Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating activities
Net (loss) income	$ (6,389)	$ 293,156	$ 76,713
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	4,342	3,812	4,296
Amortization of right-of-use assets	2,934	2,856	2,762
Inventory write-off	0	34,288	2,588
Amortization of premiums (accretion of discounts) on marketable securities	(16,555)	(4,181)	470
Loss on debt extinguishment	0	0	5,232
Change in fair value of warrant liability	0	(1,801)	49,354
Stock-based compensation expense	42,592	32,915	21,285
Non-cash interest expense	1,120	1,088	1,608
Gain on sale of assets	(1,000)	(1,000)	(1,000)
Bad debt expense (Note 9)	12,313	0	0
Changes in operating assets and liabilities:
Accounts and other receivables, net	43,268	(15,699)	(109,155)
Inventories, net	3,909	(32,399)	(234)
Prepaid manufacturing	0	159,655	(130,232)
Prepaid expenses and other current assets	(4,673)	(11,865)	(64,558)
Other assets	570	87	175
Accounts payable	1,952	691	(767)
CEPI accrual (Note 9)	0	(21,110)	128,848
Lease liabilities	(3,629)	(3,125)	(3,234)
Deferred revenue	0	(349,864)	311,652
Accrued and other liabilities	19,809	(24,788)	39,725
Net cash provided by operating activities	100,563	62,716	335,528
Investing activities
Purchases of marketable securities	(636,921)	(632,306)	(164,928)
Proceeds from maturities and redemptions of marketable securities	486,097	322,450	187,630
Purchases of property and equipment, net	(4,104)	(7,139)	(9,477)
Proceeds from sale of assets, net of transaction costs	1,000	1,000	1,000
Net cash (used in) provided by investing activities	(153,928)	(315,995)	14,225
Financing activities
Proceeds from issuances of common stock, net	0	0	28,156
Proceeds from issuance of Convertible Notes, net	0	0	219,822
Purchases of capped call options	0	0	(27,240)
Repayment of long-term debt	0	0	(190,194)
Proceeds from warrants exercises	0	8,455	17,814
Proceeds from exercise of stock options and release of restricted stock awards, net	6,360	9,639	6,577
Proceeds from Employee Stock Purchase Plan	1,535	1,431	841
Payments for taxes related to net share settlement of RSUs	(6,509)	0	0
Net cash provided by financing activities	1,386	19,525	55,776
Effect of exchange rate changes on cash and cash equivalents, and restricted cash	324	(443)	(1,431)
Net increase (decrease) in cash and cash equivalents, and restricted cash	(51,655)	(234,197)	404,098
Cash and cash equivalents, and restricted cash at beginning of year	202,211	436,408	32,310
Cash and cash equivalents, and restricted cash at end of year	150,556	202,211	436,408
Supplemental disclosure of cash flow information
Cash paid during the year for income taxes	2,014	2,208	1,312
Cash paid during the year for interest	5,638	5,638	9,815
Reclassification of contract asset from other current assets to other assets	71,307	0	0
Reclassification of CEPI accrual to CEPI accrual long-term	(60,337)	0	0
Advance Payments forgiven per CEPI-Bio E Assignment Agreement (Note 9)	(47,401)	0	0
Non-cash investing and financing activities:
Purchases of property and equipment, not yet paid	299	1,015	591
Right-of-use assets obtained in exchange for operating lease liabilities	$ 1,332	$ 2,848	$ 2,468