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 income	$ 2,341	$ 3,181
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	2,360	1,993
Amortization of intangible assets	559	614
Net (gains) losses from investments	51	(59)
Deferred income taxes	(1,519)	(549)
Stock-based compensation	1,860	1,323
Amortization of premium on investments	636	759
Foreign currency gains	(72)	(8)
Changes in assets and liabilities, net of acquisitions
Accounts receivable	25,186	29,518
Deferred commissions	(206)	1,743
Prepaid expenses and other current assets	1,271	(5,317)
Accounts payable	111	(544)
Accrued expenses and other liabilities	166	(669)
Deferred revenue	2,709	2,901
Net cash provided by operating activities	35,453	34,886
Cash flows from investing activities:
Purchases of property and equipment	(939)	(2,418)
Purchases of marketable investments	(4,125)	(40,301)
Proceeds from sales and maturities of marketable investments	17,750	34,090
Change in restricted cash		946
Other investing activity	75	33
Net cash provided by (used in) investing activities	12,761	(7,650)
Cash flows from financing activities:
Dividends paid on common stock	(3,350)	(3,195)
Repurchases of common stock		(7,700)
Proceeds from issuance of common stock under employee equity incentive plans	1,447	1,997
Excess tax benefits from stock-based compensation	109	183
Payment of deferred acquisition consideration		(139)
Net cash used in financing activities	(1,794)	(8,854)
Effect of exchange rate changes on cash and cash equivalents	(1,286)	978
Net increase in cash and cash equivalents	45,134	19,360
Cash and cash equivalents, beginning of period	98,810	81,047
Cash and cash equivalents, end of period	$ 143,944	$ 100,407