Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 121,414	$ 61,761
Trade receivables, net	1,144	1,197
Partnership receivables	1,422
Clinical trial retainers	587	355
Other prepaid expenses and other current assets	1,495	2,195
Total current assets	126,062	65,508
Property and equipment, net	326	343
Operating lease right-of-use asset	790	903
Other assets	258	158
Total assets	127,436	66,912
Current liabilities:
Accounts payable	3,963	3,380
Accrued clinical trial costs and contract research	5,285	4,550
Other accrued liabilities	4,723	4,463
Operating lease liability	331	369
Loans payable, net of discount		1,056
Deferred revenue	1,974	1,974
Deferred research and development reimbursements	112	164
PIPE Warrant liability (Note 7)	2,595	199
Other liabilities (Note 6)	790	790
Total current liabilities	19,773	16,945
Loans payable, net of current portion and discount	32,437	12,716
Deferred revenue, non-current	85	578
Operating lease liability, non-current	261	336
Other liabilities, non-current (Note 6)	2,432	1,043
Total liabilities	54,988	31,618
Stockholders’ equity:
Preferred stock, $.001 par value: 5,000 shares authorized at March 31, 2021 and December 31, 2020; no shares issued and outstanding at each of March 31, 2021 and December 31, 2020
Common stock, $.001 par value: 50,000 shares authorized at March 31, 2021 and December 31, 2020; 34,361 shares issued and outstanding at March 31, 2021 and 26,883 issued and outstanding at December 31, 2020	34	27
Additional paid-in capital	715,741	656,472
Accumulated deficit	(643,327)	(621,205)
Total stockholders’ equity	72,448	35,294
Total liabilities and stockholders’ equity	$ 127,436	$ 66,912