Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 45,076	$ 140,517
Investments	261,964	215,877
Prepaid expenses and other current assets	5,034	7,666
Total current assets	312,074	364,060
Property and equipment, net	32,986	29,009
Goodwill	39,154	39,154
Intangible assets	25,724	25,724
Restricted cash	1,362	1,340
Deposits	542	608
Investments	0	43,276
Operating lease right-of-use assets	4,345	1,972
Finance lease right-of-use asset	45,594	46,664
Total assets	461,781	551,807
Current liabilities:
Accounts payable and accrued expenses	31,353	36,660
Operating lease liabilities, current	1,233	773
Finance lease liability, current	1,760	1,736
Total current liabilities	34,346	39,169
Operating lease liabilities, non-current	3,074	1,088
Finance lease liability, non-current	19,319	19,269
Other liabilities	2,072	2,595
Total liabilities	58,811	62,121
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock, $0.01 par value, 120,000,000 shares authorized; 80,521,415 and 79,123,312 shares issued and 80,518,844 and 79,120,741 shares outstanding at June 30, 2023 and December 31, 2022, respectively	805	791
Treasury stock, at cost, 2,571 common shares at June 30, 2023 and December 31, 2022	(47)	(47)
Additional paid-in capital	1,240,745	1,203,074
Accumulated other comprehensive loss	(722)	(357)
Accumulated deficit	(837,811)	(713,775)
Total stockholders' equity	402,970	489,686
Total liabilities and stockholders' equity	461,781	551,807
Series A Convertible Preferred Shares [Member]
Stockholders' equity:
Preferred stock	0	0
Series B Convertible Preferred Shares [Member]
Stockholders' equity:
Preferred stock	$ 0	$ 0