CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 36,177	$ 32,444
Adjustments to reconcile net profit to net cash provided by operating activities:
Deferred taxes	291	12,769
Depreciation and amortization	4,308	4,776
Stock-based compensation	11,648	9,132
Excess tax benefit from share-based payment arrangements	(4,779)	(13,568)
Other non-cash operating activities	2,614	1,977
Changes in assets and liabilities, net of acquired assets and liabilities:
Accounts receivable	(12,233)	(13,939)
Inventories	1,334	(1,870)
Prepaid expenses and other assets	(10,527)	(1,790)
Accounts payable	1,871	265
Accrued and other long-term liabilities	(1,078)	(15,286)
Deferred revenues	6,019	3,083
Net cash provided by operating activities	35,645	17,993
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property, plant and equipment	(15,612)	(4,996)
Purchase of marketable securities	(113,508)	(157,919)
Proceeds from maturities of marketable securities	86,908	53,137
Proceeds from sales of marketable securities	5,505	10,564
Other investing activities	46	(133)
Net cash used in investing activities	(36,661)	(99,347)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	4,552	11,946
Common stock repurchases	(1,781)	0
Excess tax benefit from share-based payment arrangements	4,779	13,568
Employees’ taxes paid upon the vesting of restricted stock units	(14,647)	(4,453)
Net cash (used in) provided by financing activities	(7,097)	21,061
Effect of foreign exchange rate changes on cash and cash equivalents	(1,780)	106
Net decrease in cash and cash equivalents	(9,893)	(60,187)
Cash and cash equivalents, beginning of the period	199,871	242,953
Cash and cash equivalents, end of the period	$ 189,978	$ 182,766