CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2022		Dec. 31, 2021	Mar. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities:
Net loss	$ (52,430)	[1]	$ 224,613		$ (269,722)	$ (28,597)	$ (479,743)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation					14,328	15,487	13,365
Amortization of right-of-use operating lease assets					5,362	1,721	1,731
Amortization of other assets					2,415	2,352	2,064
Amortization of premium on investments, net					7,389	17,776	11,521
Amortization of debt issuance costs					5,373	4,958	3,255
Stock-based compensation expense					100,264	120,678	230,117
Loss on early retirement of debt					0	8,627	0
Non-cash losses related to disposal of property, plant and equipment					531	0	0
Gain on sale of real estate assets	(150,100)				(150,135)	0	0
Gain on investments					224	(1,092)	(16,540)
Deferred income taxes, including changes in valuation allowance					0	0	341,729
Non-cash losses related to other assets					2,030	2,707	1,948
Changes in operating assets and liabilities:
Contracts receivable					36,358	14,308	(13,170)
Inventories					2,773	(2,841)	(1,261)
Other current and long-term assets					(24,682)	(877)	(9,975)
Long-term income taxes receivable (payable)					0	1,008	(89)
Accounts payable					1,094	(6,000)	(2,755)
Income taxes					6,213	(1,288)	(31,190)
Accrued compensation					10,368	(26,918)	28,371
Accrued liabilities and other current liabilities					46,695	(8,381)	32,424
Deferred contract revenue					(71,248)	(82,829)	(75,910)
Net cash provided by (used in) operating activities					(274,370)	30,799	35,892
Investing activities:
Purchases of short-term investments					(1,485,772)	(1,124,193)	(1,570,410)
Proceeds from sale of short-term investments					989,152	1,344,185	1,885,935
Purchases of property, plant and equipment					(15,721)	(11,955)	(35,120)
Proceeds from sale of real estate assets					254,083	0	0
Acquisition of licenses and other assets, net					(4,378)	(5,946)	(5,928)
Purchases of strategic investments					0	(7,185)	0
Net cash provided by (used in) investing activities					(262,636)	194,906	274,477
Financing activities:
Proceeds from equity, net					6,373	11,565	52,036
Payments of tax withholdings related to vesting of employee stock awards and exercise of employee stock options					(10,953)	(16,725)	(13,411)
Proceeds from the issuance of 0 percent convertible senior notes					0	632,500	0
Royalty monetization issuance costs					(29)	0	0
0 percent convertible senior notes issuance costs					0	(15,609)	0
Repurchase of $247.9 million principal amount of 1 percent convertible senior notes					0	(256,963)	0
Repayment of remaining principal amount of 1 percent convertible senior notes at maturity					0	(61,967)	0
Proceeds from issuance of warrants					0	89,752	0
Purchase of note hedges					0	(136,620)	0
Repurchases and retirements of common stock				$ (90,500)	0	0	(90,548)	$ (34,400)
Principal payments on debt					(50,686)	0	0
Purchase of noncontrolling interest of Akcea Therapeutics, Inc., including cash payments for cancellation of Akcea Therapeutics, Inc. equity awards					0	0	(544,686)
Net cash provided by (used in) financing activities					(55,295)	245,933	(596,609)
Effects of exchange rates on cash					(418)	(111)	617
Net increase (decrease) in cash and cash equivalents					(592,719)	471,527	(285,623)
Cash and cash equivalents at beginning of year				$ 683,287	869,191	397,664	683,287
Cash and cash equivalents at end of year	$ 276,472		$ 869,191		276,472	869,191	397,664	$ 683,287
Supplemental disclosures of cash flow information:
Interest paid					2,898	4,778	6,247
Income taxes paid					5,010	38	25,855
Supplemental disclosures of non-cash investing and financing activities:
Right-of-use assets obtained in exchange for lease liabilities					168,931	6,641	2,149
Amounts accrued for capital and patent expenditures					$ 4,767	$ 705	$ 4,059

[1] Our net loss for the three months ended December 31, 2022 includes the $150.1 million gain we recognized from the sale and leaseback transaction for our headquarters in Carlsbad, California.