CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 41,785	$ 76,938
Prepaid manufacturing services	9,063	7,315
Prepaid expenses and other current assets	5,161	5,918
Total current assets	56,009	90,171
Property and equipment, net of accumulated depreciation of $13,938 and $11,809	21,557	23,479
Restricted cash	4,170	4,170
Operating right-of-use assets	21,304	21,957
Prepaid manufacturing services, net of current portion	29,670	31,893
Total assets	132,710	171,670
Current liabilities:
Accounts payable	1,131	1,838
Accrued expenses	7,699	9,703
Deferred revenue	292	12,963
Operating lease liabilities	2,891	2,661
Total current liabilities	12,013	27,165
Long-term liabilities:
Deferred revenue, net of current portion	17,341	30,686
Note payable, net of discount	25,596	25,430
Operating lease liabilities, net of current portion	33,362	34,884
Total liabilities	88,312	118,165
Commitments and contingencies (Note 7)
Stockholders' equity:
Common stock, $0.0001 par value; 150,000,000 shares authorized as of June 30, 2022 and December 31, 2021; 22,493,867 and 22,383,830 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively	2	2
Additional paid-in capital	384,446	378,750
Accumulated deficit	(340,050)	(325,247)
Total stockholders' equity	44,398	53,505
Total liabilities and stockholders' equity	$ 132,710	$ 171,670