CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities:
Net income	$ 43,867	$ 59,784
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	9,838	13,089
Bad debt expense	1,726	1,219
Deferred taxes	(6,214)	(4,439)
Release of liabilities for unrecognized tax benefits	0	(394)
Share-based compensation expense	10,557	8,424
Excess tax benefits from share-based compensation arrangements	0	(1,208)
Changes in operating assets and liabilities:
Accounts receivable	18,804	8,983
Prepaid expenses and other current assets	(3,954)	(657)
Deposits and other assets	(1,280)	(3,905)
Accounts payable and accrued expenses	(14,468)	(4,668)
Accrued compensation and employee benefits	(8,845)	717
Accrued restructuring costs	0	(56)
Deferred revenue and advance payments, net	1,156	19,435
Other long-term liabilities	(1,904)	(2,288)
Net cash provided by operating activities	49,283	94,036
Investing activities:
Proceeds from redemption of short-term investments	340,920	273,520
Purchases of property and equipment	(2,282)	(1,560)
Purchases of short-term investments	(411,666)	(292,948)
Net cash used in investing activities	(73,028)	(20,988)
Financing activities:
Proceeds from sale of class A common stock under exercise of employee stock options	1,677	1,157
Payment of taxes relating to net exercise of employee stock options	0	(3,739)
Excess tax benefits from share-based compensation arrangements	0	1,208
Payments on capital lease obligations and other financing arrangements	(17)	(166)
Net cash provided by (used in) financing activities	1,660	(1,540)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash	6,992	1,654
Net (decrease) increase in cash, cash equivalents, and restricted cash	(15,093)	73,162
Cash, cash equivalents and restricted cash, beginning of period	402,712	292,959
Cash, cash equivalents and restricted cash, end of period	$ 387,619	$ 366,121