CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities:
Net income	$ 9,039	$ 11,269
Adjustments to reconcile net income to cash provided by operating activities:
Excess tax benefits from exercise or vesting of equity awards	(2,280)	(2,526)
Deferred income taxes	(1,525)	(899)
Depreciation and amortization	11,258	11,412
Stock-based compensation expense	14,914	8,453
Foreign currency transaction loss (gain)	3,930	(318)
Other non-cash items	550	495
Change in operating assets and liabilities:
Trade accounts receivable	16,645	51,155
Income taxes receivable and other current assets	(4,853)	(3,836)
Accounts payable and accrued expenses	(10,507)	94
Deferred revenue	2,378	(214)
Other long-term assets and liabilities	(150)	(1,150)
Cash provided by operating activities	39,399	73,935
Investing activities:
Purchases of marketable securities	(31,504)	(29,547)
Proceeds from maturities and called marketable securities	21,120	15,996
Payments for acquisitions	(535)	(1,593)
Investment in property and equipment	(7,293)	(2,864)
Cash used in investing activities	(18,212)	(18,008)
Financing activities:
Issuance of common stock for share-based compensation plans	587	338
Excess tax benefits from exercise or vesting of equity awards	2,280	2,526
Dividend payments to shareholders	(4,594)	(2,290)
Common stock repurchases for tax withholdings for net settlement of equity awards	(4,432)	(3,402)
Common stock repurchases under share repurchase programs	(7,075)	(8,459)
Cash used in financing activities	(13,234)	(11,287)
Effect of exchange rates on cash and cash equivalents	(1,674)	2,240
Net increase in cash and cash equivalents	6,279	46,880
Cash and cash equivalents, beginning of period	114,585	80,231
Cash and cash equivalents, end of period	$ 120,864	$ 127,111