	$ 31,538