CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets
Cash and cash equivalents	$ 68,259	$ 77,563
Marketable securities	8,462	13,371
Prepaid expenses and other current assets	7,680	7,558
Total current assets	84,401	98,492
Property and equipment, net	7,952	6,053
Other assets	3,946	4,087
Total assets	96,299	108,632
Current liabilities
Accounts payable	8,092	8,062
Accrued expenses and other current liabilities	5,823	9,900
Operating lease obligations	512	498
Current portion of long term debt	1,256	0
Total current liabilities	15,683	18,460
Non-current liabilities
Operating lease obligations, less current portion	3,449	3,587
Long term debt, net	1,058	2,289
Other non-current liabilities	309	244
Total non-current liabilities	4,816	6,120
Total liabilities	20,499	24,580
Commitments and contingencies (Note 13)
Stockholders' equity
Common stock; $0.01 par value; 295,000,000 shares authorized, 226,548,693 and 221,721,182 shares issued, and 226,427,193 and 221,599,682 shares outstanding at March 31, 2023 and December 31, 2022, respectively	2,265	2,217
Treasury stock, at cost, 121,500 shares at March 31, 2023 and December 31, 2022	(48)	(48)
Additional paid-in capital	303,073	294,874
Accumulated other comprehensive income	25	26
Accumulated deficit	(229,516)	(213,018)
Total stockholders' equity	75,800	84,052
Total liabilities and stockholders' equity	96,299	108,632
Series A Preferred Stock
Stockholders' equity
Preferred stock issued	0	0
Series B Preferred Stock
Stockholders' equity
Preferred stock issued	$ 1	$ 1