CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net loss	$ (71,129)	$ (68,128)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,103	1,429
Impairment of inventories	102	842
Change in fair value of warrant liability	(28)	(787)
Stock-based compensation	13,004	12,218
Amortization of right-of-use assets	1,498	1,422
Realized loss on available-for-sale securities	0	29
Amortization of premium and accretion of discount on available-for-sale securities, net	(1,420)	636
Changes in operating assets and liabilities:
Accounts receivable	2,019	1,988
Inventories	61	(296)
Other current assets	(352)	(3,230)
Other noncurrent assets	(5)	(1)
Accounts payable	85	(359)
Accrued liabilities	(6,738)	(1,788)
Accrued employee costs	(1,205)	(30)
Lease liability	(1,459)	(1,404)
Other current liabilities	45	512
Net cash used in operating activities	(63,419)	(57,971)
Cash flows from investing activities:
Purchase of property, plant and equipment	(2,388)	(3,872)
Purchase of available-for-sale securities	(74,126)	(139,714)
Proceeds from maturities of available-for-sale securities	107,094	217,968
Net cash provided by investing activities	30,580	74,382
Cash flows from financing activities:
Payments of taxes withheld on net settled vesting of restricted stock units	(20)	(418)
Proceeds from exercise of warrants	0	0
Proceeds from exercise of stock options	116	244
Net cash (used in) provided by financing activities	96	(173)
Net (decrease) increase in cash and cash equivalents	(32,743)	16,238
Beginning cash and cash equivalents	67,420	66,810
Ending cash and cash equivalents	34,677	83,048
Supplemental disclosures of cash flow information:
Cash paid for interest	0	0
Cash paid for income taxes	0	0
Supplemental disclosures of non-cash investing and financing activities:
Unpaid property, plant and equipment purchases	$ 812	$ 491