CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities:
Net income	$ 14,867	$ 14,272
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,818	4,553
Bad debt expense	1,044	531
Deferred taxes	(1,812)	688
Share-based compensation expense	3,115	1,504
Excess tax benefits from share-based compensation arrangements	0	(1,266)
Changes in operating assets and liabilities:
Accounts receivable	9,584	11,915
Prepaid expenses and other current assets	(58)	(3,551)
Deposits and other assets	75	4
Accounts payable and accrued expenses	(16,295)	(3,093)
Accrued compensation and employee benefits	(10,795)	(4,083)
Accrued restructuring costs	0	(26)
Deferred revenue and advance payments	23,811	30,065
Other long-term liabilities	(833)	(686)
Net cash provided by operating activities	26,521	50,827
Investing activities:
Proceeds from redemption of short-term investments	91,140	63,500
Purchases of property and equipment	(820)	(193)
Purchases of short-term investments	(163,421)	(97,417)
Net cash used in investing activities	(73,101)	(34,110)
Financing activities:
Proceeds from sale of class A common stock under exercise of employee stock options	1,095	241
Payment of taxes relating to net exercise of employee stock options	0	(3,739)
Excess tax benefits from share-based compensation arrangements	0	1,266
Payments on capital lease obligations and other financing arrangements	(6)	(122)
Net cash provided by (used in) financing activities	1,089	(2,354)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash	2,306	2,266
Net (decrease) increase in cash, cash equivalents, and restricted cash	(43,185)	16,629
Cash, cash equivalents and restricted cash, beginning of period	402,712	292,959
Cash, cash equivalents and restricted cash, end of period	$ 359,527	$ 309,588