Leases (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) ft² location	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Feb. 28, 2021 ft²
Lessee, Lease, Description [Line Items]
Operating lease liabilities, current portion included in other accrued liabilities		$ 7,300	$ 5,739
Operating lease liabilities, long-term portion		21,246	$ 26,297
Operating lease liabilities		$ 28,546
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]		us-gaap:OtherCurrentLiabilitiesMember	us-gaap:OtherCurrentLiabilitiesMember
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]		us-gaap:OtherNoncurrentLiabilitiesMember	us-gaap:OtherNoncurrentLiabilitiesMember
Noncash investing activities related to right-of-use assets		$ 2,400
Weighted average remaining lease term		2 years 3 months 10 days
Weighted average discount rate (as a percent)		10.68%
Lease expense		$ 7,800	$ 7,800	$ 7,400
Impairment of right-of-use assets			400
Operating lease payments		$ 9,000	$ 8,600	$ 7,900
Corporate Headquarters Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²		113,000
Number of office space locations | location		2
Term of lease		84 months
Renewal term of lease		5 years
"First Space" Sublease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²		88,000
"Second Space" Sublease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²		25,000
Corporate Headquarters Lease Amendment | Subsequent Event
Lessee, Lease, Description [Line Items]
Renewal term of lease	48 months
Lease expense	$ 9,300
Austin TX, Long-term Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²		94,000
Term of lease		132 months
Tukwila, WA Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²		10,000
Term of lease		62 months
Renewal term of lease		5 years
San Carlos, CA Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²		25,879
Term of lease		48 months
Lease expense		$ 1,900
San Carlos, CA Lease | Subsequent Event
Lessee, Lease, Description [Line Items]
Office space (area) | ft²					22,405
San Carlos, CA Lease | Subsequent Event | Rentable square feet returned in lease amendment
Lessee, Lease, Description [Line Items]
Office space (area) | ft²					3,474
South San Francisco, CA Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²		11,395
Term of lease		36 months
Lease expense		$ 900