Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income	$ 651,639	$ 340,074	$ 174,560
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	32,921	32,245	31,259
Share-based compensation expense	280,254	190,054	320,786
Gain on sale of intangible asset	(350,000)
Amortization of debt discount and debt issue costs	5,941	12,456	12,601
Amortization of discount or premium on investments	2,132	5,231	4,501
Other	(515)	6,493	3,182
Excess tax benefits from share-based compensation	(37,426)	(30,845)	(9,299)
Changes in operating assets and liabilities:
Accounts receivable	(30,540)	(35,689)	(10,027)
Inventories	(6,794)	(21,032)	(12,394)
Accounts payable and accrued expenses	16,972	(6,753)	7,507
Other assets and liabilities	(181,823)	(136,975)	(97,409)
Net cash provided by operating activities	382,761	355,259	425,267
Cash flows from investing activities:
Purchases of property, plant and equipment, net	(49,792)	(47,439)	(31,910)
Purchases of held-to-maturity investments	(62,781)	(118,672)	(762,198)
Maturities of held-to-maturity investments	320,369	549,576	529,900
Gain on sale of intangible asset	350,000
Purchase of investments under the cost method, net	(54,217)	(45,000)	(30,766)
Net cash provided by (used in) investing activities	503,579	338,465	(294,974)
Cash flows from financing activities:
Principal payments of debt	(133,150)	(177,800)	(1,320)
Payments to repurchase common stock	(394,484)	(483,077)	(42,439)
Proceeds from line of credit		140,000
Payments on the line of credit		(140,000)
Proceeds from exercise of stock options	39,311	50,168	26,611
Issuance of stock under employee stock purchase plan	3,954	3,329	2,734
Excess tax benefits from share-based compensation	37,426	30,845	9,299
Net cash used in financing activities	(446,943)	(576,535)	(5,115)
Effect of exchange rate changes on cash and cash equivalents	(5,296)	(3,750)	(319)
Net increase in cash and cash equivalents	434,101	113,439	124,859
Cash and cash equivalents, beginning of year	397,697	284,258	159,399
Cash and cash equivalents, end of year	831,798	397,697	284,258
Supplemental cash flow information:
Cash paid for interest	1,015	5,453	5,518
Cash paid for income taxes	293,331	195,564	142,140
Non-cash investing and financing activities:
Acquisitions-non-cash consideration		5,200
Non-cash additions to property, plant and equipment	1,078	3,150	$ 9,018
Issuance of common stock upon conversion of convertible notes	$ 321,801	$ 189,311