Condensed Consolidated Balance Sheets - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Cash and cash equivalents	$ 51,621,000	$ 51,829,000
Insurance recovery of legal settlement	15,000,000	15,000,000
Prepaid expenses and other current assets	1,686,000	2,134,000
Total current assets	68,307,000	68,963,000
Property and equipment, net	1,011,000	1,113,000
Operating lease right-of-use assets	1,553,000	3,051,000
Other noncurrent assets	480,000	111,000
Total assets	71,351,000	73,238,000
Accounts payable	1,448,000	991,000
Accrued legal settlement	15,000,000	15,000,000
Accrued expenses	2,186,000	1,589,000
Current loan payable	2,000,000	0
Current operating lease liabilities	1,050,000	1,442,000
Accrued compensation	638,000	912,000
Interest payable	101,000	92,000
Total current liabilities	22,423,000	20,026,000
Loan payable (net of discount and issuance costs of $524 and $756, respectively)	13,301,000	15,069,000
Operating lease liabilities, less current portion	695,000	2,026,000
Total liabilities	36,419,000	37,121,000
Commitments and contingencies (Note 6)
Common stock, $0.001 par value; 100,000,000 shares authorized at March 31, 2022 and December 31, 2021; 7,173,094 and 6,910,324 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	10,000	7,000
Additional paid-in capital	152,644,000	136,173,000
Accumulated deficit	(117,722,000)	(100,063,000)
Total stockholders’ equity	34,932,000	36,117,000
Total liabilities and stockholders’ equity	$ 71,351,000	$ 73,238,000