Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ (1,733)	$ 3,030
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	1,996	1,679
Amortization of intangible assets	186	191
Net losses from investments	25	203
Deferred income taxes	93	(257)
Stock-based compensation	1,963	2,049
Amortization of premium on investments	25	61
Foreign currency losses	387	215
Changes in assets and liabilities
Accounts receivable	7,921	3,839
Deferred commissions	(122)	(235)
Prepaid expenses and other current assets	(5,454)	138
Accounts payable	133	(1,485)
Accrued expenses and other liabilities	(14,890)	(11,512)
Deferred revenue	17,275	21,538
Net cash provided by operating activities	7,805	19,454
Cash flows from investing activities:
Purchases of property and equipment	(1,324)	(1,540)
Purchases of marketable investments	(11,604)	(11,503)
Proceeds from sales and maturities of marketable investments	11,500	12,200
Other investing activity		184
Net cash used in investing activities	(1,428)	(659)
Cash flows from financing activities:
Dividends paid on common stock	(3,611)	(3,462)
Repurchases of common stock	(4,367)	(21,453)
Proceeds from issuance of common stock under employee equity incentive plans	2,530	2,723
Taxes paid related to net share settlements of stock-based compensation awards	(66)	(56)
Net cash used in financing activities	(5,514)	(22,248)
Effect of exchange rate changes on cash and cash equivalents	1,420	671
Net increase (decrease) in cash and cash equivalents	2,283	(2,782)
Cash and cash equivalents, beginning of period	79,790	76,958
Cash and cash equivalents, end of period	82,073	74,176
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 669	$ 115