Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 112,027	$ 106,438
Marketable securities	0	28,164
Accounts receivable	5,385	6,596
Unbilled receivables	1,055	3,162
Prepaid expenses and other current assets	4,258	3,778
Total current assets	122,725	148,138
Property and equipment, net	2,593	2,794
Right-of-use asset, net	10,775	11,617
Long-term restricted cash	1,377	1,311
Investments	2,000	2,000
Other assets	36	26
Total assets	139,506	165,886
Current liabilities:
Accounts payable	267	316
Accrued expenses	12,902	14,084
Loan payable	10,235	8,476
Lease liability	1,729	1,608
Deferred revenue	4,234	593
Total current liabilities	29,367	25,077
Non-current liabilities:
Loan payable, net of current portion	13,787	17,786
Lease liability	9,163	10,055
Deferred revenue	4,863	0
Warrant liabilities	16,878	19,140
Total liabilities	74,058	72,058
Commitments and contingencies (Note 17)
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding as of June 30, 2023 and December 31, 2022	0	0
Common stock, $0.0001 par value; 350,000,000 shares authorized; 153,427,571 and 153,042,435 shares issued and outstanding as of June 30, 2023 and December 31, 2022, respectively	15	15
Additional paid-in capital	498,016	493,308
Accumulated deficit	(427,987)	(394,937)
Accumulated other comprehensive loss	(4,596)	(4,558)
Total stockholders' equity	65,448	93,828
Total liabilities and stockholders' equity	$ 139,506	$ 165,886