Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss			$ (226,807)	$ (247,550)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization			4,220	3,591
Loss on disposal of property and equipment			15	0
Equity-based compensation			63,655	41,559
(Accretion)/amortization of investment discounts and premiums			(11,667)	4,428
Loss from equity method investment	$ 4,000	$ 3,252	7,048	5,997
Deferral of equity method investment intra-entity profit on sales			5,656	5,656
Change in fair value of contingent consideration	0	(172)	100	249
In-process research and development charge			0	55,990
Changes in operating assets and liabilities:
Accounts receivable			(1,289)	(824)
Prepaid expenses and other current assets			(6,078)	434
Operating lease right-of-use assets			9,373	5,368
Other assets			(503)	(802)
Accounts payable			6,287	(3,710)
Accrued expenses			(12,525)	(721)
Deferred revenue			(28,919)	(30,099)
Operating lease liabilities			(8,217)	(4,458)
Net cash used in operating activities			(199,651)	(164,892)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment			(8,133)	(5,409)
Purchases of marketable securities			(625,319)	(31,524)
Maturities of marketable securities			476,666	224,583
Acquired in-process research and development, net of cash acquired of $287			0	(44,832)
Net cash (used in) provided by investing activities			(156,786)	142,818
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from options exercised			1,220	13,262
Issuance of shares through employee stock purchase plan			2,051	1,068
Net cash provided by financing activities			4,737	53,215
Net (decrease) increase in cash and cash equivalents and restricted cash equivalents			(351,700)	31,141
Cash, cash equivalents and restricted cash equivalents, beginning of period			535,463	125,486	$ 125,486
Cash, cash equivalents and restricted cash equivalents, end of period	183,763	156,627	183,763	156,627	535,463
Reconciliation of cash, cash equivalents and restricted cash equivalents to condensed consolidated balance sheet:
Cash and cash equivalents	171,806	147,781	171,806	147,781	523,506
Restricted cash equivalents, included in investments and other assets	11,957	8,846	11,957	8,846
Total cash, cash equivalents and restricted cash equivalents	183,763	156,627	183,763	156,627	$ 535,463
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Purchases of property and equipment unpaid at period end			2,998	3,750
Shares issued for Rewrite research milestone liability	24,126	0	24,126	0
Contingent consideration liability assumed in asset acquisition	$ 0	$ 10,541	0	10,541
At The Market Offerings [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock			$ 1,466	$ 38,885