Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Valuation allowance on deferred tax assets	$ 107,061	$ 55,357	$ 48,500
Increase in valuation allowance recorded as an expense	34,300	35,100
Decrease in valuation allowance charged to equity	17,400	(28,200)
Net operating loss carryforwards, not subject to expiration	475,200
Unrecognized tax benefits	2,917	$ 3,615	$ 2,053	$ 1,921
Refund claims related to prior years	600
Expiration between 2023 and 2026
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	5,100
Expiration between 2030 and 2037
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	73,100
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	553,400
Federal | Expiration between 2030 and 2037
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards generated in taxable years ending on or before December 31 2017	78,200
Federal | Proficient
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	5,100
Federal | Tenfold
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	51,800
Federal | VoiceBase
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	65,600
Foreign
Operating Loss Carryforwards [Line Items]
Increase in valuation recorded	51,700
Foreign | Australian Taxation Office
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	1,900
Foreign | Federal Ministry of Finance, Germany
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	10,900
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	387,000
Net operating loss carryforwards, not subject to expiration	86,300
State | Expiration between 2022 and 2041
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, subject to expiration	$ 300,700