Leases (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($) ft²	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($) ft²
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to renew				true
Operating Lease Cost (Cost resulting from lease payments)	$ 1,733		$ 1,044	$ 3,502	$ 2,094
Operating Lease - Operating Cash Flows (Fixed Payments)	1,379		1,012	2,570	2,025
Operating Lease - ROU assets	37,137		7,425	37,137	7,425
Operating Lease - Liabilities	$ 37,137		$ 7,425	$ 37,137	$ 7,425
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 6 months		3 years 4 months 24 days	8 years 6 months	3 years 4 months 24 days
Weighted Average Discount Rate - Operating Leases	4.53%		5.26%	4.53%	5.26%
Area of office space | ft²			54,910		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