CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets
Cash and cash equivalents	$ 15,697	$ 39,462
Prepaid expenses and other current assets	2,920	3,509
Total current assets	18,617	42,971
Property and equipment, net	17,474	17,290
Restricted cash	302	0
Other assets	4,149	4,286
Total assets	40,542	64,547
Current liabilities
Accounts payable	3,391	3,172
Accrued expenses and other current liabilities	12,814	13,343
Operating lease obligations	461	574
Current portion of long term debt	1,306	0
Total current liabilities	17,972	17,089
Non-current liabilities
Operating lease obligations, less current portion	3,546	3,567
Long term debt, net	1,552	2,800
Other non-current liabilities	545	527
Total non-current liabilities	5,643	6,894
Total liabilities	23,615	23,983
Commitments and contingencies
Stockholders' equity
Convertible preferred stock; $0.01 par value; 10,000,000 shares authorized at June 30, 2024 and December 31, 2023	0	1
Common stock; $0.01 par value; 295,000,000 shares authorized, 257,542,624 and 256,688,304 shares issued, and 257,421,124 and 256,566,804 shares outstanding at June 30, 2024 and December 31, 2023, respectively	2,576	2,567
Treasury stock, at cost, 121,500 shares at June 30, 2024 and December 31, 2023	(48)	(48)
Additional paid-in capital	327,742	324,191
Accumulated other comprehensive income	28	20
Accumulated deficit	(313,371)	(286,167)
Total stockholders' equity	16,927	40,564
Total liabilities and stockholders' equity	$ 40,542	$ 64,547