Leases (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 ft²
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to renew				true
Operating Lease Cost (Cost resulting from lease payments)	$ 1,664		$ 1,035	$ 5,166	$ 3,129
Operating Lease - Operating Cash Flows (Fixed Payments)	1,463		1,040	4,032	3,066
Operating Lease - ROU assets	37,000		7,089	37,000	7,089
Operating Lease - Liabilities	$ 37,000		$ 7,089	$ 37,000	$ 7,089
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Operating Lease - Liabilities		Operating Lease - Liabilities	Operating Lease - Liabilities	Operating Lease - Liabilities
Weighted Average Lease Term - Operating Leases	8 years 5 months 12 days		3 years 7 months 2 days	8 years 5 months 12 days	3 years 7 months 2 days
Weighted Average Discount Rate - Operating Leases	4.54%		5.24%	4.54%	5.24%
Area of office space | ft²						54,910
Wallnut creek
Lessee, Lease, Description [Line Items]
Lease impairment and write-off of fixed assets and tenant improvements		$ 434
San Mateo
Lessee, Lease, Description [Line Items]
Lease impairment and write-off of fixed assets and tenant improvements		$ 625