Leases (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) ft²	Sep. 30, 2021 USD ($) ft²	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) ft² item	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease liabilities, current portion included in other accrued liabilities	$ 6,922	$ 6,922		$ 6,922		$ 7,300
Operating lease liabilities, long-term portion	48,388	48,388		48,388		$ 21,246
Operating lease liabilities	$ 55,310	$ 55,310		55,310
Noncash investing activities related to right-of-use assets				$ 31,300
Weighted average remaining lease term	3 years 7 months 28 days	3 years 7 months 28 days		3 years 7 months 28 days
Weighted average discount rate (as a percent)	7.48%	7.48%		7.48%
Lease expense		$ 2,800	$ 1,900	$ 8,100	$ 5,800
Operating lease payments		$ 2,600	$ 2,200	$ 7,600	$ 6,600
Minimum
Lessee, Lease, Description [Line Items]
Term of lease	3 years	3 years		3 years
Maximum
Lessee, Lease, Description [Line Items]
Term of lease	5 years	5 years		5 years
Corporate Headquarters Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²	113,000	113,000		113,000
Number of office space locations | item				2
Term of lease	84 months	84 months		84 months
Renewal term of lease	5 years	5 years		5 years
"First Space" Sublease
Lessee, Lease, Description [Line Items]
Number of office space locations | ft²				88,000
"Second Space" Sublease
Lessee, Lease, Description [Line Items]
Number of office space locations | ft²				25,000
Corporate Headquarters Lease Amendment
Lessee, Lease, Description [Line Items]
Annual lease payment				$ 9,300
Term of lease	48 months	48 months		48 months
Austin TX, Long-term Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²	94,000	94,000		94,000
Term of lease	132 months	132 months		132 months
Tukwila, WA Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²	10,000	10,000		10,000
Term of lease	62 months	62 months		62 months
Renewal term of lease	5 years	5 years		5 years
San Carlos, CA Sublease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²	25,879	25,879		25,879
Term of lease	48 months	48 months		48 months
Sublease receivable	$ 1,900	$ 1,900		$ 1,900
San Carlos, CA Sublease Amendment
Lessee, Lease, Description [Line Items]
Noncash investing activities related to right-of-use assets				$ 29,700
San Carlos, CA Sublease Amendment | Rentable square feet surrendered in lease amendment
Lessee, Lease, Description [Line Items]
Office space (area) | ft²	25,879	25,879		25,879
South San Francisco, CA Lease
Lessee, Lease, Description [Line Items]
Office space (area) | ft²	11,395	11,395		11,395
Annual lease payment				$ 900
Term of lease	36 months	36 months		36 months
Vancouver, British Columbia, Canada
Lessee, Lease, Description [Line Items]
Office space (area) | ft²	7,107	7,107		7,107
Annual lease payment	$ 200
Term of lease	24 months	24 months		24 months