Consolidated Balance Sheets - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 32,938,000	$ 12,596,000
Short-term investments	12,086,000	82,438,000
Accounts receivable	3,000,000
Prepaid expenses, other current assets and restricted cash	7,377,000	2,708,000
Total current assets	55,401,000	97,742,000
Property and equipment, net	12,339,000	11,322,000
Right-of-use lease assets	9,403,000	7,032,000
Licensed technology, net	1,384,000	1,500,000
Goodwill		32,466,000
Other assets and restricted cash	1,059,000	1,136,000
Total assets	79,586,000	151,198,000
Current liabilities:
Accounts payable	4,325,000	4,695,000
Accrued expenses	5,585,000	3,410,000
Current portion of lease liability	1,818,000	1,713,000
Current portion of PPP loan payable		330,000
Current portion of payable to licensor	4,599,000	31,515,000
Deferred revenue	296,000	296,000
Total current liabilities	16,623,000	41,959,000
PPP loan payable		1,428,000
Payable to licensor	3,828,000
Other long-term liabilities	200,000
Long-term lease liabilities	7,560,000	5,260,000
Total liabilities	28,211,000	48,647,000
Commitments and contingencies
Stockholders’ equity:
Preferred stock - $0.01 par value; authorized 2,000,000 shares; no issued and outstanding shares at December 31, 2021 and 2020
Common stock - $0.01 par value; authorized 200,000,000 shares; issued and outstanding 147,205,422 at December 31, 2021; issued and outstanding 96,131,678 at December 31, 2020	1,472,000	961,000
Additional paid-in capital	705,570,000	672,304,000
Accumulated deficit	(655,640,000)	(570,704,000)
Accumulated other comprehensive loss	(27,000)	(10,000)
Total stockholders’ equity	51,375,000	102,551,000
Total liabilities and stockholders’ equity	$ 79,586,000	$ 151,198,000