Leases - Narrative (Details) $ in Millions	Sep. 30, 2019 USD ($) ft²
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term	6 years 8 months 12 days
Weighted average discount rate	12.30%
Brisbane, California Office Space
Lessee, Lease, Description [Line Items]
Area leased (in sq ft) | ft²	40,232
Extension term	7 years
Letters of credit	$ 0.5
Reduced letter of credit if conditions met	$ 0.2