Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 30,195	$ 21,641
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	16,403	15,114
Stock-based compensation expense	10,259	7,809
Unrealized gain on short term investments	(2,984)	(760)
Unrealized foreign exchange gain	(42)	(1,386)
Deferred income taxes	3,607	3,272
Change in fair value of earn-out consideration	(4,060)	0
Others, net	(67)	(209)
Change in operating assets and liabilities (net of effect of acquisitions):
Restricted cash	314	(1,197)
Accounts receivable	(19,621)	(10,013)
Prepaid expenses and other current assets	(1,177)	(1,143)
Accounts payable	(1,427)	(464)
Deferred revenue	4,996	2,516
Accrued employee costs	(10,282)	(8,175)
Accrued expenses and other liabilities	4,413	(3,058)
Advance income tax, net	(3,179)	3,625
Other assets	(433)	(405)
Net cash provided by operating activities	26,915	27,167
Cash flows from investing activities:
Purchase of fixed assets	(14,872)	(14,380)
Business acquisition (net of cash acquired)	0	(44,270)
Purchase of short-term investments	(132,275)	(71,863)
Proceeds from redemption of short-term investments	41,179	6,001
Net cash used for investing activities	(105,968)	(124,512)
Cash flows from financing activities:
Principal payments on capital lease obligations	(240)	(358)
Proceeds from borrowings	0	30,000
Repayments of borrowings	(25,000)	(10,000)
Payment of debt issuance costs	0	(74)
Acquisition of treasury stock	(9,704)	(5,105)
Proceeds from exercise of stock options	4,195	2,366
Net cash (used for)/provided by financing activities	(30,749)	16,829
Effect of exchange rate changes on cash and cash equivalents	(2,408)	(1,332)
Net decrease in cash and cash equivalents	(112,210)	(81,848)
Cash and cash equivalents, beginning of period	205,323	176,499
Cash and cash equivalents, end of period	$ 93,113	$ 94,651