Leases - Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Short-term lease cost	$ 142	$ 690
Cash paid for amounts included in measurement of lease liabilities		$ 1,200
Weighted average remaining lease term	7 years 3 months 18 days	7 years 3 months 18 days
Weighted-average discount rate (percent)	6.00%	6.00%
Emeryville lease
Lessee, Lease, Description [Line Items]
Length of each lease renewal	5 years	5 years
Short-term Lease Terminated in March 2019
Lessee, Lease, Description [Line Items]
Short-term lease cost	$ 200	$ 200