CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 76,938	$ 88,915
Prepaid manufacturing services	7,315	101
Prepaid expenses and other current assets	5,918	4,742
Total current assets	90,171	93,758
Property and equipment, net	23,479	31,410
Restricted cash	4,170	4,170
Operating right-of-use assets	21,957	22,003
Prepaid manufacturing services, net of current portion	31,893
Total assets	171,670	151,341
Current liabilities:
Accounts payable	1,838	2,018
Accrued expenses	9,703	8,870
Deferred revenue	12,963	5,281
Operating lease liabilities	2,661	1,482
Total current liabilities	27,165	17,651
Long-term liabilities:
Deferred revenue, net of current portion	30,686	57,416
Note payable, net of discount	25,430	24,960
Operating lease liabilities, net of current portion	34,884	36,540
Other long-term liabilities		207
Total liabilities	118,165	136,774
Commitments and contingencies (Note 8)
Stockholders' equity:
Common stock, $0.0001 par value; 150,000,000 shares authorized as of December 31, 2021 and December 31, 2020; 22,383,830 and 18,787,579 shares issued and outstanding as of December 31, 2021 and December 31, 2020, respectively	2	2
Additional paid-in capital	378,750	302,655
Accumulated deficit	(325,247)	(288,090)
Total stockholders' equity	53,505	14,567
Total liabilities and stockholders' equity	$ 171,670	$ 151,341