Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (18,591)	$ (8,066)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	151	180
Stock-based compensation	1,809	347
Change in fair value of warrant liability		(8)
Gain on asset disposal	(22)
Amortization of operating lease right-of-use assets	368
Net accretion and amortization in marketable securities	351
Amortization of debt issuance costs	29
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	607	70
Accounts payable	3,054	(294)
Accrued expenses and other liabilities	(1,552)	(227)
Operating lease liabilities	(368)
Net cash used in operating activities	(14,164)	(7,998)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(385)	(365)
Purchases of marketable securities	(65,506)	(24,082)
Proceeds from maturities of marketable securities	18,005
Net cash used in investing activities	(47,886)	(24,447)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments on Series C issuance costs	(192)	(2,491)
Proceeds from stock option exercises	84
Payments on capital lease obligations		(32)
Net cash used in financing activities	(108)	(2,523)
Net decrease in cash, cash equivalents and restricted cash	(62,158)	(34,968)
Cash, cash equivalents and restricted cash at beginning of period	116,174	59,836
Cash, cash equivalents and restricted cash at end of period	54,016	24,868
SUPPLEMENTAL NON-CASH OPERATING INFORMATION:
Right-of-use assets obtained in exchange for lease liabilities	14,477
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING INFORMATION:
Property and equipment additions included in accounts payable and accrued liabilities	1,396
Issuance costs for convertible preferred units included in accounts payable and accrued liabilities		141
Accrued tax distributions	14	1
Reconciliation of cash, cash equivalents and restricted cash as shown in the condensed consolidated statement of cash flows
Cash and cash equivalents	53,668	24,719
Restricted cash	348	149
Total cash, cash equivalents and restricted cash	$ 54,016	$ 24,868