Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Stock issued for services	$ 1,428	$ 1,223
Accrued compensation	42	20
Stock issued for acquisition of program	1,436	1,301
Stock issued for license agreement	1,574	1,574
Stock issued for milestone payment	262	255
Amortizable license fee	5	5
Net operating loss carry-forward	12,540	8,494
Total gross deferred tax assets	17,287	12,872
Less: valuation allowance	(17,287)	(12,872)
Total net deferred tax assets	$ 0	$ 0