Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets
Cash	$ 61,772	$ 78,734
Prepaid expenses and other current assets	8,895	4,727
Total current assets	70,667	83,461
Operating lease right-of-use asset	26	39
Total assets	70,693	83,500
Current liabilities
Accounts payable	2,127	1,693
Accrued expenses	3,549	3,728
Licenses payable		200
Short-term portion of convertible notes payable, at fair value	4,238	1,030
Derivative liability		1,174
Warrant liabilities, at fair value	190	424
Operating lease liability	26	38
Total current liabilities	10,130	8,287
Convertible notes payable, at fair value	14,926	17,890
Total liabilities	25,056	26,177
Commitments and contingencies (note 12)
Stockholders’ equity
Common stock, $0.001 par value, 240,000,000 shares authorized,          105,590,773 and 105,500,445 issued and outstanding as of          March 31, 2022 and December 31, 2021, respectively	105	105
Additional paid-in-capital	200,743	198,428
Accumulated deficit	(155,211)	(141,210)
Total stockholders’ equity	45,637	57,323
Total liabilities and stockholders’ equity	$ 70,693	$ 83,500