Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 10,005	$ 13,047
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	6,056	4,775
Amortization of intangible assets	770	582
Net losses from investments	62	997
Deferred income taxes	(1,305)	(921)
Stock-based compensation	6,191	6,423
Amortization of premium (discount) on investments	(17)	171
Foreign currency losses	462	444
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	31,857	20,140
Deferred commissions	3,716	2,906
Prepaid expenses and other current assets	(68)	(979)
Accounts payable	19	(1,208)
Accrued expenses and other liabilities	(12,111)	(6,041)
Deferred revenue	(8,205)	(3,473)
Net cash provided by operating activities	37,432	36,863
Cash flows from investing activities:
Acquisitions, net of cash acquired	(9,250)
Purchases of property and equipment	(3,161)	(5,806)
Purchases of marketable investments	(31,831)	(27,430)
Proceeds from sales and maturities of marketable investments	33,802	34,458
Other investing activity		200
Net cash provided by (used in) investing activities	(10,440)	1,422
Cash flows from financing activities:
Dividends paid on common stock	(10,839)	(10,205)
Repurchases of common stock	(9,946)	(39,967)
Proceeds from issuance of common stock under employee equity incentive plans	11,217	13,866
Taxes paid related to net share settlements of stock-based compensation awards	(2,509)	(2,511)
Net cash used in financing activities	(12,077)	(38,817)
Effect of exchange rate changes on cash and cash equivalents	(2,648)	3,534
Net increase in cash and cash equivalents	12,267	3,002
Cash and cash equivalents, beginning of period	79,790	76,958
Cash and cash equivalents, end of period	92,057	79,960
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 3,263	$ 7,662