Leases - Schedule of Right-of-Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Lessee Lease Description [Line Items]
Right-of-use assets	$ 830	$ 963
Lease liabilities	865	1,003
Del Mar, CA [Member]
Lessee Lease Description [Line Items]
Right-of-use assets	579	613
Lease liabilities	608	641
Burlingame, CA [Member]
Lessee Lease Description [Line Items]
Right-of-use assets	23	99
Lease liabilities	28	109
Edwardsville, IL [Member]
Lessee Lease Description [Line Items]
Right-of-use assets	228	251
Lease liabilities	$ 229	$ 253