Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 73,002	$ 88,756
Grants receivable	0	806
Prepaid expenses and other current assets	3,237	1,685
Total current assets	76,239	91,247
Property and equipment, net	419	451
Operating lease right-of-use assets	3,790	3,986
Investments in related parties	732	723
Other assets	78	106
Total assets	81,258	96,513
Current liabilities
Accounts payable	3,433	4,710
Accrued expenses	5,242	3,219
Operating lease liabilities, current	918	894
Financing obligation, current	60	58
Deferred revenue, current	653	2,301
Warrant liability	75	114
Total current liabilities	10,381	11,296
Operating lease liabilities, noncurrent	3,236	3,475
Financing obligation, noncurrent	219	235
Other liabilities, noncurrent	220	0
Total liabilities	14,056	15,006
Commitments and contingencies (Note 9)
Stockholders' equity
Common stock, $0.01 par value per share; 300,000,000 and 300,000,000 shares authorized, 29,959,425 and 29,959,060 shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively	300	300
Additional paid-in capital	296,476	296,445
Accumulated other comprehensive loss	(199)	(103)
Accumulated deficit	(229,375)	(215,135)
Total stockholders' equity	67,202	81,507
Total liabilities and stockholders' equity	$ 81,258	$ 96,513