Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 8,749	$ 5,526
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	4,041	4,203
Amortization of intangible assets	419	445
Net losses from investments	54	9
Deferred income taxes	(1,409)	(1,514)
Stock-based compensation	3,761	3,661
Amortization of premium on investments	187	381
Foreign currency losses	147	70
Changes in assets and liabilities
Accounts receivable	24,445	24,353
Deferred commissions	1,953	2,769
Prepaid expenses and other current assets	892	(511)
Accounts payable	189	(195)
Accrued expenses and other liabilities	(10,891)	(7,268)
Deferred revenue	(1,915)	(7,168)
Net cash provided by operating activities	30,622	24,761
Cash flows from investing activities:
Purchases of property and equipment	(2,318)	(1,678)
Purchases of marketable investments	(23,902)	(18,575)
Proceeds from sales and maturities of marketable investments	14,025	12,478
Other investing activity	(35)	266
Net cash used in investing activities	(12,230)	(7,509)
Cash flows from financing activities:
Dividends paid on common stock	(6,428)	(6,126)
Repurchases of common stock		(11,786)
Proceeds from issuance of common stock under employee equity incentive plans	4,147	1,906
Excess tax benefits from stock-based compensation	70	31
Net cash used in financing activities	(2,211)	(15,975)
Effect of exchange rate changes on cash and cash equivalents	(656)	(764)
Net increase in cash and cash equivalents	15,525	513
Cash and cash equivalents, beginning of period	53,331	49,650
Cash and cash equivalents, end of period	$ 68,856	$ 50,163