Leases (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) Location	Dec. 31, 2019 USD ($)	Jan. 01, 2019
Lessee Lease Description [Line Items]
Number of locations | Location	3
Lessee operating lease, incremental borrowing rate			5.25%
Lease expense | $	$ 0.6	$ 0.5
Burlingame, CA [Member]
Lessee Lease Description [Line Items]
Lease termination date	Apr. 30, 2021
Hayward, CA [Member]
Lessee Lease Description [Line Items]
Warehouse lease, effective date	May 01, 2021