CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net loss		$ (34,081)	$ (53,819)
Adjustments to reconcile net loss to net cash from operating activities:
Stock-based compensation expense		7,304	8,055
Change in fair value of derivative liability - warrants	$ (2,722)	(2,722)
Impairment of prepaid manufacturing services	4,508	4,508
Non-cash interest expense		308	392
Depreciation and amortization expense		3,181	4,205
Non-cash manufacturing expense		462
Changes in operating assets and liabilities:
Prepaid expenses and other current assets		2,949	(651)
Prepaid manufacturing services		12
Operating right-of-use assets		1,003	745
Accounts payable		175	206
Accrued expenses		(1,725)	1,118
Deferred revenue		(24,970)	(11,953)
Operating lease liabilities		(1,962)	(920)
Net cash used in operating activities		(45,558)	(52,622)
Cash flows from investing activities:
Purchases of property and equipment		(362)	(2,913)
Net cash used in investing activities		(362)	(2,913)
Cash flows from financing activities:
Proceeds from exercise of common stock options			3,523
Net cash received from Employee Stock Purchase Program (ESPP)		126
Proceeds from issuance of common stock, net of issuance costs		20,618	61,681
Net cash provided by financing activities		20,744	65,204
Net (decrease) increase in cash, cash equivalents and restricted cash		(25,176)	9,669
Cash, cash equivalents and restricted cash, beginning of period		81,108	93,085
Cash, cash equivalents and restricted cash, end of period	55,932	55,932	102,754
Supplemental disclosures:
Cash paid for interest		1,696	1,713
Non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable and accrued expenses		28	388
Offering costs included in accrued expenses		267
Issuance of derivative liability - warrants		8,150
Reconciliation to amounts within the consolidated balance sheets
Cash and cash equivalents	51,762	51,762	98,584
Restricted cash	4,170	4,170	4,170
Cash, cash equivalents and restricted cash at end of period	$ 55,932	$ 55,932	$ 102,754