Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 20,165	$ 34,767
Restricted cash, current	1,373	1,213
Accounts receivable, net	1,990	4,952
Short-term investments	87,899	105,047
Inventory	3,366	0
Prepaid expenses and other current assets	3,305	5,657
Total current assets	118,098	151,636
Property and equipment, net	16,266	17,570
Intangible assets, net	4,923	0
Operating lease right-of-use assets	2,167	3,401
Restricted cash, non-current	945	675
Other non-current assets	833	271
Total assets	143,232	173,553
Current liabilities:
Accounts payable	2,755	3,036
Accrued and other current liabilities	10,755	14,125
Accrued product warranties	2,129	1,643
Operating lease liabilities, current	1,581	1,421
Deferred revenue, current	2,546	6,168
Notes payable, current	0	1,600
Total current liabilities	19,766	27,993
Notes payable, non-current	0	315
Operating lease liabilities, non-current	957	2,535
Deferred revenue	18,200
Common stock warrant liabilities	917	3,209
Other non-current liabilities	0	85
Total liabilities	39,875	36,579
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock ($0.0001 par value, 200,000,000 shares authorized, none issued and outstanding as of December 31, 2023 and 2022)	0	0
Common stock ($0.0001 par value; 2,000,000,000 shares authorized, 174,211,911 and 153,821,339 shares issued and outstanding as of December 31, 2023 and 2022, respectively)	18	16
Additional paid-in capital	799,496	755,537
Accumulated deficit	(696,157)	(618,579)
Total stockholders’ equity	103,357	136,974
Total liabilities and stockholders’ equity	143,232	173,553
Nonrelated party
Current liabilities:
Deferred revenue	3,835	2,442
Related party
Current liabilities:
Deferred revenue	$ 14,400	$ 0