Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating activities
Net (loss) income	$ (231,801)	$ 1,604,715	$ (327,370)
Less: Net income from discontinued operations	0	1,961,225	1,935
Net loss from continuing operations	(231,801)	(356,510)	(329,305)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	8,564	9,240	9,790
Stock-based compensation expense	49,296	53,508	61,602
Net (accretion of discount) amortization of premium on marketable securities	(1,198)	6,949	3,022
Gain on sale of contingent payments	(127,853)	0	0
(Gain) loss on disposal of property and equipment	(48)	12	0
Non-cash operating lease expense	9,995	9,537	8,982
Changes in operating assets and liabilities:
Accounts receivable, net	(2,206)	0	0
Inventory	(8,492)	0	0
Other receivables	447	(4,378)	0
Prepaid expenses and other current and non-current assets	(176)	(26,846)	(3)
Accounts payable	3,436	1,863	3,330
Accrued expenses	(1,617)	66	6,765
Operating lease liabilities	(10,828)	(7,527)	(8,127)
Other liabilities	3,003	0	0
Net cash used in operating activities	(309,478)	(314,086)	(243,944)
Net cash used in operating activities - discontinued operations	0	(93,234)	(46,815)
Net cash used in operating activities	(309,478)	(407,320)	(290,759)
Investing activities
Purchases of marketable securities	(1,030,781)	(1,378,221)	(557,030)
Proceeds from maturities and sales of marketable securities	1,146,175	829,804	647,685
Proceeds from sale of contingent payments	131,784	0	0
Purchases of property and equipment	(4,881)	(5,741)	(14,106)
Proceeds from sale of equipment	964	0	0
Net cash provided by (used in) investing activities	243,261	(554,158)	76,549
Net cash provided by (used in) investing activities - discontinued operations	0	1,802,936	(803)
Net cash provided by investing activities	243,261	1,248,778	75,746
Financing activities
Payments on financing lease obligations	(331)	(578)	(336)
Purchase of treasury stock	0	(802,486)	0
Net proceeds from stock option exercises and employee stock purchase plan	2,681	37,296	11,317
Net cash provided by (used in) financing activities	2,350	(765,768)	10,981
Net cash provided by financing activities - discontinued operations	0	0	250,537
Net cash provided by (used in) financing activities	2,350	(765,768)	261,518
Net change in cash and cash equivalents	(63,867)	75,690	46,505
Cash and cash equivalents at beginning of the period	203,126	127,436	80,931
Cash and cash equivalents at end of the period	139,259	203,126	127,436
Supplemental disclosure of non-cash investing and financing transactions:
Additions to property and equipment in accounts payable and accrued expenses	158	1,678	465
Cash taxes paid	0	16,078	0
Financing lease liabilities arising from obtaining financing lease assets	$ 0	$ 511	$ 0