CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (54,819)	$ (71,004)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	667	831
Amortization of debt discount and issuance costs	1,182	2,114
Amortization of right-of-use asset	812	889
Change in fair value of warrant liability	(559)	(3,382)
Loss on disposal of property, machinery, equipment and intangible assets	17	121
Stock-based compensation expense	6,453	8,564
Non-cash consulting expense	112	0
Changes in operating assets and liabilities:
Accounts receivable	(44)	0
Prepaids and other current assets	(297)	(1,571)
Other non-current assets	2,644	(901)
Accounts payable	278	(328)
Accrued liabilities	(610)	(1,873)
Accrued interest	118	92
Other current liabilities	(2)	(4,967)
Contract liabilities	(1,098)	851
Lease liability	(859)	(908)
Other non-current liabilities	18	(23)
Net cash used in operating activities	(45,987)	(71,495)
Cash flows from investing activities:
Purchases of property, machinery and equipment	(94)	(618)
Proceeds from sale of property, machinery and equipment	113	7
Purchases of intangible assets	(26)	(30)
Net cash used in investing activities	(7)	(641)
Cash flows from financing activities:
Proceeds from exercise of stock options	130	517
Proceeds from employee stock purchase plan	31	190
Repurchase of Section 16 Officer shares for tax coverage exchange	(87)	(265)
Principal payments on loan payable	(9,592)	(6,686)
Payment of deferred offering costs	(252)	0
Payment for repurchase of common shares	(10,000)	0
Proceeds from issuance of common stock and related warrants	15,000	0
Payments for issuance costs related to common stock and related warrants	(1,135)	0
Net cash used in financing activities	(5,905)	(6,244)
Decrease in cash, cash equivalents and restricted cash	(51,899)	(78,380)
Cash, cash equivalents and restricted cash, beginning of period	62,413	160,547
Cash, cash equivalents and restricted cash, end of period	10,514	82,167
Supplemental disclosure of non-cash investing and financing activities
Purchases of intangible assets in accounts payable and accrued liabilities at period end	5	0
Issuance costs related to warrant modification	648	0
Deferred offering costs in accounts payable and accrued liabilities at period end	0	238
Stock repurchase liability fair value	0	10,000
Supplemental disclosure of cash flow information
Cash paid for interest	$ 882	$ 1,960