Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 14,113	$ 16,378
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	3,335	2,740
Amortization of intangible assets	1,898	2,715
Net gains from investments	(648)	(1,829)
Deferred income taxes	5,820	(537)
Stock-based compensation	3,093	3,686
Amortization of premium on investments	2,523	1,728
Foreign currency losses	1,202	683
Other non-cash items		89
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	31,273	27,524
Deferred commissions	3,193	913
Prepaid expenses and other current assets	926	(3,295)
Accounts payable	(1,732)	1,927
Accrued expenses	(3,428)	(2,692)
Deferred revenue	(15,061)	(12,342)
Net cash provided by operating activities	46,507	37,688
Cash flows from investing activities:
Acquisitions	(7,164)	(1,660)
Purchases of property and equipment	(33,194)	(6,248)
Purchases of marketable investments	(81,008)	(105,102)
Proceeds from sales and maturities of marketable investments	58,888	118,235
Decrease in restricted cash	13,272	1,851
Other investing activity	307	314
Net cash provided by (used in) investing activities	(48,899)	7,390
Cash flows from financing activities:
Proceeds from issuance of common stock under employee equity incentive plans	7,017	10,773
Excess tax benefits from stock-based compensation	432	399
Repurchases of common stock	(18,405)	(13,951)
Net cash used in financing activities	(10,956)	(2,779)
Effect of exchange rate changes on cash and cash equivalents	7	(2,004)
Net increase (decrease) in cash and cash equivalents	(13,341)	40,295
Cash and cash equivalents, beginning of period	86,927	97,805
Cash and cash equivalents, end of period	$ 73,586	$ 138,100