CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net loss	$ (2,801)	$ (6,733)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Stock-based compensation	1,622	1,525
Depreciation and amortization	646	768
Other	50	0
Changes in assets and liabilities:
Accounts receivable	1,299	(1,057)
Inventories	596	(441)
Other current assets and prepaid expenses	242	503
Other long-term assets	49	(53)
Accounts payable	323	(374)
Accrued liabilities	(1,952)	(241)
Other long-term liabilities	225	3
Deferred revenue	1,117	385
Income tax liability	(87)	(9)
Net cash provided by (used in) operating activities	1,329	(5,724)
Cash flows from investing activities:
Acquisition of property and equipment	(703)	(311)
Business acquisition	0	(5,091)
Proceeds from sales of marketable and long-term investments	4,975	17,795
Proceeds from maturities of marketable investments	16,200	19,835
Purchase of marketable investments	(37,243)	(23,536)
Net cash provided by (used in) investing activities	(16,771)	8,692
Cash flows from financing activities:
Proceeds from exercise of stock options and employee stock purchase plan	3,781	800
Net cash provided by financing activities	3,781	800
Net increase (decrease) in cash and cash equivalents	(11,661)	3,768
Cash and cash equivalents at beginning of period	23,546	14,020
Cash and cash equivalents at end of period	$ 11,885	$ 17,788