Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 109,860	$ 298,887
Short-term investment securities	66,082	15,876
Accounts receivable, net		1,389
Prepaid research and development	4,026	11,929
Other current assets	2,954	2,884
Total current assets	182,922	330,965
Restricted cash	1,269	1,264
Long-term investment securities	21,766	35,533
Right of use assets	9,079	8,629
Leasehold interest, net	1,680	1,839
Equipment, net	376	600
Goodwill	799	799
Total assets	217,891	379,629
Current liabilities:
Accounts payable and accrued expenses	29,726	51,294
Other current liabilities	807	1,512
Loan payable - current portion		975
Lease liability - current portion	1,616	1,437
Accrued compensation	4,298	10,166
Total current liabilities	36,447	65,384
Deferred revenue, net of current portion	343	457
Loan payable - non-current	70,038	66,788
Lease liability - non-current	10,582	9,847
Total liabilities	117,410	142,476
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value per share (175,000,000 shares authorized, 145,399,144 and 143,292,043 shares issued, 145,357,835 and 143,250,734 shares outstanding at September 30, 2022 and December 31, 2021, respectively)	145	143
Additional paid-in capital	1,574,609	1,565,942
Treasury stock, at cost, 41,309 shares at September 30, 2022 and December 31, 2021	(234)	(234)
Accumulated deficit	(1,474,039)	(1,328,698)
Total stockholders' equity	100,481	237,153
Total liabilities and stockholders' equity	$ 217,891	$ 379,629