CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 53,477	$ 77,563
Marketable securities	0	13,371
Prepaid expenses and other current assets	3,081	7,558
Total current assets	56,558	98,492
Property and equipment, net	14,469	6,053
Other assets	3,660	4,087
Total assets	74,687	108,632
Current liabilities
Accounts payable	2,921	8,062
Accrued expenses and other current liabilities	6,399	9,900
Operating lease obligations	540	498
Current portion of long term debt	1,276	0
Total current liabilities	11,136	18,460
Non-current liabilities
Operating lease obligations, less current portion	3,164	3,587
Long term debt, net	1,495	2,289
Other non-current liabilities	497	244
Total non-current liabilities	5,156	6,120
Total liabilities	16,292	24,580
Commitments and contingencies
Stockholders' equity
Common stock; $0.01 par value; 295,000,000 shares authorized, 256,621,487 and 221,721,182 shares issued, and 256,499,987 and 221,599,682 shares outstanding at September 30, 2023 and December 31, 2022, respectively	2,566	2,217
Treasury stock, at cost, 121,500 shares at September 30, 2023 and December 31, 2022	(48)	(48)
Additional paid-in capital	322,452	294,874
Accumulated other comprehensive income	27	26
Accumulated deficit	(266,603)	(213,018)
Total stockholders' equity	58,395	84,052
Total liabilities and stockholders' equity	74,687	108,632
Series A Preferred Stock
Stockholders' equity
Preferred stock issued	0	0
Series B Preferred Stock
Stockholders' equity
Preferred stock issued	$ 1	$ 1