CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities:
Net income (loss)	$ 657	$ (7,906)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	2,756	1,657
Reduction in carrying amount of right-of-use assets	2,053	2,007
Credit losses and sales allowances	828	827
Net realized loss on short-term investments	0	41
Deferred taxes	957	(1,694)
Share-based compensation expense	3,111	3,017
Changes in operating assets and liabilities:
Accounts receivable	14,406	10,266
Prepaid expenses and other current assets	(3,295)	(3,070)
Deposits and other assets	84	(134)
Accounts payable and accrued expenses	(154)	(3,108)
Accrued compensation and employee benefits	(13,031)	(12,195)
Deferred revenue and advance payments	22,001	38,502
Operating lease liabilities	(2,238)	(2,074)
Other long-term liabilities	934	320
Net cash provided by operating activities	29,069	26,456
Investing activities:
Proceeds from redemption of short-term investments	10,000	314,403
Purchases of property and equipment	(661)	(6,011)
Purchases of short-term investments	(9,928)	(138,099)
Net cash (used in) provided by investing activities	(589)	170,293
Financing activities:
Proceeds from sale of class A common stock under exercise of employee stock options	340	1,507
Purchases of treasury stock	(50,747)	(48,244)
Net cash used in financing activities	(50,407)	(46,737)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash	(3,871)	(1,133)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(25,798)	148,879
Cash, cash equivalents, and restricted cash, beginning of period	457,816	110,786
Cash, cash equivalents, and restricted cash, end of period	$ 432,018	$ 259,665