CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net loss	$ (2,163)	$ (5,267)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	820	738
Depreciation and amortization	320	343
Other	34	14
Changes in assets and liabilities:
Accounts receivable	2,027	640
Inventories	23	(1,153)
Other current assets and prepaid expenses	60	444
Other long-term assets	35	28
Accounts payable	54	101
Accrued liabilities	(2,504)	(661)
Other long-term liabilities	259	27
Deferred revenue	584	(118)
Income tax liability	(92)	(9)
Net cash used in operating activities	(543)	(4,873)
Cash flows from investing activities:
Acquisition of property and equipment	(525)	(277)
Business acquisition	0	(5,091)
Proceeds from sales of marketable and long-term investments	500	10,729
Proceeds from maturities of marketable investments	11,050	11,135
Purchase of marketable investments	(20,473)	(13,442)
Net cash provided by (used in) investing activities	(9,448)	3,054
Cash flows from financing activities:
Proceeds from exercise of stock options and employee stock purchase plan	3,717	586
Net cash provided by financing activities	3,717	586
Net decrease in cash and cash equivalents	(6,274)	(1,233)
Cash and cash equivalents at beginning of period	23,546	14,020
Cash and cash equivalents at end of period	$ 17,272	$ 12,787