Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Operating activities
Net income	$ 2,577	$ 2,062
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,765	3,707
Stock-based compensation	7,405	5,898
Share of loss of equity method investee	98	72
Changes in assets and liabilities:
Accounts receivable	(622)	(5,063)
Prepaid expenses and other assets	(901)	46
Accounts payable	(3,536)	(2,073)
Accrued compensation	307	892
Accrued expenses and other liabilities	958	(1,254)
Deferred revenues	(670)	(643)
Net cash provided by operating activities	8,381	3,644
Investing activities
Purchases of property and equipment	(3,493)	(2,841)
Purchases of marketable securities	(38,388)	(67,565)
Maturities of marketable securities	49,160	56,072
Purchase of other investments	(400)	(2,300)
Net cash provided by (used in) investing activities	6,879	(16,634)
Financing activities
Net proceeds from issuance of common stock under stock plans	8,885	5,557
Net cash provided by financing activities	8,885	5,557
Net increase (decrease) in cash and cash equivalents	24,145	(7,433)
Cash and cash equivalents at the beginning of the period	32,869	31,183
Cash and cash equivalents at the end of the period	57,014	23,750
Supplemental disclosure of cash flow information
Cash paid for income taxes	$ 56	$ 73