STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (37,730)	$ (78,751)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	2,759	2,597
Property and equipment and right-of-use asset impairment	0	740
Amortization of financing costs	981	383
Stock-based compensation	3,528	10,774
Decrease (increase) in the carrying amount of right-of-use assets	2,417	(352)
Gain on lease modification	(133)	0
Loss on sale of equipment	7	0
(Increase) decrease in:
Receivables	1,107	3,555
Prepaid expenses and other current assets	867	9,189
Other noncurrent assets	131	201
Increase (decrease) in:
Accounts payable	(25)	274
Accrued expenses	(668)	(10,512)
Lease liabilities	(2,501)	434
Other non-current liabilities	28	0
Net cash used in operating activities	(29,232)	(61,468)
Cash flows from investing activities:
Purchases of property and equipment	(216)	(3,323)
Proceeds from the sale of property and equipment	23	0
Net cash used in investing activities	(193)	(3,323)
Cash flows from financing activities:
Proceeds from long-term debt borrowing	0	25,000
Debt issuance costs	0	(260)
Proceeds from exercise of stock options	21	1,036
Proceeds from the issuance of common stock	14,724	0
Repurchase of common stock	(45)	0
Repayment of long-term debt	(8,333)	0
Net cash provided by financing activities	6,367	25,776
Net decrease in cash, cash equivalents and restricted cash	(23,058)	(39,015)
Cash, cash equivalents and restricted cash, beginning of period	76,054	115,069
Cash, cash equivalents and restricted cash, end of period	52,996	76,054
Supplementary disclosure of cash flow information:
Cash paid for interest	2,171	630
Amounts included in accrued expenses and accounts payable related to property and equipment	$ 91	$ 134