Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Operating activities:
Net loss	$ (66,739)	$ (65,567)	$ (30,751)	$ (2,467)	$ (203,109)	$ (57,240)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock based compensation expense					3,815	1,634
Non-cash interest expense related to debt financing					374	706
Issuance of common stock for payment of compensation						78
Issuance of common stock in exchange for services						212
Changes in operating assets and liabilities:
Prepaid expenses and other assets					(872)	(309)
Accounts payable					30,596	3,697
Accrued expenses					15,427	5,065
Deferred revenue					1,983
Net cash used in operating activities					(151,786)	(46,157)
Investing activities:
Purchase of intangible assets						(20)
Net cash used in investing activities						(20)
Financing activities:
Net proceeds from issuance of common stock					134,140	139,760
Proceeds from exercise of stock options					1,965	572
Net proceeds from issuance of long-term debt					24,444	10
Net proceeds from issuance of convertible notes						467
Net proceeds from issuance of PPP loan						83
Net proceeds from issuance of bridge notes						350
Payments on PPP loan						(83)
Payments on bridge notes						(2,400)
Payments on convertible notes						(518)
Payments on notes payable to vendors						(776)
Net cash provided by financing activities					160,549	137,465
Net increase in cash and cash equivalents					8,763	91,288
Cash and cash equivalents, beginning of period		$ 67,737		143	67,737	143	$ 143
Cash and cash equivalents, end of period	$ 76,500		91,431		76,500	91,431	$ 67,737
Supplemental cash flow disclosure:
Cash paid for interest					961	671
Supplemental disclosure of non-cash investing and financing activities:
Issuance of stock options in lieu of cash compensation						180
Issuance of warrants for services			$ 1,948	$ 1		2,066
Conversion of notes payable and related accrued interest and fees to common stock						$ 4,316