Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Valuation allowance on deferred tax assets	$ 55,357	$ 48,451	$ 30,200
Increase in valuation allowance recorded as an expense	35,100	25,000
Decrease in valuation allowance charged to equity	28,200	6,700
Unrecognized tax benefits	3,615	$ 2,053	$ 1,921
Refund claims related to prior years	600
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	311,700
Operating loss carryforwards generated in taxable years ending on or before December 31 2017	41,200
Net operating loss carryforwards, not subject to expiration	270,400
Federal | Expiration between 2023 and 2026
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	6,000
Federal | Expiration between 2036 and 2037
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	35,200
Federal | Proficient
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	5,100
Foreign
Operating Loss Carryforwards [Line Items]
Increase in valuation recorded	6,900
Foreign | Australian Taxation Office
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	2,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	221,900
Net operating loss carryforwards, not subject to expiration	47,300
State | Expiration between 2023 and 2040
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	$ 174,600