Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net income	$ 72,024	$ 59,952
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	27,739	24,734
Stock-based compensation expense	24,564	17,902
Amortization of operating lease right-of-use assets	12,005	13,632
Unrealized Gain (Loss) on Investments	(275)	6,777
Unrealized foreign currency exchange gain, net	(10,280)	(2,634)
Deferred income tax benefit	(1,462)	(14,737)
Allowance / (reversal) of expected credit losses	170	(390)
Fair value changes in contingent consideration	1,000	0
Gain/(loss) from equity-method investment	(257)	28
Amortization of non-cash interest expense related to convertible senior notes	0	1,364
Others, net	783	144
Change in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	(46,385)	(34,152)
Prepaid expenses and other current assets	2,861	189
Advance income tax, net	8,684	39
Other assets	(6,584)	1,589
Accounts payable	(1,107)	(2,458)
Deferred revenue	4,276	(20,832)
Accrued employee costs	(34,016)	3,833
Accrued expenses and other liabilities	11,190	12,290
Operating lease liabilities	(11,922)	(13,327)
Net cash provided by operating activities	53,008	53,943
Cash flows from investing activities:
Purchases of property and equipment	(25,054)	(19,903)
Proceeds from sale of property and equipment	154	527
Business acquisition (net of cash and cash equivalents acquired)	(2,572)	0
Purchases of investments	(96,082)	(32,987)
Proceeds from redemption of investments	82,567	64,031
Net cash (used for)/provided by investing activities	(40,987)	11,668
Cash flows from financing activities:
Principal payments of finance lease liabilities	(75)	(107)
Proceeds from borrowings	35,000	25,000
Repayments of borrowings	(10,000)	(99,000)
Acquisition of treasury stock	(60,191)	(57,424)
Proceeds from exercise of stock options	0	174
Net cash used for financing activities	(35,266)	(131,357)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(5,365)	(2,237)
Net decrease in cash, cash equivalents and restricted cash	(28,610)	(67,983)
Cash, cash equivalents and restricted cash at the beginning of the period	143,810	225,519
Cash, cash equivalents and restricted cash at the end of the period	115,200	157,536
Cash paid during the period for:
Interest	2,694	3,599
Income taxes, net of refunds	14,301	18,710
Supplemental disclosure of non-cash investing and financing activities:
Assets acquired under finance lease	$ 118	$ 50