CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net income	$ 59,784	$ 66,820
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	13,089	16,172
Bad debt expense	1,219	683
Unrealized net loss on foreign currency forward contracts	0	1,641
Non-cash restructuring costs and adjustments	0	(127)
Deferred taxes	(4,439)	11,015
Release of liabilities for unrecognized tax benefits	(394)	(61)
Share-based compensation expense	8,424	12,503
Excess tax benefits from share-based compensation arrangements	(1,208)	(963)
Reclassification of foreign currency translation adjustment from other comprehensive income	0	(280)
Changes in operating assets and liabilities:
Accounts receivable	8,983	19,511
Prepaid expenses and other current assets	(657)	3,377
Deposits and other assets	(3,905)	1,562
Accounts payable and accrued expenses	(4,668)	(4,933)
Accrued compensation and employee benefits	717	(10,275)
Accrued restructuring costs	(56)	(1,940)
Deferred revenue and advance payments	19,435	11,153
Other long-term liabilities	(2,288)	(2,415)
Net cash provided by operating activities	94,036	123,443
Investing activities:
Proceeds from redemption of short-term investments	273,520	316,000
Purchases of property and equipment	(1,560)	(3,352)
Purchases of short-term investments	(292,948)	(344,033)
Capitalized software development costs	0	(9,598)
Decrease in restricted cash	92	113
Net cash used in investing activities	(20,896)	(40,870)
Financing activities:
Proceeds from sale of class A common stock under exercise of employee stock options	1,157	5,439
Payment of taxes relating to net exercise of employee stock options	(3,739)	0
Excess tax benefits from share-based compensation arrangements	1,208	963
Payments on capital lease obligations and other financing arrangements	(166)	(1,430)
Net cash (used in) provided by financing activities	(1,540)	4,972
Effect of foreign exchange rate changes on cash and cash equivalents	1,614	(4,276)
Net increase in cash and cash equivalents	73,214	83,269
Cash and cash equivalents, beginning of period	292,341	146,919
Cash and cash equivalents, end of period	365,555	230,188
Supplemental disclosure of noncash investing and financing activities:
Assets acquired under capital lease obligations and other financing arrangements	$ 0	$ 14