CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 90,694	$ 67,527
Adjustments to reconcile net profit to net cash provided by operating activities:
Deferred taxes	(8,608)	(5,910)
Depreciation and amortization	9,885	8,638
Stock-based compensation	26,223	24,474
Tax (shortfalls) benefits from stock-based awards	9,811	6,207
Excess tax benefit from share-based payment arrangements	(10,697)	(6,207)
Other non-cash operating activities	7,041	6,162
Changes in assets and liabilities, net of acquired assets and liabilities:
Accounts receivable	(38,433)	(22,904)
Inventories	(3,524)	(510)
Prepaid expenses and other assets	(5,025)	(4,786)
Accounts payable	(4,753)	4,902
Accrued and other long-term liabilities	4,446	8,259
Deferred revenues	29,787	12,733
Net cash provided by operating activities	106,847	98,585
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property, plant and equipment	(39,025)	(26,172)
Purchase of marketable securities	(241,364)	(195,399)
Proceeds from maturities of marketable securities	210,693	148,685
Proceeds from sales of marketable securities	24,224	12,518
Other investing activities	(6,031)	46
Net cash used in investing activities	(51,503)	(60,322)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	7,002	6,036
Common stock repurchases	(35,000)	(50,781)
Equity forward contract related to accelerated share repurchase	(15,000)	(21,000)
Excess tax benefit from share-based payment arrangements	10,697	6,207
Employees’ taxes paid upon the vesting of restricted stock units	(23,207)	(15,389)
Net cash used in financing activities	(55,508)	(74,927)
Effect of foreign exchange rate changes on cash and cash equivalents	156	(1,454)
Net decrease in cash and cash equivalents	(8)	(38,118)
Cash and cash equivalents, beginning of the period	167,714	$ 199,871
Cash and cash equivalents, end of the period	$ 167,706