CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 201,971	$ 138,599
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred taxes	3,667	6,145
Depreciation and amortization	24,066	16,743
Stock-based compensation	32,720	29,057
Equity in losses of investee	5,478	3,336
Other non-cash operating activities	4,543	5,837
Changes in assets and liabilities, net of effects of acquisitions:
Accounts receivable	(44,266)	(52,038)
Inventories	(15,586)	(8,616)
Prepaid expenses and other assets	(9,366)	388
Accounts payable	10,743	4,410
Accrued and other long-term liabilities	(53,442)	(14,802)
Long-term income tax payable	1,610	(551)
Deferred revenues	54,983	29,580
Net cash provided by operating activities	217,121	158,088
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions, net of cash acquired	0	(8,953)
Purchase of property, plant and equipment	(115,295)	(78,045)
Purchase of marketable securities	(78,405)	(212,226)
Proceeds from maturities of marketable securities	207,475	173,094
Proceeds from sales of marketable securities	9,560	32,352
Loan advances to equity investee	0	(15,000)
Loan repayment from equity investee	30,000	0
Other investing activities	668	(2,940)
Net cash provided by (used in) investing activities	54,003	(111,718)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	8,585	7,521
Common stock repurchases	(100,000)	(38,793)
Equity forward contract related to accelerated share repurchase	0	15,000
Employees’ taxes paid upon the vesting of restricted stock units	(79,330)	(37,968)
Net cash used in financing activities	(170,745)	(84,240)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash	(1,923)	3,640
Net increase (decrease) in cash, cash equivalents, and restricted cash	98,456	(34,230)
Cash, cash equivalents, and restricted cash at beginning of the period	450,125	393,019
Cash, cash equivalents, and restricted cash at end of the period	548,581	358,789
SUPPLEMENTAL CASH FLOW INFORMATION:
Accounts payable or accrued liabilities related to property, plant and equipment	20,854	20,291
Conversion of convertible notes receivable into equity securities	$ 4,862	$ 0