Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash, cash equivalents and restricted cash	$ 33,238,000	$ 46,013,000
Short-term investments	19,799,000	49,704,000
Accounts receivable	424,000	20,000
Prepaid expenses and other current assets	3,639,000	3,714,000
Total current assets	57,100,000	99,451,000
Property and equipment, net	12,926,000	15,585,000
Right-of-use assets, net	25,753,000	25,715,000
Intangible assets, net	4,472,000	5,020,000
Goodwill	4,508,000	4,508,000
Other long-term assets	883,000	3,568,000
Total assets	105,642,000	153,847,000
Current liabilities:
Accounts payable	1,339,000	5,514,000
Deferred grant revenue	79,000	2,000,000
Other accrued current liabilities	5,991,000	8,084,000
Current portion of operating lease liability	2,517,000	2,228,000
Current portion of liability related to sale of future royalties	1,342,000	95,000
Total current liabilities	11,268,000	17,921,000
Operating lease liability, net of current portion	17,942,000	19,477,000
Liability related to sale of future royalties, net of current portion	4,633,000	5,621,000
Other long-term liabilities	278,000	231,000
Total liabilities	34,121,000	43,250,000
Commitments and contingencies (Note 8)
Stockholders’ equity:
Preferred stock: $0.0001 par value; 5,000,000 shares authorized; none issued and outstanding as of September 30, 2023 and December 31, 2022	0	0
Common stock: $0.0001 par value; 250,000,000 shares authorized as of September 30, 2023 and December 31, 2022; 152,081,196 shares issued and 152,037,358 shares outstanding as of September 30, 2023 and 134,199,429 shares issued and outstanding as of December 31, 2022	15,000	13,000
Additional paid-in capital	463,755,000	437,992,000
Treasury stock at cost, 43,838 shares as of September 30, 2023 and none as of December 31, 2022, respectively	(39,000)	0
Accumulated deficit	(392,199,000)	(327,109,000)
Accumulated other comprehensive loss	(11,000)	(299,000)
Total stockholders’ equity	71,521,000	110,597,000
Total liabilities and stockholders’ equity	$ 105,642,000	$ 153,847,000