CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net loss	$ (4,469)	$ (7,625)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Stock-based compensation	2,370	2,334
Depreciation and amortization	973	1,186
Other	43	(113)
Changes in assets and liabilities:
Accounts receivable	1,347	(2,698)
Inventories	693	(196)
Other current assets and prepaid expenses	212	717
Other long-term assets	49	(31)
Accounts payable	(7)	(276)
Accrued liabilities	(1,877)	(163)
Other long-term liabilities	233	(24)
Deferred revenue	1,870	905
Income tax liability	(343)	(7)
Net cash provided by (used in) operating activities	1,094	(5,991)
Cash flows from investing activities:
Acquisition of property, equipment and software	(979)	(358)
Business acquisition	0	(5,091)
Proceeds from sales of marketable and long-term investments	12,108	26,361
Proceeds from maturities of marketable investments	26,315	34,445
Purchase of marketable investments	(43,901)	(39,864)
Net cash provided by (used in) investing activities	(6,457)	15,493
Cash flows from financing activities:
Repurchase of common stock	(7,623)	0
Proceeds from exercise of stock options and employee stock purchase plan	4,600	812
Net cash provided by (used in) financing activities	(3,023)	812
Net increase (decrease) in cash and cash equivalents	(8,386)	10,314
Cash and cash equivalents at beginning of period	23,546	14,020
Cash and cash equivalents at end of period	$ 15,160	$ 24,334