Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 196,669	$ 232,694
Investments	109,865	156,046
Prepaid expenses and other current assets	4,597	3,319
Total current assets	311,131	392,059
Property and equipment, net	25,613	22,299
Goodwill	30,815	30,815
Restricted cash	1,354	1,343
Deposits	455	455
Operating lease right-of-use assets	1,022	1,569
Finance lease right-of-use asset	46,875	48,480
Total assets	417,265	497,020
Current liabilities:
Accounts payable and accrued expenses	27,823	19,615
Operating lease liabilities, current	634	863
Finance lease liability, current	1,724	1,689
Total current liabilities	30,181	22,167
Operating lease liabilities, non-current	492	905
Finance lease liability, non-current	19,242	19,144
Other liabilities	37	80
Total liabilities	49,952	42,296
Commitments and contingencies (Note 10)
Stockholders' equity:
Common stock, $0.01 par value, 120,000,000 shares authorized; 67,838,803 and 64,505,889 shares issued and outstanding at September 30, 2022 and December 31, 2021, respectively	678	645
Additional paid-in capital	1,014,283	946,152
Accumulated other comprehensive loss	(596)	(161)
Accumulated deficit	(647,052)	(491,912)
Total stockholders' equity	367,313	454,724
Total liabilities and stockholders' equity	417,265	497,020
Series A Convertible Preferred Shares [Member]
Stockholders' equity:
Preferred stock	0	0
Series B Convertible Preferred Shares [Member]
Stockholders' equity:
Preferred stock	$ 0	$ 0