Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Stock issued for services	$ 1,504	$ 1,428
Accrued compensation	27	42
Stock issued for acquisition of program	1,462	1,436
Stock issued for license agreement	1,363	1,574
Stock issued for milestone payment	236	262
Amortizable license fee	4	5
Net operating loss carry-forward	16,884	12,540
Total gross deferred tax assets	21,480	17,287
Less: valuation allowance	(21,480)	(17,287)
Total net deferred tax assets	$ 0	$ 0