CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating activities
Net loss	$ (26,773)	$ (28,071)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	(3)	463
Non-cash lease expense	902	842
Stock-based compensation	2,912	3,722
Change in derivative liabilities	70	15
Debt refinancing costs	0	102
Gain on sale of equipment	0	(710)
Impairment of long-lived assets	429	0
Non-cash interest expense	1,044	109
Changes in operating assets and liabilities:
Accounts receivable	(4,387)	(3,892)
Inventory	(16,601)	(3,487)
Prepaid commercial manufacturing	(268)	(9,393)
Prepaid expenses and other assets	(774)	9,086
Accounts payable	(346)	753
Accrued compensation and benefits	(2,474)	882
Operating lease liabilities	(937)	(836)
Accrued and other liabilities	(1,396)	(1,041)
Deferred revenue	3,807	3,836
Net cash used in operating activities	(44,795)	(27,620)
Investing activities
Proceeds from maturities and redemptions of investments	11,000	27,300
Purchases of investments	(20,763)	(25,763)
Proceeds from sale of property and equipment	0	795
Purchases of property and equipment	(14)	0
Net cash (used in) provided by investing activities	(9,777)	2,332
Financing activities
Proceeds from 2022 Loan, net of issuance costs	0	26,971
Payments for 2018 Loan, net of costs	0	(33,038)
Proceeds from issuance of common stock in at the market offering, net of issuance costs	50,719	5,921
Proceeds from issuance of common stock under equity incentive and stock purchase plans	200	83
Net cash provided by (used in) financing activities	50,919	(63)
Net decrease in cash and cash equivalents	(3,653)	(25,351)
Cash and cash equivalents at beginning of period	96,140	72,428
Cash and cash equivalents at end of period	92,487	47,077
Supplementary disclosure of cash flow information:
Cash paid for interest	860	741
Cash paid for income taxes	0	1
Supplementary disclosure of non-cash activities:
Issuance of derivative in connection with issuance of loan payable	$ 0	$ 375