Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ 2,087,103	$ 91,635	$ (84,031)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Stock-based compensation expense	325,047	293,236	240,623
Depreciation expense	72,420	61,397	61,398
Write-downs of inventories to net realizable value	20,413	15,292	0
Deferred income taxes (including benefit from valuation allowance release)	(1,512,325)	(120,513)	16,961
Unrealized gain on equity securities	(2,558)	0	0
Intangible asset impairment charges	29,000	255,340	0
Acquired in-process research and development	0	160,000	0
Deconsolidation of VIE	1,077	76,644	0
Other non-cash items, net	12,089	(853)	6,140
Changes in operating assets and liabilities:
Accounts receivable, net	(108,152)	(71,759)	(39,095)
Inventories	(31,965)	(47,484)	(19,368)
Prepaid expenses and other assets	16,684	(111,063)	(2,631)
Accounts payable	36,554	8,753	(11,745)
Accrued expenses and other liabilities	195,623	75,332	(5,565)
Early access sales accrual	129,276	158,985	73,416
Net cash provided by operating activities	1,270,286	844,942	236,103
Cash flows from investing activities:
Maturities of available-for-sale debt securities	431,576	369,214	757,562
Purchases of available-for-sale debt securities	(431,918)	(532,581)	(616,625)
Expenditures for property and equipment	(95,524)	(99,421)	(56,563)
Purchase of in-process research and development	0	(160,000)	0
Investment in note receivable	(15,000)	0	(20,000)
Investment in equity securities	(83,471)	0	(13,075)
Decrease in restricted cash due to deconsolidation of VIE	(7,896)	(61,602)	0
Other investing activities	75	1,061	(61)
Net cash used in (provided by) investing activities	(202,158)	(483,329)	51,238
Cash flows from financing activities:
Issuances of common stock under benefit plans	289,293	344,840	68,230
Repurchase of common stock	(350,043)	0	0
Payments on revolving credit facility	0	(300,000)	0
Advance from collaborator	7,500	12,500	75,000
Payments related to construction financing lease obligation	(5,462)	(541)	(432)
Proceeds related to construction financing lease obligation	9,566	27,182	0
Proceeds from capital lease financing	11,274	7,484	11,208
Payments on capital lease obligations	(27,926)	(18,795)	(17,597)
Repayments of advanced funding	(5,027)	(4,266)	0
Payments on senior secured term loan	0	0	(75,000)
Proceeds from revolving credit facility	0	0	74,965
Payments of debt issuance costs	0	0	(3,103)
Other financing activities	(394)	0	0
Net cash (used in) provided by financing activities	(71,219)	68,404	133,271
Effect of changes in exchange rates on cash	(6,182)	5,802	(4,666)
Net increase in cash, cash equivalents and restricted cash	990,727	435,819	415,946
Cash, cash equivalents and restricted cash—beginning of period	1,667,526	1,231,707	815,761
Cash, cash equivalents and restricted cash—end of period	2,658,253	1,667,526	1,231,707
Supplemental disclosure of cash flow information:
Cash paid for interest	66,458	68,696	83,656
Cash paid for (received from) income taxes	12,402	6,414	(2,579)
Non-cash investing and financing activities:
Capitalization of costs related to construction financing lease obligation	3,389	40,855	14,238
Issuances of common stock from employee benefit plans receivable	86	844	68
Proceeds from revolving credit facility directly paid to settle all outstanding obligations under the term loan	$ 0	$ 0	$ 225,000